Widespread ultraconservation divergence in primates.
The distribution and evolution of ultraconserved elements (UCEs, DNA stretches that are perfectly identical in primates and rodents) were examined in genomes of 3 primate species (human, chimpanzee, and rhesus macaque). It was found that the number of UCEs has decreased throughout primate evolution. At least 26% of ancestral UCEs have diverged in hominoids, whereas an additional 17% have accumulated one or more single nucleotide polymorphisms in the human genome. Sequence polymorphism analyses indicate that mutation fixation within an UCE can trigger a relaxation in the selective constraint on that element. Homogeneous mutation accumulations in UCEs served as a template by which purifying selection acted more effectively on protein-coding UCEs. Gene ontology annotation suggests that UCE sequence variation, primarily occurring in noncoding regions, might be linked to the reprogramming of the expression pattern of transcription factors and developmentally important genes. Many of these genes are expressed in the central nervous system. Finally, UCE sequence variability within human populations has been identified, including population-specific nonsynonymous changes in protein-coding regions.
Ovcharenko
Ivan
I
Computational Biology Branch, National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA. ovcharei@ncbi.nlm.nih.gov
D000818:Animals; D002490:Central Nervous System / Q000378:metabolism; D019295:Computational Biology; D017124:Conserved Sequence / Q000235:genetics*; D030541:Databases, Genetic; D019143:Evolution, Molecular; D014644:Genetic Variation; D005828:Genetics, Population; D006801:Humans; D008253:Macaca mulatta / Q000235:genetics*; D008957:Models, Genetic; D002679:Pan troglodytes / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D013045:Species Specificity