• We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
Logo of geneticsGeneticsCurrent IssueInformation for AuthorsEditorial BoardSubscribeSubmit a Manuscript
Genetics. Jan 1995; 139(1): 375–385.
PMCID: PMC1206334

Genetic Population Structure and Gene Flow in the Atlantic Cod Gadus Morhua: A Comparison of Allozyme and Nuclear RFLP Loci

Abstract

High levels of gene flow have been implicated in producing uniform patterns of allozyme variation among populations of many marine fish species. We have examined whether gene flow is responsible for the limited population structure in the Atlantic cod, Gadus morhua L., by comparing the previously published patterns of variation at 10 allozyme loci to 17 nuclear restriction fragment length polymorphism (RFLP) loci scored by 11 anonymous cDNA clones. Unlike the allozyme loci, highly significant differences were observed among all populations at the DNA markers in a pattern consistent with an isolation-by-distance model of population structure. The magnitude of allele frequency variation at the nuclear RFLP loci significantly exceeded that observed at the protein loci (χ(2) = 24.6, d.f. = 5, P < 0.001). Estimates of gene flow from the private alleles method were similar for the allozymes and nuclear RFLPs. From the infinite island model, however, estimates of gene flow from the DNA markers were fivefold lower than indicated by the proteins. The discrepancy between gene flow estimates, combined with the observation of a large excess of rare RFLP alleles, suggests that the Atlantic cod has undergone a recent expansion in population size and that populations are significantly displaced from equilibrium. Because gene flow is a process that affects all loci equally, the heterogeneity observed among populations at the DNA level eliminates gene flow as the explanation for the homogeneous allozyme patterns. Our results suggest that a recent origin of cod populations has acted to constrain the extent of population differentiation observed at weakly polymorphic loci and implicate a role for selection in affecting the distribution of protein variation among natural populations in this species.

Full Text

The Full Text of this article is available as a PDF (1.7M).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Arnason E, Rand DM. Heteroplasmy of short tandem repeats in mitochondrial DNA of Atlantic cod, Gadus morhua. Genetics. 1992 Sep;132(1):211–220. [PMC free article] [PubMed]
  • Bowcock AM, Ruiz-Linares A, Tomfohrde J, Minch E, Kidd JR, Cavalli-Sforza LL. High resolution of human evolutionary trees with polymorphic microsatellites. Nature. 1994 Mar 31;368(6470):455–457. [PubMed]
  • Cavalli-Sforza LL. Population structure and human evolution. Proc R Soc Lond B Biol Sci. 1966 Mar 22;164(995):362–379. [PubMed]
  • Crow JF, Aoki K. Group selection for a polygenic behavioral trait: estimating the degree of population subdivision. Proc Natl Acad Sci U S A. 1984 Oct;81(19):6073–6077. [PMC free article] [PubMed]
  • Ehrlich PR, White RR, Singer MC, McKechnie SW, Gilbert LE. Checkerspot butterflies: a historical perspective. Science. 1975 Apr 18;188(4185):221–228. [PubMed]
  • Felsenstein J. The theoretical population genetics of variable selection and migration. Annu Rev Genet. 1976;10:253–280. [PubMed]
  • Koehn RK, Newell RI, Immermann F. Maintenance of an aminopeptidase allele frequency cline by natural selection. Proc Natl Acad Sci U S A. 1980 Sep;77(9):5385–5389. [PMC free article] [PubMed]
  • Larson A, Wake DB, Yanev KP. Measuring gene flow among populations having high levels of genetic fragmentation. Genetics. 1984 Feb;106(2):293–308. [PMC free article] [PubMed]
  • Lewontin RC, Krakauer J. Distribution of gene frequency as a test of the theory of the selective neutrality of polymorphisms. Genetics. 1973 May;74(1):175–195. [PMC free article] [PubMed]
  • Mantel N. The detection of disease clustering and a generalized regression approach. Cancer Res. 1967 Feb;27(2):209–220. [PubMed]
  • Miller SA, Dykes DD, Polesky HF. A simple salting out procedure for extracting DNA from human nucleated cells. Nucleic Acids Res. 1988 Feb 11;16(3):1215–1215. [PMC free article] [PubMed]
  • Moller D. Genetic diversity in spawning cod along the Norwegian coast. Hereditas. 1968;60(1):1–32. [PubMed]
  • Nei M. F-statistics and analysis of gene diversity in subdivided populations. Ann Hum Genet. 1977 Oct;41(2):225–233. [PubMed]
  • Nei M, Maruyama T. Letters to the editors: Lewontin-Krakauer test for neutral genes. Genetics. 1975 Jun;80(2):395–395. [PMC free article] [PubMed]
  • Ota T. Statistical analyses of Drosophila and human protein polymorphisms. Proc Natl Acad Sci U S A. 1975 Aug;72(8):3194–3196. [PMC free article] [PubMed]
  • Ohta T. Role of very slightly deleterious mutations in molecular evolution and polymorphism. Theor Popul Biol. 1976 Dec;10(3):254–275. [PubMed]
  • Place AR, Powers DA. Genetic variation and relative catalytic efficiencies: lactate dehydrogenase B allozymes of Fundulus heteroclitus. Proc Natl Acad Sci U S A. 1979 May;76(5):2354–2358. [PMC free article] [PubMed]
  • Pogson GH, Zouros E. Allozyme and RFLP heterozygosities as correlates of growth rate in the scallop Placopecten magellanicus: a test of the associative overdominance hypothesis. Genetics. 1994 May;137(1):221–231. [PMC free article] [PubMed]
  • Robertson A. Letters to the editors: Remarks on the Lewontin-Krakauer test. Genetics. 1975 Jun;80(2):396–396. [PMC free article] [PubMed]
  • Tizard R, Cate RL, Ramachandran KL, Wysk M, Voyta JC, Murphy OJ, Bronstein I. Imaging of DNA sequences with chemiluminescence. Proc Natl Acad Sci U S A. 1990 Jun;87(12):4514–4518. [PMC free article] [PubMed]
  • Vigue CL, Johnson FM. Isozyme variability in species of the genus Drosophila. VI. Frequency-property-environment relationships of allelic alcohol dehydrogenases in D. melanogaster. Biochem Genet. 1973 Jul;9(3):213–227. [PubMed]
  • Watt WB. Adaptation at specific loci. I. Natural selection on phosphoglucose isomerase of Colias butterflies: Biochemical and population aspects. Genetics. 1977 Sep;87(1):177–194. [PMC free article] [PubMed]
  • Workman PL, Niswander JD. Population studies on southwestern Indian tribes. II. Local genetic differentiation in the Papago. Am J Hum Genet. 1970 Jan;22(1):24–49. [PMC free article] [PubMed]
  • Wright S. Isolation by Distance. Genetics. 1943 Mar;28(2):114–138. [PMC free article] [PubMed]

Articles from Genetics are provided here courtesy of Genetics Society of America

Formats:

Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...

Links

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...