Abstract
Highlights 13 A new theory for Y degeneration, not based on selective interference 14 Initiated by X and Y cis-regulator divergence after the arrest of recombination 15 Works faster and in larger populations than current theory 16 Works on small non-recombining region on the Y 17 eTOC Blurb 18 Y chromosomes are often degenerate. This remarkable feature of the genome of plants and 19 animals has been intensely investigated. Current theory proposes that this degeneration occurs 20 from "selective interference" after the arrest of recombination between the X and Y 21 chromosome, meaning that natural selection tends to be inefficient in the absence of 22 recombination. This theory has been in place for more than 40 years. In this paper, we propose a 23