High Incidence of a Male-Specific Genetic Marker in Phenotypic Female Chinook Salmon from the Columbia River

Numerous populations of anadromous salmonids in the northwestern United States have been declining for many years, resulting in Endangered Species Act listings and in some cases extinction. The degradation of river ecosystems has been proposed as one of the major reasons for the inability of salmon...

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Bibliographic Details
Published in:Environmental health perspectives 2001-01, Vol.109 (1), p.67-69
Main Authors: Nagler, James J., Bouma, Jerry, Thorgaard, Gary H., Dauble, Dennis D.
Format: Article
Language:English
Subjects:
Anadromous fishes
Animals
Brackish
Dams
Disorders of Sex Development
DNA
DNA - analysis
Environmental Exposure
Estrogens
Female
Freshwater
Freshwater fishes
Genetic Markers
Male
Marine
Oncorhynchus - genetics
Oncorhynchus tshawytscha
Phenotype
Polymerase Chain Reaction
Priests
Salmon
Sex chromosomes
Sex determination
Water Pollutants, Chemical - adverse effects
Y chromosome
Y Chromosome - genetics
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Summary:Numerous populations of anadromous salmonids in the northwestern United States have been declining for many years, resulting in Endangered Species Act listings and in some cases extinction. The degradation of river ecosystems has been proposed as one of the major reasons for the inability of salmon to maintain their populations. However, the specific factors interfering with the reproduction and survival of salmon during the freshwater phase of their life cycle have not been fully described. This study was initiated to determine the incidence of phenotypic sex reversal in wild, fall chinook salmon (Oncorhynchus tshawytcha) that returned to spawn in the Columbia River. Fish were sampled at different locations within this watershed to determine whether they were faithfully expressing their genotype. We report a high incidence (84%) of a genetic marker for the Y chromosome in phenotypic females sampled from the wild, which was not observed in female fish raised in hatcheries. It appears likely that female salmon with a male genotype have been sex reversed, creating the potential for an abnormal YY genotype in the wild that would produce all-male offspring and alter sex ratios significantly.
ISSN:0091-6765
1552-9924
DOI:10.1289/ehp.0110967