Open AccessINTROGRESSION BETWEEN TWO CUTTHROAT TROUT SUBSPECIES WITH SUBSTANTIAL KARYOTYPIC, NUCLEAR AND MITOCHONDRIAL GENOMIC DIVERGENCE
Author(s) -
Ulf Gyllensten,
Robb F. Leary,
Fred W. Allendorf,
Allan C. Wilson
Publication year - 1985
Publication title -
genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.792
H-Index - 246
eISSN - 1943-2631
pISSN - 0016-6731
DOI - 10.1093/genetics/111.4.905
Subject(s) - biology , subspecies , introgression , mitochondrial dna , genetics , nuclear gene , evolutionary biology , genetic divergence , genome , linkage disequilibrium , trout , backcrossing , zoology , genetic diversity , genotype , gene , haplotype , population , fishery , fish <actinopterygii> , demography , sociology
The authors used allozymes encoded by nuclear genes and restriction enzyme analysis of mitochondrial DNA (mtDNA) to study secondary contact between westslope (Salmo clarki lewisi) and Yellowstone cutthroat trout (Salmo clarki bouvieri) in Forest Lake, Montana. Eleven diagnostic allozyme loci identified this as a random-mating hybrid swarm. No parental, first-generation hybrid or backcross genotypes were detected in the sample (N = 33), and genotype distributions at all the variable loci conform to binomial expectations. There is little linkage disequilibrium between the diagnostic loci, indicating that the nuclear genomes of the two subspecies are largely randomly associated. The allozymes and mtDNA give identical estimates of the proportional genetic contribution of each subspecies. Thus, males and females from both subspecies have contributed equally to this hybrid swarm. Although these subspecies have accumulated substantial genetic divergence between their nuclear (Nei's D = 0.34) and mitochondrial (2% sequence divergence) genomes, this has not resulted in a genetic barrier to exchange between them.