%0 Journal Article %1 hedgecock1978population %A Hedgecock, Dennis %D 1978 %I Society for the Study of Evolution, Wiley %J Evolution %K home_range isolation_by_distance newts population_density %N 2 %P 271--286 %T Population Subdivision and Genetic Divergence in the Red-Bellied Newt, Taricha rivularis %U http://www.jstor.org/stable/2407595 %V 32 %X An attempt is made to synthesize information on the population ecology and genetics of the salamander Taricha rivularis. Published and unpublished data gathered by V. C. Twitty and co-workers during extensive field studies in Sonoma Co., California, are reviewed and summarized. Two generalizations with respect to the population structure of T. rivularis emerge: 1) deme sizes may be as much as 103 or 104, and 2) homing behavior during breeding migration restricts gene flow within and especially between streams. 'Neighbor-hood' size of a deme is estimated to be about one kilometer. Six population samples from each of two drainage systems are assayed by means of starch gel electrophoresis for variation in up to 40 loci. On the average 20.9% ± 1.0% of the loci in any one population sample are polymorphic, there are 1.24 ± 0.01 alleles per locus, and the proportion of loci heterozygous per individual is 6.8% ± 0.2%. While nearly all of the individual phenotypic distributions within populations agree with random mating expectations, a consistent and significant deficiency of heterozygotes across all loci is apparent. This may be due to pooling of individuals from different demes (Wahlund effect). Genetic similarity is greater within drainages (I = 0.997 ± 0.0003) than between drainages (I = 0.989 ± 0.001) as expected. Eight polymorphic loci show uniform, variable and clinal geographic patterns in allele frequencies as well as some striking differences between adjacent population samples. An expectation for the amount of random-drift gene frequency divergence among populations of a drainage system is taken from Sewall Wright's model of a continuous, linearly distributed population. Standardized allele frequency variances for the two drainages, FST = 0.024 ± 0.005 and 0.029 ± 0.005, agree fairly well with this expectation. Nevertheless, geographic patterns and discontinuities and convergences in allele frequencies require further explanation. Several possible alternative hypotheses to account for the observations are subject to experimental falsification.

@article{hedgecock1978population, abstract = {An attempt is made to synthesize information on the population ecology and genetics of the salamander Taricha rivularis. Published and unpublished data gathered by V. C. Twitty and co-workers during extensive field studies in Sonoma Co., California, are reviewed and summarized. Two generalizations with respect to the population structure of T. rivularis emerge: 1) deme sizes may be as much as 103 or 104, and 2) homing behavior during breeding migration restricts gene flow within and especially between streams. 'Neighbor-hood' size of a deme is estimated to be about one kilometer. Six population samples from each of two drainage systems are assayed by means of starch gel electrophoresis for variation in up to 40 loci. On the average 20.9% ± 1.0% of the loci in any one population sample are polymorphic, there are 1.24 ± 0.01 alleles per locus, and the proportion of loci heterozygous per individual is 6.8% ± 0.2%. While nearly all of the individual phenotypic distributions within populations agree with random mating expectations, a consistent and significant deficiency of heterozygotes across all loci is apparent. This may be due to pooling of individuals from different demes (Wahlund effect). Genetic similarity is greater within drainages (I = 0.997 ± 0.0003) than between drainages (I = 0.989 ± 0.001) as expected. Eight polymorphic loci show uniform, variable and clinal geographic patterns in allele frequencies as well as some striking differences between adjacent population samples. An expectation for the amount of random-drift gene frequency divergence among populations of a drainage system is taken from Sewall Wright's model of a continuous, linearly distributed population. Standardized allele frequency variances for the two drainages, FST = 0.024 ± 0.005 and 0.029 ± 0.005, agree fairly well with this expectation. Nevertheless, geographic patterns and discontinuities and convergences in allele frequencies require further explanation. Several possible alternative hypotheses to account for the observations are subject to experimental falsification.}, added-at = {2024-07-04T16:20:58.000+0200}, author = {Hedgecock, Dennis}, biburl = {https://www.bibsonomy.org/bibtex/2ab052849b6a70a27c03f1cb3d3b06d58/peter.ralph}, interhash = {f6795e57bf1c0d8439963f12b62c133a}, intrahash = {ab052849b6a70a27c03f1cb3d3b06d58}, issn = {00143820, 15585646}, journal = {Evolution}, keywords = {home_range isolation_by_distance newts population_density}, number = 2, pages = {271--286}, publisher = {[Society for the Study of Evolution, Wiley]}, timestamp = {2024-07-04T16:20:58.000+0200}, title = {Population Subdivision and Genetic Divergence in the Red-Bellied Newt, \textit{{Taricha} rivularis}}, url = {http://www.jstor.org/stable/2407595}, volume = 32, year = 1978 }