Pub Date : 2020-10-02DOI: 10.1186/s12862-020-01693-6
R G Loosemore, S D Matthaei, T C Stanger
The primordial eye field of the vertebrate embryo is a single entity of retinal progenitor cells spanning the anterior neural plate before bifurcating to form bilateral optic vesicles. Here we review fate mapping data from zebrafish suggesting that prior to evagination of the optic vesicles the eye field may undergo a Maypole-plait migration of progenitor cells through the midline influenced by the anteriorly subducting diencephalon. Such an enigmatic translocation of scaffolding progenitors could have evolutionary significance if pointing, by way of homology, to an ancient mechanism for transition of the single eye field in chordates to contralateral eye fields in vertebrates.
{"title":"An enigmatic translocation of the vertebrate primordial eye field.","authors":"R G Loosemore, S D Matthaei, T C Stanger","doi":"10.1186/s12862-020-01693-6","DOIUrl":"https://doi.org/10.1186/s12862-020-01693-6","url":null,"abstract":"<p><p>The primordial eye field of the vertebrate embryo is a single entity of retinal progenitor cells spanning the anterior neural plate before bifurcating to form bilateral optic vesicles. Here we review fate mapping data from zebrafish suggesting that prior to evagination of the optic vesicles the eye field may undergo a Maypole-plait migration of progenitor cells through the midline influenced by the anteriorly subducting diencephalon. Such an enigmatic translocation of scaffolding progenitors could have evolutionary significance if pointing, by way of homology, to an ancient mechanism for transition of the single eye field in chordates to contralateral eye fields in vertebrates.</p>","PeriodicalId":9111,"journal":{"name":"BMC Evolutionary Biology","volume":"20 1","pages":"129"},"PeriodicalIF":3.4,"publicationDate":"2020-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s12862-020-01693-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38451142","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 : 2020-09-25DOI: 10.1186/s12862-020-01685-6
Tuc H M Nguyen, Sargunvir Sondhi, Andrew Ziesel, Swati Paliwal, Heather L Fiumera
Background: Mitochondrial function requires numerous genetic interactions between mitochondrial- and nuclear- encoded genes. While selection for optimal mitonuclear interactions should result in coevolution between both genomes, evidence for mitonuclear coadaptation is challenging to document. Genetic models where mitonuclear interactions can be explored are needed.
Results: We systematically exchanged mtDNAs between 15 Saccharomyces cerevisiae isolates from a variety of ecological niches to create 225 unique mitochondrial-nuclear genotypes. Analysis of phenotypic profiles confirmed that environmentally-sensitive interactions between mitochondrial and nuclear genotype contributed to growth differences. Exchanges of mtDNAs between strains of the same or different clades were just as likely to demonstrate mitonuclear epistasis although epistatic effect sizes increased with genetic distances. Strains with their original mtDNAs were more fit than strains with synthetic mitonuclear combinations when grown in media that resembled isolation habitats.
Conclusions: This study shows that natural variation in mitonuclear interactions contributes to fitness landscapes. Multiple examples of coadapted mitochondrial-nuclear genotypes suggest that selection for mitonuclear interactions may play a role in helping yeasts adapt to novel environments and promote coevolution.
{"title":"Mitochondrial-nuclear coadaptation revealed through mtDNA replacements in Saccharomyces cerevisiae.","authors":"Tuc H M Nguyen, Sargunvir Sondhi, Andrew Ziesel, Swati Paliwal, Heather L Fiumera","doi":"10.1186/s12862-020-01685-6","DOIUrl":"10.1186/s12862-020-01685-6","url":null,"abstract":"<p><strong>Background: </strong>Mitochondrial function requires numerous genetic interactions between mitochondrial- and nuclear- encoded genes. While selection for optimal mitonuclear interactions should result in coevolution between both genomes, evidence for mitonuclear coadaptation is challenging to document. Genetic models where mitonuclear interactions can be explored are needed.</p><p><strong>Results: </strong>We systematically exchanged mtDNAs between 15 Saccharomyces cerevisiae isolates from a variety of ecological niches to create 225 unique mitochondrial-nuclear genotypes. Analysis of phenotypic profiles confirmed that environmentally-sensitive interactions between mitochondrial and nuclear genotype contributed to growth differences. Exchanges of mtDNAs between strains of the same or different clades were just as likely to demonstrate mitonuclear epistasis although epistatic effect sizes increased with genetic distances. Strains with their original mtDNAs were more fit than strains with synthetic mitonuclear combinations when grown in media that resembled isolation habitats.</p><p><strong>Conclusions: </strong>This study shows that natural variation in mitonuclear interactions contributes to fitness landscapes. Multiple examples of coadapted mitochondrial-nuclear genotypes suggest that selection for mitonuclear interactions may play a role in helping yeasts adapt to novel environments and promote coevolution.</p>","PeriodicalId":9111,"journal":{"name":"BMC Evolutionary Biology","volume":"20 1","pages":"128"},"PeriodicalIF":3.4,"publicationDate":"2020-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7517635/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38521458","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 : 2020-09-24DOI: 10.1186/s12862-020-01692-7
Pengjuan Zu, Florian P Schiestl, Daniel Gervasi, Xin Li, Daniel Runcie, Frédéric Guillaume
Background: Angiosperms employ an astonishing variety of visual and olfactory floral signals that are generally thought to evolve under natural selection. Those morphological and chemical traits can form highly correlated sets of traits. It is not always clear which of these are used by pollinators as primary targets of selection and which would be indirectly selected by being linked to those primary targets. Quantitative genetics tools for predicting multiple traits response to selection have been developed since long and have advanced our understanding of evolution of genetically correlated traits in various biological systems. We use these tools to predict the evolutionary trajectories of floral traits and understand the selection pressures acting on them.
Results: We used data from an artificial selection and a pollinator (bumblebee, hoverfly) evolution experiment with fast cycling Brassica rapa plants to predict evolutionary changes of 12 floral volatiles and 4 morphological floral traits in response to selection. Using the observed selection gradients and the genetic variance-covariance matrix (G-matrix) of the traits, we showed that the observed responses of most floral traits including volatiles were predicted in the right direction in both artificial- and bumblebee-selection experiment. Genetic covariance had a mix of constraining and facilitating effects on evolutionary responses. We further revealed that G-matrices also evolved in the selection processes.
Conclusions: Overall, our integrative study shows that floral signals, especially volatiles, evolve under selection in a mostly predictable way, at least during short term evolution. Evolutionary constraints stemming from genetic covariance affected traits evolutionary trajectories and thus it is important to include genetic covariance for predicting the evolutionary changes of a comprehensive suite of traits. Other processes such as resource limitation and selfing also need to be considered for a better understanding of floral trait evolution.
{"title":"Floral signals evolve in a predictable way under artificial and pollinator selection in Brassica rapa.","authors":"Pengjuan Zu, Florian P Schiestl, Daniel Gervasi, Xin Li, Daniel Runcie, Frédéric Guillaume","doi":"10.1186/s12862-020-01692-7","DOIUrl":"10.1186/s12862-020-01692-7","url":null,"abstract":"<p><strong>Background: </strong>Angiosperms employ an astonishing variety of visual and olfactory floral signals that are generally thought to evolve under natural selection. Those morphological and chemical traits can form highly correlated sets of traits. It is not always clear which of these are used by pollinators as primary targets of selection and which would be indirectly selected by being linked to those primary targets. Quantitative genetics tools for predicting multiple traits response to selection have been developed since long and have advanced our understanding of evolution of genetically correlated traits in various biological systems. We use these tools to predict the evolutionary trajectories of floral traits and understand the selection pressures acting on them.</p><p><strong>Results: </strong>We used data from an artificial selection and a pollinator (bumblebee, hoverfly) evolution experiment with fast cycling Brassica rapa plants to predict evolutionary changes of 12 floral volatiles and 4 morphological floral traits in response to selection. Using the observed selection gradients and the genetic variance-covariance matrix (G-matrix) of the traits, we showed that the observed responses of most floral traits including volatiles were predicted in the right direction in both artificial- and bumblebee-selection experiment. Genetic covariance had a mix of constraining and facilitating effects on evolutionary responses. We further revealed that G-matrices also evolved in the selection processes.</p><p><strong>Conclusions: </strong>Overall, our integrative study shows that floral signals, especially volatiles, evolve under selection in a mostly predictable way, at least during short term evolution. Evolutionary constraints stemming from genetic covariance affected traits evolutionary trajectories and thus it is important to include genetic covariance for predicting the evolutionary changes of a comprehensive suite of traits. Other processes such as resource limitation and selfing also need to be considered for a better understanding of floral trait evolution.</p>","PeriodicalId":9111,"journal":{"name":"BMC Evolutionary Biology","volume":"20 1","pages":"127"},"PeriodicalIF":3.4,"publicationDate":"2020-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7517814/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38418689","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 : 2020-09-22DOI: 10.1186/s12862-020-01691-8
Didem P Sarikaya, Julie Cridland, Adam Tarakji, Hayley Sheehy, Sophia Davis, Ashley Kochummen, Ryan Hatmaker, Nossin Khan, Joanna Chiu, David J Begun
Background: One hypothesis for the function of sleep is that it serves as a mechanism to conserve energy. Recent studies have suggested that increased sleep can be an adaptive mechanism to improve survival under food deprivation in Drosophila melanogaster. To test the generality of this hypothesis, we compared sleep and its plastic response to starvation in a temperate and tropical population of Drosophila melanogaster.
Results: We found that flies from the temperate population were more starvation resistant, and hypothesized that they would engage in behaviors that are considered to conserve energy, including increased sleep and reduced movement. Surprisingly, temperate flies slept less and moved more when they were awake compared to tropical flies, both under fed and starved conditions, therefore sleep did not correlate with population-level differences in starvation resistance. In contrast, total sleep and percent change in sleep when starved were strongly positively correlated with starvation resistance within the tropical population, but not within the temperate population. Thus, we observe unexpectedly complex relationships between starvation and sleep that vary both within and across populations. These observations falsify the simple hypothesis of a straightforward relationship between sleep and energy conservation. We also tested the hypothesis that starvation is correlated with metabolic phenotypes by investigating stored lipid and carbohydrate levels, and found that stored metabolites partially contributed towards variation starvation resistance.
Conclusions: Our findings demonstrate that the function of sleep under starvation can rapidly evolve on short timescales and raise new questions about the physiological correlates of sleep and the extent to which variation in sleep is shaped by natural selection.
{"title":"Phenotypic coupling of sleep and starvation resistance evolves in D. melanogaster.","authors":"Didem P Sarikaya, Julie Cridland, Adam Tarakji, Hayley Sheehy, Sophia Davis, Ashley Kochummen, Ryan Hatmaker, Nossin Khan, Joanna Chiu, David J Begun","doi":"10.1186/s12862-020-01691-8","DOIUrl":"10.1186/s12862-020-01691-8","url":null,"abstract":"<p><strong>Background: </strong>One hypothesis for the function of sleep is that it serves as a mechanism to conserve energy. Recent studies have suggested that increased sleep can be an adaptive mechanism to improve survival under food deprivation in Drosophila melanogaster. To test the generality of this hypothesis, we compared sleep and its plastic response to starvation in a temperate and tropical population of Drosophila melanogaster.</p><p><strong>Results: </strong>We found that flies from the temperate population were more starvation resistant, and hypothesized that they would engage in behaviors that are considered to conserve energy, including increased sleep and reduced movement. Surprisingly, temperate flies slept less and moved more when they were awake compared to tropical flies, both under fed and starved conditions, therefore sleep did not correlate with population-level differences in starvation resistance. In contrast, total sleep and percent change in sleep when starved were strongly positively correlated with starvation resistance within the tropical population, but not within the temperate population. Thus, we observe unexpectedly complex relationships between starvation and sleep that vary both within and across populations. These observations falsify the simple hypothesis of a straightforward relationship between sleep and energy conservation. We also tested the hypothesis that starvation is correlated with metabolic phenotypes by investigating stored lipid and carbohydrate levels, and found that stored metabolites partially contributed towards variation starvation resistance.</p><p><strong>Conclusions: </strong>Our findings demonstrate that the function of sleep under starvation can rapidly evolve on short timescales and raise new questions about the physiological correlates of sleep and the extent to which variation in sleep is shaped by natural selection.</p>","PeriodicalId":9111,"journal":{"name":"BMC Evolutionary Biology","volume":"20 1","pages":"126"},"PeriodicalIF":3.4,"publicationDate":"2020-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7507639/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38410514","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 : 2020-09-21DOI: 10.1186/s12862-020-01683-8
Dong Liu, Yuanyuan Zhang, Ming Zhang, Jinquan Yang, Wenqiao Tang
Background: The family Labridae made up of 519 species in the world. The functional evolution of the feeding-related jaws leaded to differentiation of species, and the pharyngeal jaw apparatus evolved independently, but evolutionary mechanism still remain unaddressed in wrasses. Mitogenomes data can be used to infer genetic diversification and investigate evolutionary history of wrasses, whereas only eight complete mitogenomes in this family have been sequenced to date. Here, we sequenced the complete mitogenomes of Iniistius trivittatus to investigate genetic differentiation among wrasse species.
Results: We sequenced the complete mitogenomes of I. trivittatus using a novel PCR strategy. The I. trivittatus mitogenomes is 16,820 bp in length and includes 13 protein -coding genes, 2 ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes, and a control region. Compared to eight known mitochondrial genome, 2 additional noncoding regions (lengths of 121 and 107 bp), or so-called inserts, are found in the intergenic regions 12S rRNA - tRNAVal - 16S rRNA. The presumed origin of the two rare inserts is from tRNA- related retrotransposons. Compared with cytochrome b gene, the two insert sequences are highly conserved at the intraspecies level, but they showed significant variation and low similarity (< 70%) at the interspecies level. The insert events were only observed in I. trivittatus by checking the phylogenetic trees based on the complete mitogenomes of Labrida species. This finding provides evidence that in the mitogenomes, retrotransposon inserts result in intraspecific homoplasmy and interspecific heteroplasmy by natural selection and adaptation to various environments.
Conclusions: This study found additional mitogenome inserts limited in wrasse species. The rRNA genes with inserts might have experienced a selective pressure for adaptation to feeding modes. Such knowledge can enable a better understanding of molecular mechanism underlying morphological evolution in wrasses.
{"title":"Complete mitochondrial genome of Iniistius trivittatus and unique variation in two observed inserts between rRNA and tRNA genes in wrasses.","authors":"Dong Liu, Yuanyuan Zhang, Ming Zhang, Jinquan Yang, Wenqiao Tang","doi":"10.1186/s12862-020-01683-8","DOIUrl":"10.1186/s12862-020-01683-8","url":null,"abstract":"<p><strong>Background: </strong>The family Labridae made up of 519 species in the world. The functional evolution of the feeding-related jaws leaded to differentiation of species, and the pharyngeal jaw apparatus evolved independently, but evolutionary mechanism still remain unaddressed in wrasses. Mitogenomes data can be used to infer genetic diversification and investigate evolutionary history of wrasses, whereas only eight complete mitogenomes in this family have been sequenced to date. Here, we sequenced the complete mitogenomes of Iniistius trivittatus to investigate genetic differentiation among wrasse species.</p><p><strong>Results: </strong>We sequenced the complete mitogenomes of I. trivittatus using a novel PCR strategy. The I. trivittatus mitogenomes is 16,820 bp in length and includes 13 protein -coding genes, 2 ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes, and a control region. Compared to eight known mitochondrial genome, 2 additional noncoding regions (lengths of 121 and 107 bp), or so-called inserts, are found in the intergenic regions 12S rRNA - tRNA<sup>Val</sup> - 16S rRNA. The presumed origin of the two rare inserts is from tRNA- related retrotransposons. Compared with cytochrome b gene, the two insert sequences are highly conserved at the intraspecies level, but they showed significant variation and low similarity (< 70%) at the interspecies level. The insert events were only observed in I. trivittatus by checking the phylogenetic trees based on the complete mitogenomes of Labrida species. This finding provides evidence that in the mitogenomes, retrotransposon inserts result in intraspecific homoplasmy and interspecific heteroplasmy by natural selection and adaptation to various environments.</p><p><strong>Conclusions: </strong>This study found additional mitogenome inserts limited in wrasse species. The rRNA genes with inserts might have experienced a selective pressure for adaptation to feeding modes. Such knowledge can enable a better understanding of molecular mechanism underlying morphological evolution in wrasses.</p>","PeriodicalId":9111,"journal":{"name":"BMC Evolutionary Biology","volume":"20 1","pages":"125"},"PeriodicalIF":3.4,"publicationDate":"2020-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7507615/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38403229","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 : 2020-09-21DOI: 10.1186/s12862-020-01682-9
Deborah Wall-Palmer, Arie W Janssen, Erica Goetze, Le Qin Choo, Lisette Mekkes, Katja T C A Peijnenburg
Background: The aragonite shelled, planktonic gastropod family Atlantidae (shelled heteropods) is likely to be one of the first groups to be impacted by imminent ocean changes, including ocean warming and ocean acidification. With a fossil record spanning at least 100 Ma, atlantids have experienced and survived global-scale ocean changes and extinction events in the past. However, the diversification patterns and tempo of evolution in this family are largely unknown.
Results: Based on a concatenated maximum likelihood phylogeny of three genes (cytochrome c oxidase subunit 1 mitochondrial DNA, 28S and 18S ribosomal rRNA) we show that the three extant genera of the family Atlantidae, Atlanta, Protatlanta and Oxygyrus, form monophyletic groups. The genus Atlanta is split into two groups, one exhibiting smaller, well ornamented shells, and the other having larger, less ornamented shells. The fossil record, in combination with a fossil-calibrated phylogeny, suggests that large scale atlantid extinction was accompanied by considerable and rapid diversification over the last 25 Ma, potentially driven by vicariance events.
Conclusions: Now confronted with a rapidly changing modern ocean, the ability of atlantids to survive past global change crises gives some optimism that they may be able to persist through the Anthropocene.
背景:有文石壳的浮游腹足类亚特兰特科(有壳异足类)很可能是最先受到迫在眉睫的海洋变化(包括海洋变暖和海洋酸化)影响的类群之一。亚特兰蒂斯科的化石记录至少跨越了 100 个万年前,它们在过去经历了全球规模的海洋变化和物种灭绝事件,并幸存了下来。然而,该科动物的多样化模式和进化速度在很大程度上还不为人所知:结果:基于三个基因(细胞色素 c 氧化酶亚单位 1 线粒体 DNA、28S 和 18S 核糖体 rRNA)的最大似然法系统发生分析表明,亚特兰特科现存的三个属:亚特兰特属(Atlanta)、原亚特兰特属(Protatlanta)和 Oxygyrus 属(Oxygyrus)形成了单系群。亚特兰大属分为两组,一组的贝壳较小、装饰精美,另一组的贝壳较大、装饰较少。化石记录与经化石校准的系统发育相结合,表明在过去的 25 Ma 期间,伴随着大规模的亚特兰蒂斯类灭绝的是相当大的快速多样化,这可能是由沧海桑田事件驱动的:现在,面对瞬息万变的现代海洋,蝠鲼能够在过去的全球变化危机中幸存下来,这让人乐观地认为,它们或许能够在人类世继续生存下去。
{"title":"Fossil-calibrated molecular phylogeny of atlantid heteropods (Gastropoda, Pterotracheoidea).","authors":"Deborah Wall-Palmer, Arie W Janssen, Erica Goetze, Le Qin Choo, Lisette Mekkes, Katja T C A Peijnenburg","doi":"10.1186/s12862-020-01682-9","DOIUrl":"10.1186/s12862-020-01682-9","url":null,"abstract":"<p><strong>Background: </strong>The aragonite shelled, planktonic gastropod family Atlantidae (shelled heteropods) is likely to be one of the first groups to be impacted by imminent ocean changes, including ocean warming and ocean acidification. With a fossil record spanning at least 100 Ma, atlantids have experienced and survived global-scale ocean changes and extinction events in the past. However, the diversification patterns and tempo of evolution in this family are largely unknown.</p><p><strong>Results: </strong>Based on a concatenated maximum likelihood phylogeny of three genes (cytochrome c oxidase subunit 1 mitochondrial DNA, 28S and 18S ribosomal rRNA) we show that the three extant genera of the family Atlantidae, Atlanta, Protatlanta and Oxygyrus, form monophyletic groups. The genus Atlanta is split into two groups, one exhibiting smaller, well ornamented shells, and the other having larger, less ornamented shells. The fossil record, in combination with a fossil-calibrated phylogeny, suggests that large scale atlantid extinction was accompanied by considerable and rapid diversification over the last 25 Ma, potentially driven by vicariance events.</p><p><strong>Conclusions: </strong>Now confronted with a rapidly changing modern ocean, the ability of atlantids to survive past global change crises gives some optimism that they may be able to persist through the Anthropocene.</p>","PeriodicalId":9111,"journal":{"name":"BMC Evolutionary Biology","volume":"20 1","pages":"124"},"PeriodicalIF":3.4,"publicationDate":"2020-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7507655/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38403226","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 : 2020-09-17DOI: 10.1186/s12862-020-01689-2
Britta Bueker, Marco Alexandre Guerreiro, Michael E Hood, Andreas Brachmann, Sven Rahmann, Dominik Begerow
Background: Hybridization is a central mechanism in evolution, producing new species or introducing important genetic variation into existing species. In plant-pathogenic fungi, adaptation and specialization to exploit a host species are key determinants of evolutionary success. Here, we performed experimental crosses between the two pathogenic Microbotryum species, M. lychnidis-dioicae and M. silenes-acaulis that are specialized to different hosts. The resulting offspring were analyzed on phenotypic and genomic levels to describe genomic characteristics of hybrid offspring and genetic factors likely involved in host-specialization.
Results: Genomic analyses of interspecific fungal hybrids revealed that individuals were most viable if the majority of loci were inherited from one species. Interestingly, species-specific loci were strictly controlled by the species' origin of the mating type locus. Moreover we detected signs of crossing over and chromosome duplications in the genomes of the analyzed hybrids. In Microbotryum, mitochondrial DNA was found to be uniparentally inherited from the a2 mating type. Genome comparison revealed that most gene families are shared and the majority of genes are conserved between the two species, indicating very similar biological features, including infection and pathogenicity processes. Moreover, we detected 211 candidate genes that were retained under host-driven selection of backcrossed lines. These genes and might therefore either play a crucial role in host specialization or be linked to genes that are essential for specialization.
Conclusion: The combination of genome analyses with experimental selection and hybridization is a promising way to investigate host-pathogen interactions. This study manifests genetic factors of host specialization that are required for successful biotrophic infection of the post-zygotic stage, but also demonstrates the strong influence of intra-genomic conflicts or instabilities on the viability of hybrids in the haploid host-independent stage.
背景:杂交是生物进化的核心机制,可产生新物种或为现有物种引入重要的遗传变异。在植物病原真菌中,利用宿主物种的适应性和专一性是决定进化成功与否的关键因素。在这里,我们进行了两种致病性微囊菌(M. lychnidis-dioicae和M. silenes-acaulis)之间的杂交实验,这两种致病性微囊菌专门利用不同的寄主。对杂交后代的表型和基因组水平进行了分析,以描述杂交后代的基因组特征以及可能参与寄主专化的遗传因素:结果:对种间真菌杂交种的基因组分析表明,如果大多数基因位点都遗传自一个物种,那么个体的生存能力最强。有趣的是,物种特异性基因座受到交配型基因座的物种起源的严格控制。此外,我们还在分析的杂交种基因组中发现了杂交和染色体重复的迹象。在微囊藻中,我们发现线粒体 DNA 是由 a2 交配型单亲遗传的。基因组比较显示,两个物种之间共享大多数基因家族,而且大多数基因是保守的,这表明两个物种的生物学特征非常相似,包括感染和致病过程。此外,我们还发现了 211 个候选基因,这些基因在宿主驱动的回交系选择中被保留下来。因此,这些基因可能在宿主特化过程中发挥了关键作用,或者与特化所必需的基因有关:结论:将基因组分析与实验选择和杂交结合起来,是研究宿主与病原体相互作用的一种很有前途的方法。这项研究表明,宿主特化的遗传因素是后合子阶段成功的生物营养感染所必需的,同时也证明了基因组内的冲突或不稳定对单倍体宿主独立阶段杂交种的生存能力有很大影响。
{"title":"Meiotic recombination in the offspring of Microbotryum hybrids and its impact on pathogenicity.","authors":"Britta Bueker, Marco Alexandre Guerreiro, Michael E Hood, Andreas Brachmann, Sven Rahmann, Dominik Begerow","doi":"10.1186/s12862-020-01689-2","DOIUrl":"10.1186/s12862-020-01689-2","url":null,"abstract":"<p><strong>Background: </strong>Hybridization is a central mechanism in evolution, producing new species or introducing important genetic variation into existing species. In plant-pathogenic fungi, adaptation and specialization to exploit a host species are key determinants of evolutionary success. Here, we performed experimental crosses between the two pathogenic Microbotryum species, M. lychnidis-dioicae and M. silenes-acaulis that are specialized to different hosts. The resulting offspring were analyzed on phenotypic and genomic levels to describe genomic characteristics of hybrid offspring and genetic factors likely involved in host-specialization.</p><p><strong>Results: </strong>Genomic analyses of interspecific fungal hybrids revealed that individuals were most viable if the majority of loci were inherited from one species. Interestingly, species-specific loci were strictly controlled by the species' origin of the mating type locus. Moreover we detected signs of crossing over and chromosome duplications in the genomes of the analyzed hybrids. In Microbotryum, mitochondrial DNA was found to be uniparentally inherited from the a<sub>2</sub> mating type. Genome comparison revealed that most gene families are shared and the majority of genes are conserved between the two species, indicating very similar biological features, including infection and pathogenicity processes. Moreover, we detected 211 candidate genes that were retained under host-driven selection of backcrossed lines. These genes and might therefore either play a crucial role in host specialization or be linked to genes that are essential for specialization.</p><p><strong>Conclusion: </strong>The combination of genome analyses with experimental selection and hybridization is a promising way to investigate host-pathogen interactions. This study manifests genetic factors of host specialization that are required for successful biotrophic infection of the post-zygotic stage, but also demonstrates the strong influence of intra-genomic conflicts or instabilities on the viability of hybrids in the haploid host-independent stage.</p>","PeriodicalId":9111,"journal":{"name":"BMC Evolutionary Biology","volume":"20 1","pages":"123"},"PeriodicalIF":3.4,"publicationDate":"2020-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7499883/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38490808","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 : 2020-09-16DOI: 10.1186/s12862-020-01690-9
David Tarkhnishvili, Alexey Yanchukov, Mehmet Kürşat Şahin, Mariam Gabelaia, Marine Murtskhvaladze, Kamil Candan, Eduard Galoyan, Marine Arakelyan, Giorgi Iankoshvili, Yusuf Kumlutaş, Çetin Ilgaz, Ferhat Matur, Faruk Çolak, Meriç Erdolu, Sofiko Kurdadze, Natia Barateli, Cort L Anderson
Background: The majority of parthenogenetic vertebrates derive from hybridization between sexually reproducing species, but the exact number of hybridization events ancestral to currently extant clonal lineages is difficult to determine. Usually, we do not know whether the parental species are able to contribute their genes to the parthenogenetic vertebrate lineages after the initial hybridization. In this paper, we address the hypothesis, whether some genotypes of seven phenotypically distinct parthenogenetic rock lizards (genus Darevskia) could have resulted from back-crosses of parthenogens with their presumed parental species. We also tried to identify, as precise as possible, the ancestral populations of all seven parthenogens.
Results: We analysed partial mtDNA sequences and microsatellite genotypes of all seven parthenogens and their presumed ansectral species, sampled across the entire geographic range of parthenogenesis in this group. Our results confirm the previous designation of the parental species, but further specify the maternal populations that are likely ancestral to different parthenogenetic lineages. Contrary to the expectation of independent hybrid origins of the unisexual taxa, we found that genotypes at multiple loci were shared frequently between different parthenogenetic species. The highest proportions of shared genotypes were detected between (i) D. sapphirina and D. bendimahiensis and (ii) D. dahli and D. armeniaca, and less often between other parthenogens. In case (ii), genotypes at the remaining loci were notably distinct.
Conclusions: We suggest that both observations (i-ii) can be explained by two parthenogenetic forms tracing their origin to a single initial hybridization event. In case (ii), however, occasional gene exchange between the unisexual and the parental bisexual species could have taken place after the onset of parthenogenetic reproduction. Indeed, backcrossed polyploid hybrids are relatively frequent in Darevskia, although no direct evidence of recent gene flow has been previously documented. Our results further suggest that parthenogens are losing heterozygosity as a result of allelic conversion, hence their fitness is expected to decline over time as genetic diversity declines. Backcrosses with the parental species could be a rescue mechanism which might prevent this decline, and therefore increase the persistance of unisexual forms.
{"title":"Genotypic similarities among the parthenogenetic Darevskia rock lizards with different hybrid origins.","authors":"David Tarkhnishvili, Alexey Yanchukov, Mehmet Kürşat Şahin, Mariam Gabelaia, Marine Murtskhvaladze, Kamil Candan, Eduard Galoyan, Marine Arakelyan, Giorgi Iankoshvili, Yusuf Kumlutaş, Çetin Ilgaz, Ferhat Matur, Faruk Çolak, Meriç Erdolu, Sofiko Kurdadze, Natia Barateli, Cort L Anderson","doi":"10.1186/s12862-020-01690-9","DOIUrl":"https://doi.org/10.1186/s12862-020-01690-9","url":null,"abstract":"<p><strong>Background: </strong>The majority of parthenogenetic vertebrates derive from hybridization between sexually reproducing species, but the exact number of hybridization events ancestral to currently extant clonal lineages is difficult to determine. Usually, we do not know whether the parental species are able to contribute their genes to the parthenogenetic vertebrate lineages after the initial hybridization. In this paper, we address the hypothesis, whether some genotypes of seven phenotypically distinct parthenogenetic rock lizards (genus Darevskia) could have resulted from back-crosses of parthenogens with their presumed parental species. We also tried to identify, as precise as possible, the ancestral populations of all seven parthenogens.</p><p><strong>Results: </strong>We analysed partial mtDNA sequences and microsatellite genotypes of all seven parthenogens and their presumed ansectral species, sampled across the entire geographic range of parthenogenesis in this group. Our results confirm the previous designation of the parental species, but further specify the maternal populations that are likely ancestral to different parthenogenetic lineages. Contrary to the expectation of independent hybrid origins of the unisexual taxa, we found that genotypes at multiple loci were shared frequently between different parthenogenetic species. The highest proportions of shared genotypes were detected between (i) D. sapphirina and D. bendimahiensis and (ii) D. dahli and D. armeniaca, and less often between other parthenogens. In case (ii), genotypes at the remaining loci were notably distinct.</p><p><strong>Conclusions: </strong>We suggest that both observations (i-ii) can be explained by two parthenogenetic forms tracing their origin to a single initial hybridization event. In case (ii), however, occasional gene exchange between the unisexual and the parental bisexual species could have taken place after the onset of parthenogenetic reproduction. Indeed, backcrossed polyploid hybrids are relatively frequent in Darevskia, although no direct evidence of recent gene flow has been previously documented. Our results further suggest that parthenogens are losing heterozygosity as a result of allelic conversion, hence their fitness is expected to decline over time as genetic diversity declines. Backcrosses with the parental species could be a rescue mechanism which might prevent this decline, and therefore increase the persistance of unisexual forms.</p>","PeriodicalId":9111,"journal":{"name":"BMC Evolutionary Biology","volume":"20 1","pages":"122"},"PeriodicalIF":3.4,"publicationDate":"2020-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s12862-020-01690-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38484380","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 : 2020-09-16DOI: 10.1186/s12862-020-01679-4
Erica S Nielsen, Romina Henriques, Maria Beger, Robert J Toonen, Sophie von der Heyden
Background: As global change and anthropogenic pressures continue to increase, conservation and management increasingly needs to consider species' potential to adapt to novel environmental conditions. Therefore, it is imperative to characterise the main selective forces acting on ecosystems, and how these may influence the evolutionary potential of populations and species. Using a multi-model seascape genomics approach, we compare putative environmental drivers of selection in three sympatric southern African marine invertebrates with contrasting ecology and life histories: Cape urchin (Parechinus angulosus), Common shore crab (Cyclograpsus punctatus), and Granular limpet (Scutellastra granularis).
Results: Using pooled (Pool-seq), restriction-site associated DNA sequencing (RAD-seq), and seven outlier detection methods, we characterise genomic variation between populations along a strong biogeographical gradient. Of the three species, only S. granularis showed significant isolation-by-distance, and isolation-by-environment driven by sea surface temperatures (SST). In contrast, sea surface salinity (SSS) and range in air temperature correlated more strongly with genomic variation in C. punctatus and P. angulosus. Differences were also found in genomic structuring between the three species, with outlier loci contributing to two clusters in the East and West Coasts for S. granularis and P. angulosus, but not for C. punctatus.
Conclusion: The findings illustrate distinct evolutionary potential across species, suggesting that species-specific habitat requirements and responses to environmental stresses may be better predictors of evolutionary patterns than the strong environmental gradients within the region. We also found large discrepancies between outlier detection methodologies, and thus offer a novel multi-model approach to identifying the principal environmental selection forces acting on species. Overall, this work highlights how adding a comparative approach to seascape genomics (both with multiple models and species) can elucidate the intricate evolutionary responses of ecosystems to global change.
{"title":"Multi-model seascape genomics identifies distinct environmental drivers of selection among sympatric marine species.","authors":"Erica S Nielsen, Romina Henriques, Maria Beger, Robert J Toonen, Sophie von der Heyden","doi":"10.1186/s12862-020-01679-4","DOIUrl":"https://doi.org/10.1186/s12862-020-01679-4","url":null,"abstract":"<p><strong>Background: </strong>As global change and anthropogenic pressures continue to increase, conservation and management increasingly needs to consider species' potential to adapt to novel environmental conditions. Therefore, it is imperative to characterise the main selective forces acting on ecosystems, and how these may influence the evolutionary potential of populations and species. Using a multi-model seascape genomics approach, we compare putative environmental drivers of selection in three sympatric southern African marine invertebrates with contrasting ecology and life histories: Cape urchin (Parechinus angulosus), Common shore crab (Cyclograpsus punctatus), and Granular limpet (Scutellastra granularis).</p><p><strong>Results: </strong>Using pooled (Pool-seq), restriction-site associated DNA sequencing (RAD-seq), and seven outlier detection methods, we characterise genomic variation between populations along a strong biogeographical gradient. Of the three species, only S. granularis showed significant isolation-by-distance, and isolation-by-environment driven by sea surface temperatures (SST). In contrast, sea surface salinity (SSS) and range in air temperature correlated more strongly with genomic variation in C. punctatus and P. angulosus. Differences were also found in genomic structuring between the three species, with outlier loci contributing to two clusters in the East and West Coasts for S. granularis and P. angulosus, but not for C. punctatus.</p><p><strong>Conclusion: </strong>The findings illustrate distinct evolutionary potential across species, suggesting that species-specific habitat requirements and responses to environmental stresses may be better predictors of evolutionary patterns than the strong environmental gradients within the region. We also found large discrepancies between outlier detection methodologies, and thus offer a novel multi-model approach to identifying the principal environmental selection forces acting on species. Overall, this work highlights how adding a comparative approach to seascape genomics (both with multiple models and species) can elucidate the intricate evolutionary responses of ecosystems to global change.</p>","PeriodicalId":9111,"journal":{"name":"BMC Evolutionary Biology","volume":"20 1","pages":"121"},"PeriodicalIF":3.4,"publicationDate":"2020-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/s12862-020-01679-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38389370","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 : 2020-09-15DOI: 10.1186/s12862-020-01666-9
Megan Phifer-Rixey, Bettina Harr, Jody Hey
Background: The three main subspecies of house mice, Mus musculus castaneus, Mus musculus domesticus, and Mus musculus musculus, are estimated to have diverged ~ 350-500KYA. Resolution of the details of their evolutionary history is complicated by their relatively recent divergence, ongoing gene flow among the subspecies, and complex demographic histories. Previous studies have been limited to some extent by the number of loci surveyed and/or by the scope of the method used. Here, we apply a method (IMa3) that provides an estimate of a population phylogeny while allowing for complex histories of gene exchange.
Results: Results strongly support a topology with M. m. domesticus as sister to M. m. castaneus and M. m. musculus. In addition, we find evidence of gene flow between all pairs of subspecies, but that gene flow is most restricted from M. m. musculus into M. m. domesticus. Estimates of other key parameters are dependent on assumptions regarding generation time and mutation rate in house mice. Nevertheless, our results support previous findings that the effective population size, Ne, of M. m. castaneus is larger than that of the other two subspecies, that the three subspecies began diverging ~ 130 - 420KYA, and that the time between divergence events was short.
Conclusions: Joint demographic and phylogenetic analyses of genomic data provide a clearer picture of the history of divergence in house mice.
{"title":"Further resolution of the house mouse (Mus musculus) phylogeny by integration over isolation-with-migration histories.","authors":"Megan Phifer-Rixey, Bettina Harr, Jody Hey","doi":"10.1186/s12862-020-01666-9","DOIUrl":"10.1186/s12862-020-01666-9","url":null,"abstract":"<p><strong>Background: </strong>The three main subspecies of house mice, Mus musculus castaneus, Mus musculus domesticus, and Mus musculus musculus, are estimated to have diverged ~ 350-500KYA. Resolution of the details of their evolutionary history is complicated by their relatively recent divergence, ongoing gene flow among the subspecies, and complex demographic histories. Previous studies have been limited to some extent by the number of loci surveyed and/or by the scope of the method used. Here, we apply a method (IMa3) that provides an estimate of a population phylogeny while allowing for complex histories of gene exchange.</p><p><strong>Results: </strong>Results strongly support a topology with M. m. domesticus as sister to M. m. castaneus and M. m. musculus. In addition, we find evidence of gene flow between all pairs of subspecies, but that gene flow is most restricted from M. m. musculus into M. m. domesticus. Estimates of other key parameters are dependent on assumptions regarding generation time and mutation rate in house mice. Nevertheless, our results support previous findings that the effective population size, N<sub>e,</sub> of M. m. castaneus is larger than that of the other two subspecies, that the three subspecies began diverging ~ 130 - 420KYA, and that the time between divergence events was short.</p><p><strong>Conclusions: </strong>Joint demographic and phylogenetic analyses of genomic data provide a clearer picture of the history of divergence in house mice.</p>","PeriodicalId":9111,"journal":{"name":"BMC Evolutionary Biology","volume":"20 1","pages":"120"},"PeriodicalIF":3.4,"publicationDate":"2020-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7493149/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"38480469","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}