Pig Genome Evolution: Chromosomal Rearrangements and their Impact on Gene Networks

The genome sequencing and chromosomal assembling of various mammalian genomes opens a unique opportunity to study evolution in mammals and connect chromosomal rearrangements to adaptive changes gained by each species’ genome during speciation. In the present study we performed classification of pig– specific evolutionary breakpoint regions (EBRs) using a newly developed algorithm. This led to detection of 192 pig EBRs. We later analyzed human gene content in and around the pig EBRs and found significant enrichment for the gene ontology categories related to sensory perception of taste, and keratinisation (FDR < 0.05; P < 0.05). This makes the pig genome different from the most other mammalian genomes where EBRs are commonly associated with the immune response genes duplicated by segmental duplications associated with genomic rearrangements. We also analyzed transposable elements distribution in the pig genome and found that LTR-ERV1 elements and satellite repeats contributed to formation of pig lineages-specific EBRs, while tRNA Glu-derived SINEs were uniquely involved formation of ancestral artiodactyl rearrangements (shared by pig and cattle). Extended to other genomes our approach will demonstrate how transposon activity associated with chromosomal rearrangements produces variations in gene networks used by the natural selection.