Genetic diversity of two salmonid species, Dolly Varden (Salvelinus
malma) and coastal cutthroat trout (Oncorhynchus clarki clarki) in Prince William
Sound, Alaska were examined at multiple spatial scales with three molecular
markers. Pleistocene glaciers covered what is now Prince William Sound 8,000-
12,000 years ago and both species colonized the region subsequently. Because
these species have different migratory behavior and historic ranges I expected to
see different patterns of genetic diversity within Prince William Sound. Haplotype
frequency and nucleotide diversity in sixteen mitochondrial DNA (mtDNA)
restriction fragment enzymes combinations in Prince William Sound were higher in
Dolly Varden than in coastal cutthroat trout, which were close to fixation. Low
estimates of these measures in coastal cutthroat trout may reflect a founder effect
resulting from colonization of this region from a single glacial refuge (Cascadia)
and low dispersal capacity. To examine if genetic diversity in coastal cutthroat
trout was higher in areas of glacial refuge, three additional locations from
throughout their distributional range were examined with the same restriction
enzymes. Haplotype frequency and nucleotide diversity were lower in areas that
were glaciated than estimates of the same measures in a glacial refuge. Again,
founder effects during colonization of the three glaciated sites may account for
these results. Genetic variation of Dolly Varden and coastal cutthroat trout was
also examined within and among populations in Prince William Sound with
microsatellites and allozymes. The pattern of genetic variation in coastal cutthroat
trout was complex. There was lower genetic diversity within populations that were
recently colonized following recent de-glaciation (150-350 ybp). Genetic diversity
among some coastal cutthroat trout populations was high, which possibly reflects
restricted migration. In other trout populations there was low diversity among
populations, possible reflecting historic gene flow. In Dolly Varden, genetic
variation among anadromous populations in Prince William Sound was low. There
were large differences among resident and anadromous populations. These data
provide information for the management for both species, which may reduce the
risk of the loss of genetic diversity within local populations. / Graduation date: 2003
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/26039 |
| Date | 13 June 2002 |
| Creators | Griswold, Kitty E. |
| Contributors | Reeves, Gordon H. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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