Natural variability of minimotifs in 1092 people indicates that minimotifs are targets of evolution |
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Authors: | Kenneth F. Lyon Christy L. Strong Steve G. Schooler Richard J. Young Nervik Roy Brittany Ozar Mark Bachmeier II Sanguthevar Rajasekaran Martin R. Schiller |
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Affiliation: | 1.Nevada Institute of Personalized Medicine and School of Life Sciences, University of Nevada Las Vegas, 4505 Maryland Parkway, Las Vegas, NV 89154-4004, USA;2.Department of Computer Science and Engineering, University of Connecticut, Storrs, CT 06269-2155, USA |
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Abstract: | Since the function of a short contiguous peptide minimotif can be introduced or eliminated by a single point mutation, these functional elements may be a source of human variation and a target of selection. We analyzed the variability of ∼300 000 minimotifs in 1092 human genomes from the 1000 Genomes Project. Most minimotifs have been purified by selection, with a 94% invariance, which supports important functional roles for minimotifs. Minimotifs are generally under negative selection, possessing high genomic evolutionary rate profiling (GERP) and sitewise likelihood-ratio (SLR) scores. Some are subject to neutral drift or positive selection, similar to coding regions. Most SNPs in minimotif were common variants, but with minor allele frequencies generally <10%. This was supported by low substation rates and few newly derived minimotifs. Several minimotif alleles showed different intercontinental and regional geographic distributions, strongly suggesting a role for minimotifs in adaptive evolution. We also note that 4% of PTM minimotif sites in histone tails were common variants, which has the potential to differentially affect DNA packaging among individuals. In conclusion, minimotifs are a source of functional genetic variation in the human population; thus, they are likely to be an important target of selection and evolution. |
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