Molecular Genetic Analysis of Atlanto-Scandian Herring(Clupea Harengus)Populations Using Allozymes and Mitochondrial Dna Markers

Abstract

Allozymes and restriction fragment length polymorphisms (RFLP's) in genes of the NADH dehydrogenase complex (ND 5/6 genes) of mitochondrial DNA (mtDNA) were used to investigate the spatial genetic structure of Atlanto-Scandian herring (Clupea harengus). Samples (sample size=46–50/site) comprised Icelandic summer spawners, Norwegian spring spawners, and two fjord populations, Balsfjord and Trondheimsfjord, on the Norwegian coast. Fifty enzymes were assayed, and samples were routinely examined at 18 enzymes comprising 28 putative allozyme loci. Significant genetic differentiation (P < 0.001) was detected between Trondheimsfjord herring and all other samples, with apparent genetic homogeneity among remaining samples, including the Balsfjord; a region shown previously to contain an allozymically distinct population. Herring from the Balsfjord were shown allozymically to represent the Norwegian spring spawning group, suggesting the presence of two stocks, a deeper resident spawning (Balsfjord) and a shallower, non-native feeding population (Norwegian spring spawning). Variation at the ND5/6 genes using six restriction enzymes revealed 96 composite haplotypes in 196 fish. Mean haplotype diversity was high (0.92), though nucleotide divergence between samples was small (highest=0.00029, between Trondheimsfjord and Balsfjord samples; lowest=0.00003, between Icelandic summer and Balsfjord samples). Monte-Carlo %2 analysis of haplotype frequencies revealed no significant geographic heterogeneity among samples, thus revealing a discordant pattern of genetic differentiation produced by allozymes and mtDNA markers. The detection of a genetically divergent population in deeper waters of the Trondheimsfjord supports the existence of distinct deep-water resident populations in the Norwegian fjords.

Population genetic structure of the glacier lanternfish,Benthosema glaciale(Myctophidae) in Norwegian waters

“…General lack of genetic structuring on a large geographic scale in marine fish species contrasts with the localised genetic heterogeneity among fjord stocks and oceanic stocks reported in some species (herring Clupea harengus: Jørstad & Naevdal 1983, Turan & al. 1998; cod Gadus morhua: Jørstad & Naevdal 1989, Dahle 1991; blue whiting Micromesistius poutassou : Giaever & Stien 1998).…”

Functional consequences and population differences in the developmental plasticity of muscle to temperature in Atlantic herring Clupea harengus

“…6), as was reported previously for the 1995 and 1996 spawning seasons (Johnston et al 1997). On the basis of the genetic homogeneity reported for herring stocks (Ryman et al 1984, Turan et al 1998, we tested the hypothesis that a similar plasticity of neuromuscular development would be observed in other spawning populations. Multiple regression analysis and backward elimination of response variables indicated significant effects of pop, temp, egg and year on the development of myofibrils and AchE activity.…”

“…Atlantic herring show a high homing fidelity to their spawning grounds (Wheeler & Winters 1984), although there is evidence that spring spawning herring may turn into autumn spawners and vice versa (Anokhina 1971) indicating at least some gene flow between populations. Indeed, genetic studies using allozymes and mitochondrial markers indicate relatively little structuring between stocks (Jørstad & Naevdal 1981, Grant 1984, Ryman et al 1984, with the exception of isolated deep-water resident populations in Norwegian fjords (Jørstad et al 1994, Turan et al 1998. For example, Dahle & Erikson (1990), using restriction fragment length polymorphism (RFLP) analysis, found no genetic differentiation between autumn and spring spawning populations of herring in the North and Baltic Seas.…”

Genetic structure of the high dispersal Atlanto-Mediterreanean sea star Astropecten aranciacus revealed by mitochondrial DNA sequences and microsatellite loci

“…As the effective mitochondrial population size (N e ) is expected to be four times smaller than the nuclear N e , assuming both 1:1 sex ratios and diploidy (Birky et al 1983), there is a higher potential for genetic drift in mtDNA, which leads to a higher θ. Ratios significantly higher than fourfold can be caused by sex bias in migration, reproduction or population size or by a difference in the mutation rate of the two markers (Turan et al 1998;Shaw et al 1999). The average θ C / θ N ratio in A. aranciacus is slightly higher than fourfold, for which the mentioned possibilities of sex bias or differences in mutation rates, combined or separately, could be partly responsible.…”