Journal of Genetics最新文献

Eukaryotic proteomes harbour tandem repeats (TRs) of amino acids that may play critical roles in the biology of organisms. While a few TRs have been shown to contribute to protein structure and function, information about the vast majority of repeat regions remains obscure. This article reports a detailed computational analysis of the repeat content of different Plasmodium species proteomes, identifying P. falciparum (Pf) and P. vivax to be exceptionally rich in TR regions. P. falciparum 'repetome' was found to carry longer TRs, which were majorly present in exported parasite proteins, important for pathogen survival and immune evasion. Short and intermediate TRs of P. falciparum showed a bias towards Asparagine usage, suggesting an evolutionary outcome influenced by replication slippage and positive selection. Gene ontology analysis revealed the largest proportion of TR containing Pf proteins to be involved in binding nucleic acids, proteins and other small molecules. Surprisingly, the Plasmodium specific variable surface antigen (VSA) families known to have roles in immune evasion and cytoadherence were found to contain low repeat content. Our analysis also revealed that all the TR containing VSAs were sero-reactive, where several antigenic peptides were present within the repeats. Three-dimensional structure predictions of TR regions showed several repeats to form ordered super-secondary conformations, which are often reported to facilitate intermolecular interactions. Overall, this comprehensive study provides glimpses into the probable roles of TRs in Plasmodium biology and also suggests a novel method for understanding protein function via characterization of repetitive sequences.

Dps and MSUD: Twenty-five years ago, Robert Metzenberg and colleagues discovered why a cross between a normal euploid Neurospora crassa strain and one carrying any chromosome segment duplication (N X Dp) was barren and produced only a few exceptional progeny ascospores. The culprit was a novel gene-silencing process, which they named meiotic silencing by unpaired DNA (MSUD; Cell 107, 905-916, 2001).

Hippophae rhamnoides ssp. turkestanica, a subdioecious plant inhabiting the cold desert of the Indian Himalaya, has gained immense recognition for its nutritional and medicinal values. In recent years, the plant species has proven to be a suitable system to understand the evolution of dioecy. Despite its biological significance, the cytogenetics of this dioecious plant is unclear due to various conflicting accounts of its X-Y chromosome system, particularly the length of Y-chromosome. In this study, we resolved these ambiguities through comprehensive cytogenetic analyses across diverse western Himalayan populations. Using morphometric analysis and fluorescence in situ hybridization (FISH) with a gender-specific marker (HRMSSR), we confirmed homomorphic XX chromosomes in females and heteromorphic sex-chromosomes in males with a notably smaller Y-chromosome. The investigation also revealed a predominant somatic chromosome number of 2n = 24, although minor deviations (2n = 18, 20, 22) appeared at the seed level. These findings highlight an evolutionarily advanced sex-chromosome system. This first detailed cytogenetic investigation of Himalayan Seabuckthorn provides critical insights into the chromosomal architecture, laying a crucial foundation for future evolutionary, genomic, and conservation studies in the species.

Plant height and spikelet density are two important traits for wheat (Triticum aestivum L.) yield. The development of wheat mutants not only provides new genetic resources for wheat improvement but also facilitates our understanding of the molecular regulation of these traits. Previously, we obtained a mutant named dwarf and spike compactness (dsc) from wheat cultivar Guomai301 (wild type, WT) treated with ethyl methane sulphonate. This study investigates the heredity, mutated gene location, and the candidate gene of dsc. Highresolution chromosome painting analysis indicated that there were no visible structural variations in the mutant dsc. Genetic analysis indicated that the phenotype of dsc was controlled by a single dominant gene, named as dsc. The wheat 660 K single-nucleotide polymorphism (SNP) array and simple sequence repeat (SSR) marker assay were employed to map the mutated gene. A total of 984 SNPs were identified between the DNA bulks, among which, 492 SNPs were located on chromosome 5A in 580-680 Mb genomic region, which occupied 50% of the total SNPs. The gene dsc was mapped in a 33.4 Mb (625.7-659.1 Mb) region on chromosome arm 5AL, flanked by SSR markers Xbarc319 and Xgpw2136, where 5AQ is located. Sequences and expression patterns of 5AQ from WTand dsc were compared. The two 5AQs had a SNP (G>A) in the miR172 binding site. A dCAPS marker was developed based on the SNP, and the marker was cosegregated with the mutated phenotypes in a F_2:3 population derived from the cross dsc x Chinese Spring (CS). This result demonstrated that the gene 5AQ was the mutated gene of dsc. The expression levels of 5AQ were significantly higher in roots, stems, leaves and spikes of mutant dsc than those in WT. Our results demonstrated that point mutation in the miR172 binding site of the 5AQ likely increased its transcript level via a reduction in miRNA-dependent degradation, and this resulted in pleiotropic effects on spikelet density and plant height. Obviously, miR172-Q was a key regulation module for wheat growth and spike development. The dCAPS marker could be used to detect the elite allele of Q in wheat breeding. Regulation of miR172-Q module might be an approach for wheat yield breeding.

Heterotrimeric G-proteins are multifunctional modulators that participate in a wide range of growth and developmental processes in eukaryotic species, including yeast, plants, and animals. In this study, we characterized a maize mutant, ct2, that showed a compact architecture and reproductive-organ-related phenotypic variation. Heredity analysis indicated that the mutant phenotypes resulted from monogenic inheritance. The target gene, CT2, was cloned using bulked segregant analysis and map-based cloning. Sequence alignment showed that the ct2 mutation was the result of a 185-bp sequence insertion at the 3' terminal of CT2. Protein structure prediction and phylogenetic analysis indicated that CT2 is a canonical Gɑ of monocotyledonous plants. Through phenotypic identification, we found that CT2 was involved in yield-related traits in maize. Furthermore, our findings indicated that CT2 promotes cell proliferation in stem internodes, which may result from the upregulation of zeatin biosynthesis by CT2. This research provides direction for further studies in the biological function of CT2 in cell proliferation and in yield-related traits, which will be beneficial for maize breeding through screening and application of beneficial alleles.

Primary microcephaly (MCPH) is an autosomal recessive condition of reduced head circumference due to a small cerebral cortex. Genetic studies have reported 30 MCPH genes. The aim of this study was to investigate whether the genetic mapping of the MCPH gene mutation is involved in primary microcephaly. For genetic mapping, whole exome and Sanger sequencing were performed. In this study, we identified a homozygous missense mutation, NM_001259.8:c.589G[A, p.(Ala197Thr) of CDK6 in a consanguineous MCPH family. Since the identification of CDK6 as a candidate gene for MCPH, this is the first report of an additional family mapping to the MCPH12locus. Molecular-genetic analysis of both families revealed an overlapping homozygous region harbouring the causal mutation in CDK6 and a common haplotype, which led to a significant reduction of the critical MCPH12 locus. Our results suggest a founder effect of c.589G[A, p.(Ala197Thr) in the Pakistani population.

The stems of Zizania latifolia, an important vegetable in China, are targeted by the pathogen Ustilago esculenta, triggering a response through the mitogen-activated protein kinase (MAPK) signalling pathway. To investigate the characteristics and the role of MAPK gene family in the biological stress response, a bioinformatics-based analysis was performed, and the expression patterns of ZlMPKs and MAPK-infection pathway-related genes were detected in male plants inoculated with U. esculenta. Twenty-five ZlMPK genes were identified and divided into four subgroups A, B, C and D: carried a conserved TEY motif, while D had a conserved TDY motif. The ZlMPKs were located in the nucleus, cytoplasm, chloroplast, mitochondria, and peroxisome, and most exhibited evidence of gene duplication events. The relative expression of most ZlMPKs was the highest at 3 h after inoculation with U. esculenta, with 21 ZlMPKs being upregulated and four being downregulated. Additionally, nine of 11 MAPK-infection pathway-related genes were upregulated at 3 h after inoculation. ZlMPK3 was cloned and transformed into Arabidopsis thaliana, and two overexpression lines were identified by resistance screening and molecular detection. Their responses to Botrytis cinerea infection were studied. The leaf inoculation sites of ZlMPK3-overexpression plants revealed damage, while those of wild-type plants did not. The relative expression of MAPK pathogen related genes was altered after inoculation. Specifically, the expression levels of the ethylene biosynthetic pathway gene AtACS6 and five cysteine-rich secretory protein CAP genes were significantly upregulated, while those of systemic acquired resistance marker gene, pathogenesis-related 1 AtPR1 and early defense signalling gene AtFRK1 were significantly downregulated, indicating that resistance to B. cinerea was weakened in the ZlMPK3-overexpression lines.

The ornamental fish Amatitlania nigrofasciata, known as the convict or zebra cichlid, is a small Central American tropical freshwater fish that also serves as a model for behavioural studies. Its phylogenetic relationship with other cichlids in the tribe Heroini remains unclear. Here, we sequenced the mitogenome of A. nigrofasciata. The mitogenome spans 16,529 bp and includes the standard complement of 13 protein-coding genes (PCGs), 22 transfer RNA genes, two ribosomal RNA genes, and one D-loop region, with the same order and strand distribution as those of other cichlids. Phylogenetic analysis of the 13 PCGs showed that A. nigrofasciata is more closely related to Amphilophus, in a clade including Parachromis, Petenia, and Cryptoheros, with this clade forming a core group of amphilophines within the cichlid tribe Heroini.