Limited genetic variation and structure in softshell clams (Mya arenaria) across their native and introduced range |
| |
Authors: | C A Strasser P H Barber |
| |
Institution: | (1) Biology Department, Woods Hole Oceanographic Institution, MS 34, Woods Hole, 02543, MA, USA;(2) Biology Department, Boston University, Boston, 02215, MA, USA |
| |
Abstract: | To offset declines in commercial landings of the softshell clam, Mya
arenaria, resource managers are engaged in extensive stocking of seed clams throughout its range in the northwest Atlantic. Because
a mixture of native and introduced stocks can disrupt locally adapted genotypes, we investigated genetic structure in M.
arenaria populations across its current distribution to test for patterns of regional differentiation. We sequenced mitochondrial
cytochrome oxidase I for a total of 212 individuals from 12 sites in the northwest Atlantic (NW Atlantic), as well as two
introduced sites, the northeast Pacific (NE Pacific), and the North Sea Europe (NS Europe). Populations exhibited extremely
low genetic variation, with one haplotype dominating (65–100%) at all sites sampled. Despite being introduced in the last
150–400 years, both NE Pacific and NS Europe populations had higher diversity measures than those in the NW Atlantic and both
contained private haplotypes at frequencies of 10–27% consistent with their geographic isolation. While significant genetic
structure (F
ST = 0.159, P < 0.001) was observed between NW Atlantic and NS Europe, there was no evidence for genetic structure across the pronounced
environmental clines of the NW Atlantic. Reduced genetic diversity in mtDNA combined with previous studies reporting reduced
genetic diversity in nuclear markers strongly suggests a recent population expansion in the NW Atlantic, a pattern that may
result from the retreat of ice sheets during Pleistocene glacial periods. Lack of genetic diversity and regional genetic differentiation
suggests that present management strategies for the commercially important softshell clam are unlikely to have a significant
impact on the regional distribution of genetic variation, although the possibility of disrupting locally adapted stocks cannot
be excluded. |
| |
Keywords: | Mya arenaria Bivalve COI Northwest Atlantic Genetic structure |
本文献已被 SpringerLink 等数据库收录! |
|