The estimation of Wright's fixation index from genotypic frequencies

Brown, A. H. D.

doi:10.1007/bf00958921

Cited by 131 publications

(61 citation statements)

References 3 publications

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“…Therefore counts were analyzed with nonparametric statistical tests. Genotypic frequencies were tested for fit to Hardy-Weinberg expectations (t), using t = F( IN), F being the inbreeding coefficient and N the sample size (Brown, 1970). Allele frequency differences between populations were tested for homogeneity using replicated G-test (likelihood-ratio test, Sokal and Rohlf, 1981).…”

Section: Methodsmentioning

confidence: 99%

Analysis of Meristic Characters and Genetic Differentiation in Greenland Halibut (Reinhardtius hippoglossoides) in the Northwest Atlantic

Rigét¹,

Boje²,

Simonsen³

1992

J. Northw. Atl. Fish. Sci.

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A stock identification study of Greenland halibut (Reinhardtius hippoglossoides) in the Northwest Atlantic was carried out based on samples from off eastern Newfoundland, Davis Strait, three West Greenland fjords and Denmark Strait. Meristic characters and frequencies of electrophoretically detectable alleles of protein loci were analyzed.Mean number of vertebrae showed significant heterogeneity among areas, while fin-ray numbers showed no difference. Offshore areas were very alike in terms of mean numbers of vertebrae, while those from the inshore areas of West Greenland differed both among themselves and from those of the offshore areas.The genetic variation between samples was small. In all samples the phenotypic distribution of four polymorphic loci was in accordance with the expectation from the Hardy-Weinberg proportions. Pair comparisons of the allelic distributions between samples showed that more than one breeding stock must exist.Although the Denmark Strait stock could not be separated from the stock in the area between West Greenland and Canada, results support the conclusion that at least two spawning stocks exist in the Northwest Atlantic. Results are consistent with the prevailing theory that Greenland halibut form a single, interbreeding stock in the offshore area between Canada and West Greenland, but also agree with other evidence that Greenland halibut in West Greenland fjords are partially isolated from the offshore stock.

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Section: Methodsmentioning

confidence: 99%

Analysis of Meristic Characters and Genetic Differentiation in Greenland Halibut (Reinhardtius hippoglossoides) in the Northwest Atlantic

Rigét¹,

Boje²,

Simonsen³

1992

J. Northw. Atl. Fish. Sci.

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“…Positive and negative values of Frs indicate excess and deficit of homozygotes. The significance of FIs was tested by calculating X 2 as F)s2 N, where N is sample size (Li 1955, Brown 1970). Inter-sample heterogeneity in allele frequencies was tested by contingency table analyses.…”

Section: Methodsmentioning

confidence: 99%

Genetic differentiation of the Iceland scallop Chlamys islandica (Pectinidae) in the northern Atlantic Ocean

Fevolden¹

1989

Mar. Ecol. Prog. Ser.

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Allozymic variation at gene loci encoding for glucosephosphate isomerase, phosphoglucomutase and superoxide dismutase was investigated In populations of Chlarnys islandica from waters around Jan Mayen, Spitsbergen, Bear Island and northern Norway. The Gpi locus was particularly polymorphic with at least 12 different alleles and a mean heterozygosity of 84 % Half the individuals were heterozygous at Pgm-2 and between 30 and 40 % at Sod. The high polymorphism at Gpi runs counter to an earlier hypothesis suggesting a positive correlation between environmental variability and Gpi polymorphism of pectinids. Pgm-2 and Sod revealed significant allele frequency heterogeneity among the different areas, Gpi only when the effective number of alleles was considered. The species has a large dispersal potential during a long planktonic larval stage, but information on the surface current system in the North Atlant~c suggests that restr~cted gene flow, with possible contributions from selective constraints, account for the observed pattern in gene variability. It is suggested that the conservative approach of managing each area as if it contained discrete genetic units of the species should be adopted.

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“…Existing simulations have found that at least low rates of selfing affect Moran's I only to the extent that male gamete dispersal distances are reduced, that is, through reductions in the neighborhood size. However, if the allele-specific maximum likelihood estimator of the fixation index (Brown, 1970)…”

Section: Other Measuresmentioning

confidence: 99%

Estimating dispersal from short distance spatial autocorrelation

2005

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A series of theoretical studies has formed a strong connection between spatial statistics observed in populations and summary measures of the amount of dispersal. Synthesized, these developments allow dispersal to be indirectly estimated from standing spatial patterns of genetic variation under a range of conditions broad enough to be likely met in most populations of either plants or animals. The spatial correlations at the shortest distances are particularly robust to range of conditions and have disproportionately high statistical power. This review integrates theoretical results in a way that maximizes robustness and flexibility in the use of short distance autocorrelation to estimate Wright's neighborhood size, or the total variance in dispersal distances. Empirical guidelines are developed that are meant to be as practical and broad as possible. The guidelines focus on Moran's I-statistics for diploid genotypes converted to allele frequencies, but are also extended to or compared with several other approaches. Heredity (2005) 95, 7-15.

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The estimation of Wright's fixation index from genotypic frequencies

Cited by 131 publications

References 3 publications

Analysis of Meristic Characters and Genetic Differentiation in Greenland Halibut (Reinhardtius hippoglossoides) in the Northwest Atlantic

Analysis of Meristic Characters and Genetic Differentiation in Greenland Halibut (Reinhardtius hippoglossoides) in the Northwest Atlantic

Genetic differentiation of the Iceland scallop Chlamys islandica (Pectinidae) in the northern Atlantic Ocean

Estimating dispersal from short distance spatial autocorrelation

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