Jc. Meyran et al., ENVIRONMENTAL CALCIUM, AND MITOCHONDRIAL-DNA POLYMORPHISM AMONG LOCAL-POPULATIONS OF GAMMARUS-FOSSARUM (CRUSTACEA, AMPHIPODA), Molecular ecology, 7(10), 1998, pp. 1391-1400
Mitochondrial DNA sequence analysis was used to investigate genetic di
versity and phylogeographic population structure among geographically
isolated alpine populations of the amphipod Gammarus fossarum. This st
udy was performed across a region with an important glacial history an
d substantial geographical variations in calcium levels, in order to e
valuate the relative impact on the genetic diversity of the population
history and this environmental factor known to be associated with loc
al adaptation and population growth. Analysis of the nucleotide sequen
ces for a 376-bp segment of the cytochrome c oxidase I gene in 84 spec
imens from seven different populations revealed 20 different haplotype
s distributed into five major lineages that are not geographically str
uctured. Analysis of molecular variance indicates that the populations
from the crystalline massif are less diverse than those living on lim
estone, suggesting a global correlation between genetic diversity and
calcium concentration of the water. However, the role of this environm
ental factor appears to be indirect, with Smaller population size lead
ing to lower genetic diversity.