3/15/2023 0 Comments Whm template for 010 editor![]() An improved knowledge of cen-satDNA diversity is a crucial first step toward understanding the potential phenotypic consequences of variation in species lineages. Whereas variability in cen-satDNA has been shown to have a pivotal effect on phenotypic constraints in vertebrates such as mice, with the bias of non-Mendelian chromosome transmission in heterozygotes, known as centromere drive in the population. The structure and content of alpha-satDNA in primates have changed rapidly over relatively short periods of evolutionary time. Primate species comparison of alpha-satDNA has revealed that human alpha-satDNA shares 80–86% identity with that of chimpanzees ( Pan troglodytes, Blumenbach, 1775), western gorillas ( Gorilla gorilla, Savage, 1847), and Sumatran orangutans ( Pongo abelii, Lesson, 1827), indicating the presence of alpha-satDNA in a common primate ancestor. The organization and unit of periodicity of these arrays are specific to each primate species or chromosome. Alpha-satDNA variants have been associated with differences in the stability of kinetochore protein binding, affecting the fidelity of chromosome segregation. Interestingly, satDNA varieties can exist within a single satDNA family, known as subfamilies, with each one being represented by a specific repetitive sequence.Ĭen-satDNA sequences, which occupy a substantial portion of primate centromeres, are mainly constituted by “alpha-satellite” arrays. Varieties among satDNA families are attributed to mutation rate, species, chromosome morphology, population size, and reproductive mode. Natural selection could drive the biased amplification of one satDNA family more than others. Following “the library model”, different satDNA families can efficiently change the arrangement of DNA sequences in heterochromatin by replacing one dominant satDNA family with another that is less well represented and differs in nucleotide sequences or copy numbers in related species. ![]() Two families located in the same genome are highly similar they maintain the integrity of each specific individual family and exhibit high homogeneity of repetitive sequences. Different satDNA variants might exist within the genome of a species as a consequence of satDNA turnover mechanisms, leading to the emergence of new specific satDNA families. Multiple satDNA copies exhibit higher similarity within a species, termed familial satDNA, as opposed to within the same satDNA sequence pattern of related species in concerted evolution. Several mechanisms have been postulated for this homogenization, including gene conversion and unequal crossing over. Within a species, many satDNA copies have been shown to undergo a process known as molecular drive that homogenizes the sequence within the genome, subsequently fixing it in the sexual population. These processes actively contribute to variability in the repeat size, number, and nucleotide sequences between species or populations, and also result in the appearance of epigenetic modifications in centromeric satDNA (cen-satDNA), affecting centromeric functions. Owing to this satellite-rich architecture, centromeres tend to have high rates of structural mutations that occur through replication slippage, unequal crossing over, and transposition. ![]() Centromeric DNA is mainly composed of tandem arrays of repetitive DNA sequences with multiple repeat units known as satellite DNA (satDNA). Our study provides a genomic landscape of centromeric repeats in wild macaques and opens new avenues for exploring their impact on the adaptive evolution and speciation of primates.Ĭentromeres are essential chromatin domains for chromosome segregation during cell division and for the maintenance of genome stability across eukaryotes. However, differences in cen-satDNA profiles appear to not be involved in hybrid incompatibility between the two species. Population structure analysis detected admixture patterns within populations, indicating their high divergence and rapid evolution. Comparative genomics identified high level polymorphisms spanning a 120 bp deletion region and a remarkable interspecific variability in cen-satDNA size and structure. Fluorescence in situ hybridization and bioinformatic analysis showed the chromosome-specific organization and dynamic nature of cen-satDNAsequences, and their substantial diversity, with distinct subfamilies across macaque populations, suggesting increased turnovers. Here, we investigated the genetic diversity in the centromeric region of two primate species: long-tailed ( Macaca fascicularis) and rhesus ( Macaca mulatta) macaques. Centromeric satellite DNA (cen-satDNA) consists of highly divergent repeat monomers, each approximately 171 base pairs in length.
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