Pub Date : 2020-11-11DOI: 10.1186/s12862-020-01719-z
Adrien Quiles, Rémi A Wattier, Karolina Bacela-Spychalska, Michal Grabowski, Thierry Rigaud
Background: Although the processes of co-evolution between parasites and their hosts are well known, evidence of co-speciation remains scarce. Microsporidian intracellular parasites, due to intimate relationships with their hosts and mixed mode of transmission (horizontal but also vertical, from mother to offspring), may represent an interesting biological model for investigating co-speciation. Amphipod crustaceans, especially gammarids, are regular hosts of microsporidian parasites, in particular the Dictyocoela spp., which have so far been found limited to these amphipods and are known to use a vertical mode of transmission. The amphipod genus Gammarus has a diversification history spanning the last 50-60 Mya and an extensive cryptic diversity in most of the nominal species. Here, we investigated the degree of co-diversification between Dictyocoela and Gammarus balcanicus, an amphipod with high degrees of ancient cryptic diversification and lineage endemism, by examining the genetic diversity of these parasites over the entire geographic range of the host. We hypothesised that the strong host diversification and vertical transmission of Dictyocoela would promote co-diversification.
Results: Using the parasite SSU rDNA as a molecular marker, analyzing 2225 host specimens from 88 sites covering whole host range, we found 31 haplogroups of Dictyocoela, 30 of which were novel, belonging to four Dictyocoela species already known to infect other Gammarus spp. The relationships between Dictyocoela and gammarids is therefore ancient, with the speciation in parasites preceding those of the hosts. Each novel haplogroup was nevertheless specific to G. balcanicus, leaving the possibility for subsequent co-diversification process during host diversification. A Procrustean Approach to Co-phylogeny (PACo) analysis revealed that diversification of Dictyocoela was not random with respect to that of the host. We found high degrees of congruence between the diversification of G. balcanicus and that of Dictyocoela roeselum and D. muelleri. However, we also found some incongruences between host and Dictyocoela phylogenies, e.g. in D. duebenum, probably due to host shifts between different G. balcanicus cryptic lineages.
Conclusion: The evolutionary history of Dictyocoela and Gammarus balcanicus represents an example of an overall host-parasite co-diversification, including cases of host shifts.
背景:尽管寄生虫与其宿主之间的共同进化过程已广为人知,但有关共同物种形成的证据仍然很少。微孢子虫细胞内寄生虫与其宿主关系密切,而且具有混合传播方式(水平传播,也有垂直传播,从母体传播给后代),因此可能是研究同种异化的一个有趣的生物模型。两足类甲壳动物,特别是伽马类,是微孢子虫寄生虫的固定宿主,特别是 Dictyocoela spp.。片脚类动物(Gammarus)属的多样化历史可追溯到五六千万年前,大多数标称物种都具有广泛的隐性多样性。在这里,我们通过研究这些寄生虫在宿主整个地理范围内的遗传多样性,研究了Dictyocoela和巴卡尼克斯(Gammarus balcanicus)之间的共同多样性程度,巴卡尼克斯是一种具有高度古老隐性多样性和世系特有性的片脚类动物。我们假设,Dictyocoela强烈的宿主多样化和垂直传播将促进共同多样化:使用寄生虫 SSU rDNA 作为分子标记,分析了来自 88 个地点的 2225 份宿主标本,覆盖了整个宿主分布区,我们发现了 31 个 Dictyocoela 单倍群,其中 30 个是新发现的,属于 4 个已知会感染其他伽马类的 Dictyocoela 物种。尽管如此,每一个新的单倍群都是巴卡尼克斯蜚蠊所特有的,因此在宿主多样化的过程中还存在着共同多样化的可能性。共系统进化方法(PACo)分析表明,Dictyocoela 的分化与宿主的分化并不是随机的。我们发现 G. balcanicus 的多样化与 Dictyocoela roeselum 和 D. muelleri 的多样化高度一致。然而,我们也发现了宿主与 Dictyocoela 系统发育之间的一些不一致之处,例如在 D. duebenum 中,这可能是由于宿主在不同的 G. balcanicus 隐蔽世系之间发生了转移:结论:Dictyocoela 和巴尔卡尼氏沼虾的进化史是宿主与寄生虫共同多样化的一个实例,其中包括宿主转移的情况。
{"title":"Dictyocoela microsporidia diversity and co-diversification with their host, a gammarid species complex (Crustacea, Amphipoda) with an old history of divergence and high endemic diversity.","authors":"Adrien Quiles, Rémi A Wattier, Karolina Bacela-Spychalska, Michal Grabowski, Thierry Rigaud","doi":"10.1186/s12862-020-01719-z","DOIUrl":"10.1186/s12862-020-01719-z","url":null,"abstract":"<p><strong>Background: </strong>Although the processes of co-evolution between parasites and their hosts are well known, evidence of co-speciation remains scarce. Microsporidian intracellular parasites, due to intimate relationships with their hosts and mixed mode of transmission (horizontal but also vertical, from mother to offspring), may represent an interesting biological model for investigating co-speciation. Amphipod crustaceans, especially gammarids, are regular hosts of microsporidian parasites, in particular the Dictyocoela spp., which have so far been found limited to these amphipods and are known to use a vertical mode of transmission. The amphipod genus Gammarus has a diversification history spanning the last 50-60 Mya and an extensive cryptic diversity in most of the nominal species. Here, we investigated the degree of co-diversification between Dictyocoela and Gammarus balcanicus, an amphipod with high degrees of ancient cryptic diversification and lineage endemism, by examining the genetic diversity of these parasites over the entire geographic range of the host. We hypothesised that the strong host diversification and vertical transmission of Dictyocoela would promote co-diversification.</p><p><strong>Results: </strong>Using the parasite SSU rDNA as a molecular marker, analyzing 2225 host specimens from 88 sites covering whole host range, we found 31 haplogroups of Dictyocoela, 30 of which were novel, belonging to four Dictyocoela species already known to infect other Gammarus spp. The relationships between Dictyocoela and gammarids is therefore ancient, with the speciation in parasites preceding those of the hosts. Each novel haplogroup was nevertheless specific to G. balcanicus, leaving the possibility for subsequent co-diversification process during host diversification. A Procrustean Approach to Co-phylogeny (PACo) analysis revealed that diversification of Dictyocoela was not random with respect to that of the host. We found high degrees of congruence between the diversification of G. balcanicus and that of Dictyocoela roeselum and D. muelleri. However, we also found some incongruences between host and Dictyocoela phylogenies, e.g. in D. duebenum, probably due to host shifts between different G. balcanicus cryptic lineages.</p><p><strong>Conclusion: </strong>The evolutionary history of Dictyocoela and Gammarus balcanicus represents an example of an overall host-parasite co-diversification, including cases of host shifts.</p>","PeriodicalId":9111,"journal":{"name":"BMC Evolutionary Biology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2020-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7659068/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38593926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-09DOI: 10.1186/s12862-020-01688-3
Perla Farhat, Sonja Siljak-Yakovlev, Nicolas Valentin, Carlos Fabregat, Silvia Lopez-Udias, Carlos Salazar-Mendias, Joaquín Altarejos, Robert P Adams
Background: Gene flow and polyploidy have been found to be important in Juniperus evolution. However, little evidence has been published elucidating the association of both phenomena in juniper taxa in the wild. Two main areas were studied in Spain (Eastern Iberian Range and Sierra de Baza) with both diploid and tetraploid taxa present in sympatry. Gene flow and ploidy level were assessed for these taxa and the resulted offspring.
Results: Twenty-two allo-triploid hybrids between J. sabina var. sabina and J. thurifera were found in the Eastern Iberian Range population. However, in the Sierra de Baza population no triploids were found. Instead, 18 allo-tetraploid hybrids between two tetraploid taxa: J. sabina var. balkanensis and J. thurifera were discovered. High genetic diversity was exhibited among the tetraploid hybrids at Sierra de Baza, in contrast to the genetically identical triploid hybrids at the Eastern Iberian Range; this suggests meiotic difficulties within the triploid hybrids. In addition, unidirectional gene flow was observed in both studied areas.
Conclusion: Polyploidy and hybridization can be complementary partners in the evolution of Juniperus taxa in sympatric occurrences. Juniperus was shown to be an ideal coniferous model to study these two phenomena, independently or in concert.
背景:基因流和多倍体被认为在杜松进化过程中非常重要。然而,很少有证据能阐明这两种现象在野生杜松类群中的关联。我们对西班牙的两个主要地区(伊比利亚山脉东部和巴扎山脉)进行了研究,这些地区同时存在二倍体和四倍体类群。对这些分类群及其后代的基因流和倍性水平进行了评估:结果:在伊比利亚山脉东部种群中发现了 22 个 sabina J. var. sabina 和 thurifera J. 的异源三倍体杂交种。然而,在 Sierra de Baza 种群中没有发现三倍体。相反,在两个四倍体类群中发现了 18 个异源四倍体杂交种:Balkanensis 和 J. thurifera 之间的 18 个异源四倍体杂交种。Sierra de Baza 的四倍体杂交种之间表现出高度的遗传多样性,与东伊比利亚山脉基因相同的三倍体杂交种形成鲜明对比;这表明三倍体杂交种内部存在减数分裂困难。此外,在两个研究地区都观察到了单向基因流动:结论:多倍体和杂交在瞻博树类群的同域进化过程中是互补的。研究表明,瞻博树是研究这两种现象独立或协同作用的理想针叶树模型。
{"title":"Gene flow between diploid and tetraploid junipers - two contrasting evolutionary pathways in two Juniperus populations.","authors":"Perla Farhat, Sonja Siljak-Yakovlev, Nicolas Valentin, Carlos Fabregat, Silvia Lopez-Udias, Carlos Salazar-Mendias, Joaquín Altarejos, Robert P Adams","doi":"10.1186/s12862-020-01688-3","DOIUrl":"10.1186/s12862-020-01688-3","url":null,"abstract":"<p><strong>Background: </strong>Gene flow and polyploidy have been found to be important in Juniperus evolution. However, little evidence has been published elucidating the association of both phenomena in juniper taxa in the wild. Two main areas were studied in Spain (Eastern Iberian Range and Sierra de Baza) with both diploid and tetraploid taxa present in sympatry. Gene flow and ploidy level were assessed for these taxa and the resulted offspring.</p><p><strong>Results: </strong>Twenty-two allo-triploid hybrids between J. sabina var. sabina and J. thurifera were found in the Eastern Iberian Range population. However, in the Sierra de Baza population no triploids were found. Instead, 18 allo-tetraploid hybrids between two tetraploid taxa: J. sabina var. balkanensis and J. thurifera were discovered. High genetic diversity was exhibited among the tetraploid hybrids at Sierra de Baza, in contrast to the genetically identical triploid hybrids at the Eastern Iberian Range; this suggests meiotic difficulties within the triploid hybrids. In addition, unidirectional gene flow was observed in both studied areas.</p><p><strong>Conclusion: </strong>Polyploidy and hybridization can be complementary partners in the evolution of Juniperus taxa in sympatric occurrences. Juniperus was shown to be an ideal coniferous model to study these two phenomena, independently or in concert.</p>","PeriodicalId":9111,"journal":{"name":"BMC Evolutionary Biology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2020-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7650182/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38586432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Background: Phenotypic convergence between distinct species provides an opportunity to examine the predictability of genetic evolution. Unrelated species sharing genetic underpinnings for phenotypic convergence suggests strong genetic constraints, and thus high predictability of evolution. However, there is no clear big picture of the genomic constraints on convergent evolution. Genome-based phylogenies have confirmed many cases of phenotypic convergence in birds, making them a good system for examining genetic constraints in phenotypic convergence. In this study, we used hierarchical genomic approaches to estimate genetic constraints in three convergent avian traits: nocturnality, raptorial behavior and foot-propelled diving.
Results: Phylogeny-based hypothesis tests and positive selection tests were applied to compare 16 avian genomes, representing 14 orders, and identify genes with strong convergence signals. We found 43 adaptively convergent genes (ACGs) associated with the three phenotypic convergence cases and assessed genetic constraints in all three cases, from (amino acid) site mutations to genetic pathways. We found that the avian orders shared few site mutations in the ACGs that contributed to the convergent phenotypes, and that these ACGs were not enriched in any genetic pathways. In addition, different pairs of orders with convergent foot-propelled diving or raptorial behaviors shared few ACGs. We also found that closely related orders that shared foot-propelled diving behavior did not share more ACGs than did distinct orders, suggesting that convergence among these orders could not be explained by their initial genomic backgrounds.
Conclusions: Our analyses of three avian convergence events suggest low constraints for phenotypic convergence across multiple genetic levels, implying that genetic evolution is unpredictable at the phylogenetic level of avian order. Ours is one of first studies to apply hierarchical genomic examination to multiple avian convergent cases to assess the genetic constraints in life history trait evolution.
{"title":"Avian phenotypic convergence is subject to low genetic constraints based on genomic evidence.","authors":"Yu-Chi Chen, Hao-Chih Kuo, Wen-Sui Lo, Chih-Ming Hung","doi":"10.1186/s12862-020-01711-7","DOIUrl":"10.1186/s12862-020-01711-7","url":null,"abstract":"<p><strong>Background: </strong>Phenotypic convergence between distinct species provides an opportunity to examine the predictability of genetic evolution. Unrelated species sharing genetic underpinnings for phenotypic convergence suggests strong genetic constraints, and thus high predictability of evolution. However, there is no clear big picture of the genomic constraints on convergent evolution. Genome-based phylogenies have confirmed many cases of phenotypic convergence in birds, making them a good system for examining genetic constraints in phenotypic convergence. In this study, we used hierarchical genomic approaches to estimate genetic constraints in three convergent avian traits: nocturnality, raptorial behavior and foot-propelled diving.</p><p><strong>Results: </strong>Phylogeny-based hypothesis tests and positive selection tests were applied to compare 16 avian genomes, representing 14 orders, and identify genes with strong convergence signals. We found 43 adaptively convergent genes (ACGs) associated with the three phenotypic convergence cases and assessed genetic constraints in all three cases, from (amino acid) site mutations to genetic pathways. We found that the avian orders shared few site mutations in the ACGs that contributed to the convergent phenotypes, and that these ACGs were not enriched in any genetic pathways. In addition, different pairs of orders with convergent foot-propelled diving or raptorial behaviors shared few ACGs. We also found that closely related orders that shared foot-propelled diving behavior did not share more ACGs than did distinct orders, suggesting that convergence among these orders could not be explained by their initial genomic backgrounds.</p><p><strong>Conclusions: </strong>Our analyses of three avian convergence events suggest low constraints for phenotypic convergence across multiple genetic levels, implying that genetic evolution is unpredictable at the phylogenetic level of avian order. Ours is one of first studies to apply hierarchical genomic examination to multiple avian convergent cases to assess the genetic constraints in life history trait evolution.</p>","PeriodicalId":9111,"journal":{"name":"BMC Evolutionary Biology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2020-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7648321/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38681343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-06DOI: 10.1186/s12862-020-01709-1
Leona Lovrenčić, Lena Bonassin, Ljudevit Luka Boštjančić, Martina Podnar, Mišel Jelić, Göran Klobučar, Martina Jaklič, Valentina Slavevska-Stamenković, Jelena Hinić, Ivana Maguire
Background: Austropotamobius torrentium is a freshwater crayfish species native to central and south-eastern Europe, with an intricate evolutionary history and the highest genetic diversity recorded in the northern-central Dinarides (NCD). Its populations are facing declines, both in number and size across its entire range. By extanding current knowledge on the genetic diversity of this species, we aim to assist conservation programmes. Multigene phylogenetic analyses were performed using different divergence time estimates based on mitochondrial and, for the first time, nuclear DNA markers on the largest data set analysed so far. In order to reassess taxonomic relationships within this species we applied several species delimitation methods and studied the meristic characters with the intention of finding features that would clearly separate stone crayfish belonging to different phylogroups.
Results: Our results confirmed the existence of high genetic diversity within A. torrentium, maintained in divergent phylogroups which have their own evolutionary dynamics. A new phylogroup in the Kordun region belonging to NCD has also been discovered. Due to the incongruence between implemented species delimitation approaches and the lack of any morphological characters conserved within lineages, we are of the opinion that phylogroups recovered on mitochondrial and nuclear DNA are cryptic subspecies and distinct evolutionary significant units.
Conclusions: Geographically and genetically isolated phylogroups represent the evolutionary legacy of A. torrentium and are highly relevant for conservation due to their evolutionary distinctiveness and restricted distribution.
{"title":"New insights into the genetic diversity of the stone crayfish: taxonomic and conservation implications.","authors":"Leona Lovrenčić, Lena Bonassin, Ljudevit Luka Boštjančić, Martina Podnar, Mišel Jelić, Göran Klobučar, Martina Jaklič, Valentina Slavevska-Stamenković, Jelena Hinić, Ivana Maguire","doi":"10.1186/s12862-020-01709-1","DOIUrl":"https://doi.org/10.1186/s12862-020-01709-1","url":null,"abstract":"<p><strong>Background: </strong>Austropotamobius torrentium is a freshwater crayfish species native to central and south-eastern Europe, with an intricate evolutionary history and the highest genetic diversity recorded in the northern-central Dinarides (NCD). Its populations are facing declines, both in number and size across its entire range. By extanding current knowledge on the genetic diversity of this species, we aim to assist conservation programmes. Multigene phylogenetic analyses were performed using different divergence time estimates based on mitochondrial and, for the first time, nuclear DNA markers on the largest data set analysed so far. In order to reassess taxonomic relationships within this species we applied several species delimitation methods and studied the meristic characters with the intention of finding features that would clearly separate stone crayfish belonging to different phylogroups.</p><p><strong>Results: </strong>Our results confirmed the existence of high genetic diversity within A. torrentium, maintained in divergent phylogroups which have their own evolutionary dynamics. A new phylogroup in the Kordun region belonging to NCD has also been discovered. Due to the incongruence between implemented species delimitation approaches and the lack of any morphological characters conserved within lineages, we are of the opinion that phylogroups recovered on mitochondrial and nuclear DNA are cryptic subspecies and distinct evolutionary significant units.</p><p><strong>Conclusions: </strong>Geographically and genetically isolated phylogroups represent the evolutionary legacy of A. torrentium and are highly relevant for conservation due to their evolutionary distinctiveness and restricted distribution.</p>","PeriodicalId":9111,"journal":{"name":"BMC Evolutionary Biology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2020-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s12862-020-01709-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38578035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-04DOI: 10.1186/s12862-020-01699-0
Nikolaus U Szucsich, Daniela Bartel, Alexander Blanke, Alexander Böhm, Alexander Donath, Makiko Fukui, Simon Grove, Shanlin Liu, Oliver Macek, Ryuichiro Machida, Bernhard Misof, Yasutaka Nakagaki, Lars Podsiadlowski, Kaoru Sekiya, Shigekazu Tomizuka, Björn M Von Reumont, Robert M Waterhouse, Manfred Walzl, Guanliang Meng, Xin Zhou, Günther Pass, Karen Meusemann
Background: Phylogenetic relationships among the myriapod subgroups Chilopoda, Diplopoda, Symphyla and Pauropoda are still not robustly resolved. The first phylogenomic study covering all subgroups resolved phylogenetic relationships congruently to morphological evidence but is in conflict with most previously published phylogenetic trees based on diverse molecular data. Outgroup choice and long-branch attraction effects were stated as possible explanations for these incongruencies. In this study, we addressed these issues by extending the myriapod and outgroup taxon sampling using transcriptome data.
Results: We generated new transcriptome data of 42 panarthropod species, including all four myriapod subgroups and additional outgroup taxa. Our taxon sampling was complemented by published transcriptome and genome data resulting in a supermatrix covering 59 species. We compiled two data sets, the first with a full coverage of genes per species (292 single-copy protein-coding genes), the second with a less stringent coverage (988 genes). We inferred phylogenetic relationships among myriapods using different data types, tree inference, and quartet computation approaches. Our results unambiguously support monophyletic Mandibulata and Myriapoda. Our analyses clearly showed that there is strong signal for a single unrooted topology, but a sensitivity of the position of the internal root on the choice of outgroups. However, we observe strong evidence for a clade Pauropoda+Symphyla, as well as for a clade Chilopoda+Diplopoda.
Conclusions: Our best quartet topology is incongruent with current morphological phylogenies which were supported in another phylogenomic study. AU tests and quartet mapping reject the quartet topology congruent to trees inferred with morphological characters. Moreover, quartet mapping shows that confounding signal present in the data set is sufficient to explain the weak signal for the quartet topology derived from morphological characters. Although outgroup choice affects results, our study could narrow possible trees to derivatives of a single quartet topology. For highly disputed relationships, we propose to apply a series of tests (AU and quartet mapping), since results of such tests allow to narrow down possible relationships and to rule out confounding signal.
{"title":"Four myriapod relatives - but who are sisters? No end to debates on relationships among the four major myriapod subgroups.","authors":"Nikolaus U Szucsich, Daniela Bartel, Alexander Blanke, Alexander Böhm, Alexander Donath, Makiko Fukui, Simon Grove, Shanlin Liu, Oliver Macek, Ryuichiro Machida, Bernhard Misof, Yasutaka Nakagaki, Lars Podsiadlowski, Kaoru Sekiya, Shigekazu Tomizuka, Björn M Von Reumont, Robert M Waterhouse, Manfred Walzl, Guanliang Meng, Xin Zhou, Günther Pass, Karen Meusemann","doi":"10.1186/s12862-020-01699-0","DOIUrl":"https://doi.org/10.1186/s12862-020-01699-0","url":null,"abstract":"<p><strong>Background: </strong>Phylogenetic relationships among the myriapod subgroups Chilopoda, Diplopoda, Symphyla and Pauropoda are still not robustly resolved. The first phylogenomic study covering all subgroups resolved phylogenetic relationships congruently to morphological evidence but is in conflict with most previously published phylogenetic trees based on diverse molecular data. Outgroup choice and long-branch attraction effects were stated as possible explanations for these incongruencies. In this study, we addressed these issues by extending the myriapod and outgroup taxon sampling using transcriptome data.</p><p><strong>Results: </strong>We generated new transcriptome data of 42 panarthropod species, including all four myriapod subgroups and additional outgroup taxa. Our taxon sampling was complemented by published transcriptome and genome data resulting in a supermatrix covering 59 species. We compiled two data sets, the first with a full coverage of genes per species (292 single-copy protein-coding genes), the second with a less stringent coverage (988 genes). We inferred phylogenetic relationships among myriapods using different data types, tree inference, and quartet computation approaches. Our results unambiguously support monophyletic Mandibulata and Myriapoda. Our analyses clearly showed that there is strong signal for a single unrooted topology, but a sensitivity of the position of the internal root on the choice of outgroups. However, we observe strong evidence for a clade Pauropoda+Symphyla, as well as for a clade Chilopoda+Diplopoda.</p><p><strong>Conclusions: </strong>Our best quartet topology is incongruent with current morphological phylogenies which were supported in another phylogenomic study. AU tests and quartet mapping reject the quartet topology congruent to trees inferred with morphological characters. Moreover, quartet mapping shows that confounding signal present in the data set is sufficient to explain the weak signal for the quartet topology derived from morphological characters. Although outgroup choice affects results, our study could narrow possible trees to derivatives of a single quartet topology. For highly disputed relationships, we propose to apply a series of tests (AU and quartet mapping), since results of such tests allow to narrow down possible relationships and to rule out confounding signal.</p>","PeriodicalId":9111,"journal":{"name":"BMC Evolutionary Biology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2020-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s12862-020-01699-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38670705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-04DOI: 10.1186/s12862-020-01707-3
Olaya Rendueles, Gregory J Velicer
Background: Evolution in one selective environment often latently generates phenotypic change that is manifested only later in different environments, but the complexity of behavior important to fitness in the original environment might influence the character of such latent-phenotype evolution. Using Myxococcus xanthus, a bacterium possessing two motility systems differing in effectiveness on hard vs. soft surfaces, we test (i) whether and how evolution while swarming on one surface-the selective surface-latently alters motility on the alternative surface type and (ii) whether patterns of such latent-phenotype evolution depend on the complexity of ancestral motility, specific ancestral motility genotypes and/or the selective surface of evolution. We analysze an experiment in which populations established from three ancestral genotypes-one with both motility systems intact and two others with one system debilitated-evolved while swarming across either hard or soft agar in six evolutionary treatments. We then compare motility-phenotype patterns across selective vs. alternative surface types.
Results: Latent motility evolution was pervasive but varied in character as a function of the presence of one or two functional motility systems and, for some individual-treatment comparisons, the specific ancestral genotype and/or selective surface. Swarming rates on alternative vs. selective surfaces were positively correlated generally among populations with one functional motility system but not among those with two. This suggests that opportunities for pleiotropy and epistasis generated by increased genetic complexity underlying behavior can alter the character of latent-phenotype evolution. No tradeoff between motility performance across surface types was detected in the dual-system treatments, even after adaptation on a surface on which one motility system dominates strongly over the other in driving movement, but latent-phenotype evolution was instead idiosyncratic in these treatments. We further find that the magnitude of stochastic diversification at alternative-surface swarming among replicate populations greatly exceeded diversification of selective-surface swarming within some treatments and varied across treatments.
Conclusion: Collectively, our results suggest that increases in the genetic and mechanistic complexity of behavior can increase the complexity of latent-phenotype evolution outcomes and illustrate that diversification manifested during evolution in one environment can be augmented greatly by diversification of latent phenotypes manifested later.
{"title":"Hidden paths to endless forms most wonderful: Complexity of bacterial motility shapes diversification of latent phenotypes.","authors":"Olaya Rendueles, Gregory J Velicer","doi":"10.1186/s12862-020-01707-3","DOIUrl":"https://doi.org/10.1186/s12862-020-01707-3","url":null,"abstract":"<p><strong>Background: </strong>Evolution in one selective environment often latently generates phenotypic change that is manifested only later in different environments, but the complexity of behavior important to fitness in the original environment might influence the character of such latent-phenotype evolution. Using Myxococcus xanthus, a bacterium possessing two motility systems differing in effectiveness on hard vs. soft surfaces, we test (i) whether and how evolution while swarming on one surface-the selective surface-latently alters motility on the alternative surface type and (ii) whether patterns of such latent-phenotype evolution depend on the complexity of ancestral motility, specific ancestral motility genotypes and/or the selective surface of evolution. We analysze an experiment in which populations established from three ancestral genotypes-one with both motility systems intact and two others with one system debilitated-evolved while swarming across either hard or soft agar in six evolutionary treatments. We then compare motility-phenotype patterns across selective vs. alternative surface types.</p><p><strong>Results: </strong>Latent motility evolution was pervasive but varied in character as a function of the presence of one or two functional motility systems and, for some individual-treatment comparisons, the specific ancestral genotype and/or selective surface. Swarming rates on alternative vs. selective surfaces were positively correlated generally among populations with one functional motility system but not among those with two. This suggests that opportunities for pleiotropy and epistasis generated by increased genetic complexity underlying behavior can alter the character of latent-phenotype evolution. No tradeoff between motility performance across surface types was detected in the dual-system treatments, even after adaptation on a surface on which one motility system dominates strongly over the other in driving movement, but latent-phenotype evolution was instead idiosyncratic in these treatments. We further find that the magnitude of stochastic diversification at alternative-surface swarming among replicate populations greatly exceeded diversification of selective-surface swarming within some treatments and varied across treatments.</p><p><strong>Conclusion: </strong>Collectively, our results suggest that increases in the genetic and mechanistic complexity of behavior can increase the complexity of latent-phenotype evolution outcomes and illustrate that diversification manifested during evolution in one environment can be augmented greatly by diversification of latent phenotypes manifested later.</p>","PeriodicalId":9111,"journal":{"name":"BMC Evolutionary Biology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2020-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s12862-020-01707-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38670707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-03DOI: 10.1186/s12862-020-01710-8
Wan Li, Yue Chen, Minghui Ye, Haibin Lu, Dongdong Wang, Qin Chen
Background: Plants are easily affected by temperature variations, and high temperature (heat stress) and low temperature (cold stress) will lead to poor plant development and reduce crop yields. Therefore, it is very important to identify resistance genes for improving the ability of plants to resist heat stress or cold stress by using modern biotechnology. Members of the C-repeat binding factor/Dehydration responsive element-binding 1 (CBF/DREB1) protein family are related to the stress resistance of many plant species. These proteins affect the growth and development of plants and play vital roles during environmental stress (cold, heat, drought, salt, etc.). In this study, we identified CBF/DREB1 genes from 43 plant species (including algae, moss, ferns, gymnosperms, angiosperms) by using bioinformatic methods to clarify the characteristics of the CBF/DREB1 protein family members and their functions in potato under heat and cold stresses.
Results: In this study, we identified 292 CBF/DREB1 proteins from 43 plant species. However, no CBF/DREB1 protein was found in algae, moss, ferns, or gymnosperms; members of this protein family exist only in angiosperms. Phylogenetic analysis of all the CBF/DREB1 proteins revealed five independent groups. Among them, the genes of group I do not exist in eudicots and are found only in monocots, indicating that these genes have a special effect on monocots. The analysis of motifs, gene duplication events, and the expression data from the PGSC website revealed the gene structures, evolutionary relationships, and expression patterns of the CBF/DREB1 proteins. In addition, analysis of the transcript levels of the 8 CBF/DREB1 genes in potato (Solanum tuberosum) under low-temperature and high-temperature stresses showed that these genes were related to temperature stresses. In particular, the expression levels of StCBF3 and StCBF4 in the leaves, stems, and roots significantly increased under high-temperature conditions, which suggested that StCBF3 and StCBF4 may be closely related to heat tolerance in potato.
Conclusion: Overall, members of the CBF/DREB1 protein family exist only in angiosperms and plays an important role in the growth and development of plants. In addition, the CBF/DREB1 protein family is related to the heat and cold resistance of potato. Our research revealed the evolution of the CBF/DREB1 family, and is useful for studying the precise functions of the CBF/DREB1 proteins when the plants are developing and are under temperature stress.
{"title":"Evolutionary history of the C-repeat binding factor/dehydration-responsive element-binding 1 (CBF/DREB1) protein family in 43 plant species and characterization of CBF/DREB1 proteins in Solanum tuberosum.","authors":"Wan Li, Yue Chen, Minghui Ye, Haibin Lu, Dongdong Wang, Qin Chen","doi":"10.1186/s12862-020-01710-8","DOIUrl":"https://doi.org/10.1186/s12862-020-01710-8","url":null,"abstract":"<p><strong>Background: </strong>Plants are easily affected by temperature variations, and high temperature (heat stress) and low temperature (cold stress) will lead to poor plant development and reduce crop yields. Therefore, it is very important to identify resistance genes for improving the ability of plants to resist heat stress or cold stress by using modern biotechnology. Members of the C-repeat binding factor/Dehydration responsive element-binding 1 (CBF/DREB1) protein family are related to the stress resistance of many plant species. These proteins affect the growth and development of plants and play vital roles during environmental stress (cold, heat, drought, salt, etc.). In this study, we identified CBF/DREB1 genes from 43 plant species (including algae, moss, ferns, gymnosperms, angiosperms) by using bioinformatic methods to clarify the characteristics of the CBF/DREB1 protein family members and their functions in potato under heat and cold stresses.</p><p><strong>Results: </strong>In this study, we identified 292 CBF/DREB1 proteins from 43 plant species. However, no CBF/DREB1 protein was found in algae, moss, ferns, or gymnosperms; members of this protein family exist only in angiosperms. Phylogenetic analysis of all the CBF/DREB1 proteins revealed five independent groups. Among them, the genes of group I do not exist in eudicots and are found only in monocots, indicating that these genes have a special effect on monocots. The analysis of motifs, gene duplication events, and the expression data from the PGSC website revealed the gene structures, evolutionary relationships, and expression patterns of the CBF/DREB1 proteins. In addition, analysis of the transcript levels of the 8 CBF/DREB1 genes in potato (Solanum tuberosum) under low-temperature and high-temperature stresses showed that these genes were related to temperature stresses. In particular, the expression levels of StCBF3 and StCBF4 in the leaves, stems, and roots significantly increased under high-temperature conditions, which suggested that StCBF3 and StCBF4 may be closely related to heat tolerance in potato.</p><p><strong>Conclusion: </strong>Overall, members of the CBF/DREB1 protein family exist only in angiosperms and plays an important role in the growth and development of plants. In addition, the CBF/DREB1 protein family is related to the heat and cold resistance of potato. Our research revealed the evolution of the CBF/DREB1 family, and is useful for studying the precise functions of the CBF/DREB1 proteins when the plants are developing and are under temperature stress.</p>","PeriodicalId":9111,"journal":{"name":"BMC Evolutionary Biology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2020-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s12862-020-01710-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38562934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-03DOI: 10.1186/s12862-020-01713-5
Ryo Kakioka, Seiichi Mori, Tomoyuki Kokita, Takuya K Hosoki, Atsushi J Nagano, Asano Ishikawa, Manabu Kume, Atsushi Toyoda, Jun Kitano
Background: The three-spined stickleback (Gasterosteus aculeatus) is a remarkable system to study the genetic mechanisms underlying parallel evolution during the transition from marine to freshwater habitats. Although the majority of previous studies on the parallel evolution of sticklebacks have mainly focused on postglacial freshwater populations in the Pacific Northwest of North America and northern Europe, we recently use Japanese stickleback populations for investigating shared and unique features of adaptation and speciation between geographically distant populations. However, we currently lack a comprehensive phylogeny of the Japanese three-spined sticklebacks, despite the fact that a good phylogeny is essential for any evolutionary and ecological studies. Here, we conducted a phylogenomic analysis of the three-spined stickleback in the Japanese Archipelago.
Results: We found that freshwater colonization occurred in multiple waves, each of which may reflect different interglacial isolations. Some of the oldest freshwater populations from the central regions of the mainland of Japan (hariyo populations) were estimated to colonize freshwater approximately 170,000 years ago. The next wave of colonization likely occurred approximately 100,000 years ago. The inferred origins of several human-introduced populations showed that introduction occurred mainly from nearby habitats. We also found a new habitat of the three-spined stickleback sympatric with the Japan Sea stickleback (Gasterosteus nipponicus).
Conclusions: These Japanese stickleback systems differ from those in the Pacific Northwest of North America and northern Europe in terms of divergence time and history. Stickleback populations in the Japanese Archipelago offer valuable opportunities to study diverse evolutionary processes in historical and contemporary timescales.
{"title":"Multiple waves of freshwater colonization of the three-spined stickleback in the Japanese Archipelago.","authors":"Ryo Kakioka, Seiichi Mori, Tomoyuki Kokita, Takuya K Hosoki, Atsushi J Nagano, Asano Ishikawa, Manabu Kume, Atsushi Toyoda, Jun Kitano","doi":"10.1186/s12862-020-01713-5","DOIUrl":"https://doi.org/10.1186/s12862-020-01713-5","url":null,"abstract":"<p><strong>Background: </strong>The three-spined stickleback (Gasterosteus aculeatus) is a remarkable system to study the genetic mechanisms underlying parallel evolution during the transition from marine to freshwater habitats. Although the majority of previous studies on the parallel evolution of sticklebacks have mainly focused on postglacial freshwater populations in the Pacific Northwest of North America and northern Europe, we recently use Japanese stickleback populations for investigating shared and unique features of adaptation and speciation between geographically distant populations. However, we currently lack a comprehensive phylogeny of the Japanese three-spined sticklebacks, despite the fact that a good phylogeny is essential for any evolutionary and ecological studies. Here, we conducted a phylogenomic analysis of the three-spined stickleback in the Japanese Archipelago.</p><p><strong>Results: </strong>We found that freshwater colonization occurred in multiple waves, each of which may reflect different interglacial isolations. Some of the oldest freshwater populations from the central regions of the mainland of Japan (hariyo populations) were estimated to colonize freshwater approximately 170,000 years ago. The next wave of colonization likely occurred approximately 100,000 years ago. The inferred origins of several human-introduced populations showed that introduction occurred mainly from nearby habitats. We also found a new habitat of the three-spined stickleback sympatric with the Japan Sea stickleback (Gasterosteus nipponicus).</p><p><strong>Conclusions: </strong>These Japanese stickleback systems differ from those in the Pacific Northwest of North America and northern Europe in terms of divergence time and history. Stickleback populations in the Japanese Archipelago offer valuable opportunities to study diverse evolutionary processes in historical and contemporary timescales.</p>","PeriodicalId":9111,"journal":{"name":"BMC Evolutionary Biology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2020-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s12862-020-01713-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38562935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Background: The Drosophilidae family is traditionally divided into two subfamilies: Drosophilinae and Steganinae. This division is based on morphological characters, and the two subfamilies have been treated as monophyletic in most of the literature, but some molecular phylogenies have suggested Steganinae to be paraphyletic. To test the paraphyletic-Steganinae hypothesis, here, we used genomic sequences of eight Drosophilidae (three Steganinae and five Drosophilinae) and two Ephydridae (outgroup) species and inferred the phylogeny for the group based on a dataset of 1,028 orthologous genes present in all species (> 1,000,000 bp). This dataset includes three genera that broke the monophyly of the subfamilies in previous works. To investigate possible biases introduced by small sample sizes and automatic gene annotation, we used the same methods to infer species trees from a set of 10 manually annotated genes that are commonly used in phylogenetics.
Results: Most of the 1,028 gene trees depicted Steganinae as paraphyletic with distinct topologies, but the most common topology depicted it as monophyletic (43.7% of the gene trees). Despite the high levels of gene tree heterogeneity observed, species tree inference in ASTRAL, in PhyloNet, and with the concatenation approach strongly supported the monophyly of both subfamilies for the 1,028-gene dataset. However, when using the concatenation approach to infer a species tree from the smaller set of 10 genes, we recovered Steganinae as a paraphyletic group. The pattern of gene tree heterogeneity was asymmetrical and thus could not be explained solely by incomplete lineage sorting (ILS).
Conclusions: Steganinae was clearly a monophyletic group in the dataset that we analyzed. In addition to ILS, gene tree discordance was possibly the result of introgression, suggesting complex branching processes during the early evolution of Drosophilidae with short speciation intervals and gene flow. Our study highlights the importance of genomic data in elucidating contentious phylogenetic relationships and suggests that phylogenetic inference for drosophilids based on small molecular datasets should be performed cautiously. Finally, we suggest an approach for the correction and cleaning of BUSCO-derived genomic datasets that will be useful to other researchers planning to use this tool for phylogenomic studies.
{"title":"A phylogenomic study of Steganinae fruit flies (Diptera: Drosophilidae): strong gene tree heterogeneity and evidence for monophyly.","authors":"Guilherme Rezende Dias, Eduardo Guimarães Dupim, Thyago Vanderlinde, Beatriz Mello, Antonio Bernardo Carvalho","doi":"10.1186/s12862-020-01703-7","DOIUrl":"https://doi.org/10.1186/s12862-020-01703-7","url":null,"abstract":"<p><strong>Background: </strong>The Drosophilidae family is traditionally divided into two subfamilies: Drosophilinae and Steganinae. This division is based on morphological characters, and the two subfamilies have been treated as monophyletic in most of the literature, but some molecular phylogenies have suggested Steganinae to be paraphyletic. To test the paraphyletic-Steganinae hypothesis, here, we used genomic sequences of eight Drosophilidae (three Steganinae and five Drosophilinae) and two Ephydridae (outgroup) species and inferred the phylogeny for the group based on a dataset of 1,028 orthologous genes present in all species (> 1,000,000 bp). This dataset includes three genera that broke the monophyly of the subfamilies in previous works. To investigate possible biases introduced by small sample sizes and automatic gene annotation, we used the same methods to infer species trees from a set of 10 manually annotated genes that are commonly used in phylogenetics.</p><p><strong>Results: </strong>Most of the 1,028 gene trees depicted Steganinae as paraphyletic with distinct topologies, but the most common topology depicted it as monophyletic (43.7% of the gene trees). Despite the high levels of gene tree heterogeneity observed, species tree inference in ASTRAL, in PhyloNet, and with the concatenation approach strongly supported the monophyly of both subfamilies for the 1,028-gene dataset. However, when using the concatenation approach to infer a species tree from the smaller set of 10 genes, we recovered Steganinae as a paraphyletic group. The pattern of gene tree heterogeneity was asymmetrical and thus could not be explained solely by incomplete lineage sorting (ILS).</p><p><strong>Conclusions: </strong>Steganinae was clearly a monophyletic group in the dataset that we analyzed. In addition to ILS, gene tree discordance was possibly the result of introgression, suggesting complex branching processes during the early evolution of Drosophilidae with short speciation intervals and gene flow. Our study highlights the importance of genomic data in elucidating contentious phylogenetic relationships and suggests that phylogenetic inference for drosophilids based on small molecular datasets should be performed cautiously. Finally, we suggest an approach for the correction and cleaning of BUSCO-derived genomic datasets that will be useful to other researchers planning to use this tool for phylogenomic studies.</p>","PeriodicalId":9111,"journal":{"name":"BMC Evolutionary Biology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2020-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s12862-020-01703-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38557779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-31DOI: 10.1186/s12862-020-01712-6
Xianzong Wang, Junli Yan
Background: EP300 is a conserved protein in vertebrates, which serves as a key mediator of cellular homeostasis. Mutations and dysregulation of EP300 give rise to severe human developmental disorders and malignancy. Danio rerio is a promising model organism to study EP300 related diseases and drugs; however, the effect of EP300 duplicates derived from teleost-specific whole genome duplication should not just be neglected.
Results: In this study, we obtained EP300 protein sequences of representative teleosts, mammals and sauropsids, with which we inferred a highly supported maximum likelihood tree. We observed that Ep300 duplicates (Ep300a and Ep300b) were widely retained in teleosts and universally expressed in a variety of tissues. Consensus sequences of Ep300a and Ep300b had exactly the same distribution of conserved domains, suggesting that their functions should still be largely overlapped. We analyzed the molecular evolution of Ep300 duplicates in teleosts, using branch-site models, clade models and site models. The results showed that both duplicates were subject to strong positive selection; however, for an extant species, generally at most one copy was under positive selection. At the clade level, there were evident positive correlations between evolutionary rates, the number of positively selected sites and gene expression levels. In Ostariophysi, Ep300a were under stronger positive selection than Ep300b; in Neoteleostei, another species-rich teleost clade, the contrary was the case. We also modeled 3D structures of zf-TAZ domain and its flanking regions of Ep300a and Ep300b of D. rerio and Oryzias latipes and found that in either species the faster evolving copy had more short helixes.
Conclusions: Collectively, the two copies of Ep300 have undoubtedly experienced directional divergence in main teleost clades. The divergence of EP300 between teleosts and mammals should be greater than the divergence between different teleost clades. Further studies are needed to clarify to what extent the EP300 involved regulatory network has diverged between teleosts and mammals, which would also help explain the huge success of teleosts.
{"title":"Directional divergence of Ep300 duplicates in teleosts and its implications.","authors":"Xianzong Wang, Junli Yan","doi":"10.1186/s12862-020-01712-6","DOIUrl":"https://doi.org/10.1186/s12862-020-01712-6","url":null,"abstract":"<p><strong>Background: </strong>EP300 is a conserved protein in vertebrates, which serves as a key mediator of cellular homeostasis. Mutations and dysregulation of EP300 give rise to severe human developmental disorders and malignancy. Danio rerio is a promising model organism to study EP300 related diseases and drugs; however, the effect of EP300 duplicates derived from teleost-specific whole genome duplication should not just be neglected.</p><p><strong>Results: </strong>In this study, we obtained EP300 protein sequences of representative teleosts, mammals and sauropsids, with which we inferred a highly supported maximum likelihood tree. We observed that Ep300 duplicates (Ep300a and Ep300b) were widely retained in teleosts and universally expressed in a variety of tissues. Consensus sequences of Ep300a and Ep300b had exactly the same distribution of conserved domains, suggesting that their functions should still be largely overlapped. We analyzed the molecular evolution of Ep300 duplicates in teleosts, using branch-site models, clade models and site models. The results showed that both duplicates were subject to strong positive selection; however, for an extant species, generally at most one copy was under positive selection. At the clade level, there were evident positive correlations between evolutionary rates, the number of positively selected sites and gene expression levels. In Ostariophysi, Ep300a were under stronger positive selection than Ep300b; in Neoteleostei, another species-rich teleost clade, the contrary was the case. We also modeled 3D structures of zf-TAZ domain and its flanking regions of Ep300a and Ep300b of D. rerio and Oryzias latipes and found that in either species the faster evolving copy had more short helixes.</p><p><strong>Conclusions: </strong>Collectively, the two copies of Ep300 have undoubtedly experienced directional divergence in main teleost clades. The divergence of EP300 between teleosts and mammals should be greater than the divergence between different teleost clades. Further studies are needed to clarify to what extent the EP300 involved regulatory network has diverged between teleosts and mammals, which would also help explain the huge success of teleosts.</p>","PeriodicalId":9111,"journal":{"name":"BMC Evolutionary Biology","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2020-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s12862-020-01712-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38550114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}