Copy Number Variation in Livestock and Companion Animals: A Window to Domestication and Other Evolutionary Processes

The combination of SNP chip arrays, comparative genomic hybridization and next generation sequencing data has allowed the identification of extensive copy number variation (CNV) in domestic species. Structural variation could result in the loss/gain of functional and regulatory elements contributing to genetic changes associated with evolutionary processes, such as domestication and artificial selection, that are or have been at play for millenia. In this regard, the comparison of CNV in domestic animals and their wild progenitors is particularly relevant to understand the genetic basis of the behavioral and phenotypic modifications involved in domestication. A general hallmark of surveys performed in livestock species and dogs is that CNV regions are particularly enriched in genes related to neurological functions. However, pig vs wild boar and dog vs wolf comparisons have not revealed any strong candidate CNV to explain the behavioral changes that favoured the establishment of a long-term relationship with humans. Elusive processes as polygenic adaptation and soft sweeps might have been the major driving forces modifying neurological functions of domesticates. Furthermore, convincing causal effects have been demonstrated between CNVs and a wide array of phenotypes that were targeted by artificial selection during or after domestication e.g.pigmentation in pigs, sheep, chicken and horses; fertility in cattle and goats; feathering and comb shape in chicken and susceptibility to diseases in many species. Indeed, structural information will be crucial for understanding the genetic basis of the extraordinary diversity that we currently see amongst breeds and it could have potential applications in genetic improvement.  

Back to: Plant and Animal Paleogenomics

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