Why mice have lost genes for COL21A1, STK17A, GPR145 and AHRI:: evidence for gene deletion at evolutionary breakpoints in the rodent lineage

The mouse genome has undergone extensive chromosome rearrangement relative to the human genome since these species last shared a common ancestor. One possible consequence of these rearrangements is the deletion of genes that are located within evolutionary breakpoint regions. In this article, we present evidence of four human genes (COL21A1, STK17A, GPR145 and ARHI) that are located in regions corresponding to evolutionary breakpoints in rodents and lack mouse and rat orthologues. We propose that 'evolutionary breakpoint-associated gene deletion' is an unexpected consequence of evolutionary chromosome rearrangement, and we describe a novel mechanism through which genes can be lost during evolution.