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Subtle population structuring within a highly vagile marine invertebrate, the veined squid Loligo forbesi , demonstrated with microsatellite DNA markers
Author(s) -
SHAW P. W.,
PIERCE G. J.,
BOYLE P. R.
Publication year - 1999
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1046/j.1365-294x.1999.00588.x
Subject(s) - biology , microsatellite , population , gene flow , biological dispersal , genetic variation , zoology , population genetics , genetic structure , effective population size , evolutionary biology , genetics , allele , gene , demography , sociology
Microsatellite DNA markers were applied for the first time in a population genetic study of a cephalopod and compared with previous estimates of genetic differentiation obtained using allozyme and mitochondrial DNA (mtDNA) markers. Levels of genetic variation detected with microsatellites were much higher than found with previous markers (mean number of alleles per locus=10.6, mean expected heterozygosity ( H E )=0.79; allozyme H E =0.08; mtDNA restriction fragment length polymorphism (RFLP) H E =0.16). In agreement with previous studies, microsatellites demonstrated genetic uniformity across the population occupying the European shelf seas of the North East Atlantic, and extreme genetic differentiation of the Azores population ( R ST / F ST =0.252/0.245; allozyme F ST =0.536; mtDNA F ST =0.789). In contrast to other markers, microsatellites detected more subtle, and significant, levels of differentiation between the populations of the North East Atlantic offshore banks (Rockall and Faroes) and the shelf population ( R ST =0.048 and 0.057). Breakdown of extensive gene flow among these populations is indicated, with hydrographic (water depth) and hydrodynamic (isolating current regimes) factors suggested as possible barriers to migration. The demonstration of genetic subdivision in an abundant, highly mobile marine invertebrate has implications for the interpretation of dispersal and population dynamics, and consequent management, of such a commercially exploited species. Relative levels of differentiation indicated by the three different marker systems, and the use of measures of differentiation (assuming different mutation models), are discussed.