Mj. Bagley et Gae. Gall, MITOCHONDRIAL AND NUCLEAR-DNA SEQUENCE VARIABILITY AMONG POPULATIONS OF RAINBOW-TROUT (ONCORHYNCHUS-MYKISS), Molecular ecology, 7(8), 1998, pp. 945-961
Mitochondrial and nuclear DNA variability was examined to assess popul
ation genetic structure and phylogeographic relationships in rainbow t
rout. Single-strand conformation polymorphisms and restriction site di
fferences within 1055 bp of the mitochondrial D-loop region and 1566 b
p of nuclear DNA in six single-copy nuclear DNA regions identified 31
mitochondrial genotypes and 50 nuclear alleles. Gene trees were constr
ucted by sequencing each variant allele or mitochondrial genotype iden
tified. Examination of 30 populations in 10 native rainbow trout group
s using an analysis of molecular variance (AMOVA) indicated that 65% o
f mitochondrial variability and 35% of nuclear variability was explain
ed by differences among the 10 groups. Phylogenetic patterns evident i
n mitochondrial and nuclear DNA were not always concordant. Difference
s in the evolutionary patterns detected by mitochondrial and nuclear D
NA may reflect the differential impact of past introgression events on
variability in the two genomes.