Journal of Genetics and Genomics最新文献

Yunnan in southwest China is a geographically and ethnically complex region at the intersection of southern China and Southeast Asia, and a focal point for human migrations. To clarify its maternal genetic history, we generated 152 complete mitogenomes from 17 Yunnan archaeological sites. Our results reveal distinct genetic histories segregated by geographical regions. Maternal lineages of ancient populations from northwestern and northern Yunnan exhibit closer affinities with past and present-day populations from northern East Asia and Tibet, providing important genetic evidence for the migration and interaction of populations along the Tibetan-Yi corridor since the Neolithic. Between 5500 to 1800 years ago, central Yunnan populations maintained their internal genetic relationships, including a 7000-year-old basal lineage of the rare and widely dispersed haplogroup M61. At the Xingyi site, changes in mitochondrial DNA haplogroups occurred between the Late Neolithic and Bronze Age, with haplogroups shifting from those predominant in the Yellow River region to those predominant in coastal southern China. These results highlight the high diversity of Yunnan populations during the Neolithic to Bronze Age.

On top of genetic information, organisms have evolved complex and sophisticated epigenetic regulation to adjust gene expression in response to developmental and environmental signals. Key epigenetic mechanisms include DNA methylation, histone modifications and variants, chromatin remodeling, and chemical modifications of RNAs. Epigenetic control of environmental responses is particularly important for plants, which are sessile and unable to move away from adverse environments. Besides enabling plants to rapidly respond to environmental stresses, some stress-induced epigenetic changes can be maintained, providing plants with a pre-adapted state to recurring stresses. Understanding these epigenetic mechanisms offers valuable insights for developing crop varieties with enhanced stress tolerance. Here, we focus on abiotic stresses and summarize recent progress in characterizing stress-induced epigenetic changes and their regulatory mechanisms and roles in plant abiotic stress resistance.

Chicken body weight (BW) is a critical trait in breeding. Although genetic variants associated with BW have been investigated by genome-wide association studies (GWAS), the contributions of causal variants and their molecular mechanisms remain largely unclear in chickens. In this study, we construct a comprehensive genetic atlas of chicken BW by integrative analysis of 30 age points and 5 quantitative trait loci (QTL) across 27 tissues. We find that chicken growth is a cumulative non-linear process, which can be divided into three distinct stages. Our GWAS analysis reveals that BW-related genetic variations show ordered patterns in these three stages. Genetic variations in chromosome 1 may regulate the overall growth process, likely by modulating the hypothalamus-specific expression of SLC25A30 and retina-specific expression of NEK3. Moreover, genetic variations in chromosome 4 and chromosome 27 may play dominant roles in regulating BW during Stage Ⅱ (8-22 weeks) and Stage Ⅲ (23-72 weeks), respectively. In summary, our study presents a comprehensive genetic atlas regulating developmental stage-specific changes in chicken BW, thus providing important resources for genomic selection in breeding programs.

CtBP-interacting protein (CtIP) is known for its multifaceted roles in DNA repair and genomic stability, directing the homologous recombination-mediated DNA double-stranded break (DSB) repair pathway via DNA end resection, an essential error-free repair process vital for genome stability. Mammalian oocytes are highly prone to DNA damage accumulation due to prolonged G2/prophase arrest. Here, we explore the functions of CtIP in meiotic cell cycle regulation via a mouse oocyte model. Depletion of CtIP by siRNA injection results in delayed germinal vesicle breakdown and failed polar body extrusion. Mechanistically, CtIP deficiency increases DNA damage and decreases the expression and nuclear entry of CCNB1, resulting in marked impairment of meiotic resumption, which can be rescued by exogenous CCNB1 overexpression. Furthermore, depletion of CtIP disrupts MTOCs coalescence at spindle poles as indicated by failed accumulation of γ-tubulin, p-Aurora kinase A, Kif2A, and TPX2, leading to abnormal spindle assembly and prometaphase arrest. These results provide valuable insights into the important roles of CtIP in the G2/M checkpoint and spindle assembly in mouse oocyte meiotic cell cycle regulation.