Identification of the Arctic char sex-determining chromosome

Sex-determination is the most pivotal developmental process in the life of a gonochoristic organism. The purpose of this thesis was to identify the sex chromosomes in Arctic char (Salvelinus alpinus). The sex-determining gene, SEX, was mapped to Arctic char linkage group 4 (AC-4). I have used probes designed from flanking regions of sex-linked markers to screen a fosmid library. Fosmids containing sex-linked markers were isolated and placed on Arctic char chromosomes by FISH, identifying chromosome 3 as the sex chromosome. A fosmid containing Sal05SFU was particularly informative in this analysis and was sequenced using a combination of shotgun cloning and selected primer walking. Annotation of the Sal05SFU sequence identified the first five exons of Suppressor of fused (Sufu), a candidate sex-determining gene. Additional candidate genes for sex-determination were identified through comparative genome analysis.