Population structure of odd‐broodline Asian pink salmon and its contrast to the even‐broodline structure

Abstract

Most of the variation (99%) of Asian odd-broodline pink salmon Oncorhynchus gorbuscha, based on data at 32 variable (46 total) allozyme loci from 35 populations, occurred within populations. The remaining interpopulation variation was attributable to: (1) differences between northern (the northern Sea of Okhotsk, eastern Kamchatka Peninsula and western Kamchatka Peninsula) and southern (Hokkaido Island, Kuril Islands and Sakhalin Island) populations; (2) differences between the southern areas; (3) low variation among populations within some areas. The pattern contrasted strongly with that observed for Asian evenbroodline populations, which had a strong structure, possibly related to geographic and oceanographic influences. Isolation-by-distance analyses of each of the two broodlines showed a stronger relationship ( 4·8) among even-than odd-broodline populations. Allele frequency differences between even-and odd-broodlines reflected the reproductive isolation of the broodlines. However, there were no fixed frequency differences which, considered with the differing population structures, suggests that migration-drift equilibrium has not yet obtained in one or both broodlines. The structural differences also suggest it is likely that the even-and odd-broodlines are of different ages and that one is derived from the other. Allozyme data do not provide a genealogical basis for identifying the ancestral lineage.

Estimating F-Statistics

“…In 1984, Weir & Cockerham (100) published a set of equations for estimating the parameter F ST or θ that describes the genetic structure of populations. The paper is still widely cited; in the first three months of 2002 the methods it described were applied to data on ash trees (59), Barbus (86), barley (42), barnacle (22), butterfly (18), cherry (54), cod (44), cord grass (85), Drosophila (32), eelgrass (64), frog (84), housefly (23), insects (58,103), ladybird beetle (92), mackerel (11), moose (41), mountain lion (24), pig (45), pine (66,68), quelea (19), red drum (33), redfish (72), river otter (9), rodent (14), salmon (37), scallops (67), sea trout (94), seaweed (88), shrimp (28), snail (13), stonefly (76), sugar beet (89), trout (38,48), tsetse fly (47), wombat (7), zooplankton (34), and humans (1,36,53) among other species. Population biologists, ecologists and human geneticists have a substantial interest in being able to quantify the genetic relationships among their populations; it is therefore timely to ...…”

Microsatellite variation reveals fine‐scale genetic structure of masu salmon, Oncorhynchus masou, within the Atsuta River

“…The extent of genetic structure and the level of genetic differentiation are highly influenced by the organism's life history and migratory abilities. Morán et al 1995;King et al 2001;Hawkins et al 2002). Such restricted homing behaviour limits gene flow between populations and promotes the formation of distinct populations that often exhibit both genetic and phenotypic adaptations to local environment (Taylor 1991;Quinn 1993;Stearns & Hendry 2004).…”

“…A number of studies focused on population genetic structure have investigated among populations between river systems and have documented significant genetic heterogeneity and genetic structuring (e.g. Morán et al 1995;King et al 2001;Hawkins et al 2002). As a result of these studies, a negative relationship between gene flow and geographical distance among populations suggest that isolation by distance (IBD) is applicable and the degree of such a relationship is variable dependent on the geographical distance among populations (reviewed by Hendry et al 2004).…”

Parallel signatures of selection in temporally isolated lineages of pink salmon

“…Moreover, pink salmon (Oncorhynchus gorbuscha) offer a unique opportunity to investigate parallel signals of selection and adaptation; they are semelparous and follow a strict two-year life cycle, resulting in two reproductively isolated lineages breeding in even and odd years. The divergence and isolation between the lineages have been consistently revealed by allozyme and microsatellite studies (Aspinwall 1974;Olsen et al 1998;Hawkins et al 2002;Beacham et al 2012). These studies, using putatively neutral markers, suggest that the even-and odd-year lineages have independently colonized their contemporary ranges.…”