| Mutations will continue to produce genetic variation into the population.People usually define the mutations that occur in organisms that can change the conserved sites in the system development or cause the loss of protein function as deleterious mutations.Many mutations that occur in the genome are weakly deleterious and reduce fitness,but these weakly deleterious mutations cannot be eliminated from the population by purifying natural selection.Therefore,it is of great interest to understand the reasons for the persistence of deleterious mutations in the group and the role of group history in this process.The domestication and breeding process of animals and plants will cause deleterious mutations to exist at a higher frequency.Therefore,identifying such deleterious mutations is particularly important for the domestication and improvement of animal and plant varieties.Sheep(Ovis aries)is one of the most important livestock and one of the earliest domesticated livestock domesticated by humans.Sheep are now spread all over the world.Humans began to domesticate sheep in the Fertile Crescent about 11,000 years ago,and then spread across the world.Sheep can provide humans with fur and meat products to meet human needs for production and living materials.The domestication of sheep is the development of agriculture and animal husbandry.Foundation.Therefore,it is particularly important to evaluate the frequency and distribution of deleterious mutations in the sheep genome and the function of deleterious mutant genes.This study took sheep as the research object.Based on the collected resequencing data of 233 domestic sheep and 36 wild sheep from all over the world,the frequency and distribution of deleterious mutations and the functions of deleterious mutation-related genes in the sheep population were identified and analyzed.In this study,a total of 20935 deleterious mutations were identified in domestic sheep and wild sheep,involving 7305 genes.The main findings are as follows:(1)This study found that a large number of putative deleterious mutations are carried in sheep populations,and these deleterious mutations mainly exist at low frequencies.Domestic populations show a higher proportion of deleterious mutations at low frequencies,suggesting that wild populations have accumulated a large number of deleterious mutations after domestication;in addition,our research results indicate that Chinese sheep may have accumulated more deleterious mutations than European sheep.Among Chinese sheep,Bayinbulak sheep,Hu sheep Cele black sheep and Ujumqin sheep have a higher percentage of enrichment to low frequency(MAF≤0.05).(2)Our analysis shows that the selective scanning area tends to accumulate more deleterious mutations than the non-scanning area,which indicates that artificial selection of important traits in animal husbandry may lead to the accumulation of deleterious mutations in the genes captured in the selected area.(3)Gene enrichment analysis showed that the genes with deleterious mutations in domestic sheep were mainly related to smell,detection of chemical stimulation,transmembrane signal transduction receptor activity,and G protein coupled receptor signaling pathway(P<0.05).To the best of our knowledge,these results provide a qualitative assessment of the increase in harmful mutation loads directly related to domestication,and are important for selective breeding programs and the protection of rare and endangered species.Specifically,they emphasized the costs associated with selective breeding and questioned the practice of using individuals best suited to breeding standards for breeding.This study initially explored the distribution of deleterious mutations in the sheep genome at the whole genome level,and comprehensively assessed the differences in harmful mutation sites between wild sheep and domestic sheep populations.It also found that domestic sheep populations are selected The main function of unique harmful genes.These results provide a theoretical basis for the study of deleterious mutations in sheep,and also provide useful data for further improving the fitness of sheep populations and promoting the improvement of animal breeding. |
