A small-insert library was constructed after microdissection of the short arm of the Y chromosome of lake charr, Salvelinus namaycush. Clones from this library were sequenced and two dinucleotide CA-repeat microsatellite sequences were recovered. Oligonucleotide primers for one locus were designed and optimized for amplification by PCR. This locus (designated Yp136) was tested for sex linkage in twelve lake charr families and found to be a distance of 37 centimorgans (cM) from the sex-determining locus. This microsatellite locus was also examined in three informative, gynogenetic/diploid, lake charr crosses for linkage to the centromere on the X chromosome. Results from these families show that this locus is 19 cM from the centromere. The combination of linkage data and microdissection information places the sex-determining locus near the telomere of the Y chromosome in lake charr. This is consistent with studies of several other fish species including some salmonids that place the sex locus near the telomere.
- Sex locus