Deletion and Copy Number Variation of Y‐Chromosomal Regions in Coho Salmon, Chum Salmon, and Pink Salmon Populations

AbstractThe linkage between the Y-chromosomal DNA marker GH-Y (growth hormone pseudogene) and the Y-associated sex-determining locus was examined in 31 populations of Coho Salmon Oncorhynchus kisutch, 29 populations of Chum Salmon O. keta, and 14 populations of Pink Salmon O. gorbuscha from North America (British Columbia [BC] and Yukon, Canada; Oregon and Washington, USA) and Japan to examine the stability of Y-chromosome sequences in salmonids. This marker is used for genetic sexing of multiple salmon species both for population studies and for aquaculture strain development. We found a strong association between GH-Y and sex in Coho Salmon (with rare exceptions seen in Washington and Oregon only), whereas the association of GH-Y and sex was weak in Chum Salmon and Pink Salmon. Up to 100% of males lacking GH-Y were found in some BC Chum Salmon populations, whereas there were no exceptional (GH-Y-negative) males in Japan, the Yukon, or Washington, indicating strong geographic clustering of GH-Y marker de...