Selective constraints in cold-region wild boars may defuse the effects of small effective population size on molecular evolution of mitogenomes
| Autor: | Jianlin Han, E. V. Kamaldinov, Shuhong Zhao, Jianhai Chen, V.L. Petukhov, Nikica Šprem, Pan Ni, Xiangdong Liu, Thuy Nhien Tran Thi |
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| Rok vydání: | 2018 |
| Předmět: |
0106 biological sciences
0301 basic medicine Nonsynonymous substitution endocrine system Sus scrofa Population Population genetics Zoology Biology Ka/Ks ratio 010603 evolutionary biology 01 natural sciences 03 medical and health sciences Sus scrofa Ka/Ks ratio purifying selection selective constraints mitogenomes Genetic drift Effective population size lcsh:QH540-549.5 education Ecology Evolution Behavior and Systematics Nature and Landscape Conservation Local adaptation education.field_of_study Natural selection mitogenome Ecology 030104 developmental biology selective constraint lcsh:Ecology purifying selection |
| Zdroj: | Ecology and Evolution, Vol 8, Iss 16, Pp 8102-8114 (2018) |
| ISSN: | 2045-7758 |
| Popis: | Spatial range expansion during population colonization is characterized by demographic events that may have significant effects on the efficiency of natural selection. Population genetics suggests that genetic drift brought by small effective population size (Ne) may undermine the efficiency of selection, leading to a faster accumulation of nonsynonymous mutations. However, it is still unknown whether this effect might be balanced or even reversed by strong selective constraints. Here, we used wild boars and local domestic pigs from tropical (Vietnam) and subarctic region (Siberia) as animal model to evaluate the effects of functional constraints and genetic drift on shaping molecular evolution. The likelihood‐ratio test revealed that Siberian clade evolved significantly different from Vietnamese clades. Different datasets consistently showed that Siberian wild boars had lower Ka/Ks ratios than Vietnamese samples. The potential role of positive selection for branches with higher Ka/Ks was evaluated using branch‐site model comparison. No signal of positive selection was found for the higher Ka/Ks in Vietnamese clades, suggesting the interclade difference was mainly due to the reduction in Ka/Ks for Siberian samples. This conclusion was further confirmed by the result from a larger sample size, among which wild boars from northern Asia (subarctic and nearby region) had lower Ka/Ks than those from southern Asia (temperate and tropical region). The lower Ka/Ks might be due to either stronger functional constraints, which prevent nonsynonymous mutations from accumulating in subarctic wild boars, or larger Ne in Siberian wild boars, which can boost the efficacy of purifying selection to remove functional mutations. The latter possibility was further ruled out by the Bayesian skyline plot analysis, which revealed that historical Ne of Siberian wild boars was smaller than that of Vietnamese wild boars. Altogether, these results suggest stronger functional constraints acting on mitogenomes of subarctic wild boars, which may provide new insights into their local adaptation of cold resistance. |
| Databáze: | OpenAIRE |
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