Polymorphism and differentiation of rainbow trout Y chromosomes.
Most fish species show little morphological differentiation in the sex chromosomes. We have coupled molecular and cytogenetic analyses to characterize the male-determining region of the rainbow trout (Oncorhynchus mykiss) Y chromosome. Four genetically diverse male clonal lines of this species were used for genetic and physical mapping of regions in the vicinity of the sex locus. Five markers were genetically mapped to the Y chromosome in these male lines, indicating that the sex locus was located on the same linkage group in each of the lines. We also confirmed the presence of a Y chromosome morphological polymorphism among these lines, with the Y chromosomes from two of the lines having the more common heteromorphic Y chromosome and two of the lines having Y chromosomes morphologically similar to the X chromosome. The fluorescence in situ hybridization (FISH) pattern of two probes linked to sex suggested that the sex locus is physically located on the long arm of the Y chromosome. Fishes appear to be an excellent group of organisms for studying sex chromosome evolution and differentiation in vertebrates because they show considerable variability in the mechanisms and (or) patterns involved in sex determination.
Felip
Alicia
A
School of Biological Sciences and Center for Reproductive Biology, Washington State University, Pullman, WA 99164, USA.
Fujiwara
Atushi
A
Young
William P
WP
Wheeler
Paul A
PA
Noakes
Marc
M
Phillips
Ruth B
RB
Thorgaard
Gary H
GH
D000818:Animals; D002874:Chromosome Mapping; D008040:Genetic Linkage; D005819:Genetic Markers; D005838:Genotype; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008297:Male; D017686:Oncorhynchus mykiss; D010802:Phylogeny; D020161:Physical Chromosome Mapping; D011110:Polymorphism, Genetic; D019849:Sex Determination Processes; D014998:Y Chromosome
D005819:Genetic Markers