title: Heteromorphic sex chromosomes in male rainbow trout.
abstract: A pair of subtelocentric chromosomes differs in the size of the short arm in male, but not female, rainbow trout (Salmo gairdneri). The morphological similarity of the X and Y chromosomes, and the observation of Y chromosomes intermediate between the X and normal Y, suggest that the sex chromosomes are at an early stage of differentiation in this species.
mesh_terms: D000818:Animals; D005075:Biological Evolution; D005260:Female; D007621:Karyotyping; D008297:Male; D012487:Salmonidae / Q000033:anatomy & histology*; D012730:Sex Chromosomes / Q000648:ultrastructure*; D014337:Trout / Q000033:anatomy & histology*