Redbelly Dace Case Study

The founder effect offers a potential explanation for the significantly higher observed heterozygosity of the Collins Creek over the pond Redbelly Dace populations. The migration of the fish to the isolated pond could have been accomplished through an anomalous transport of eggs on waterfowl or other animals travelling between the two water bodies; the small group of migrants would in turn be genetically unrepresentative of the original creek population. The disequilibrium of the Hardy-Weinberg proportions, generalized as (p1 + … + pn)2 =1, pn representing the allele frequency if a particular locus is polymorphic (as in the case of microsatellites), indicates the presence of an evolutionary force influencing the decrease in the frequency of heterozygosity of the pond population. The founder effect would result in disequilibrium …show more content…
The clastogenic properties of certain pesticides could lead to the damage of the fish DNA and result in decreased values of genetic diversity. The absence of the sixth microsatellite in the pond population further indicates a DNA damaging agent could be related to the disparity in the observed heterozygosity. A study on Mytilus galloprovincialis collected from 10 Turkish and Greek coast sites showed a decline in heterozygosity and effective allele number in populations heavily polluted by chemical contaminants (Giantsis et al. 2012). Genetic diversity may have been decreased through the selection of more tolerant genotypes to chromosomal aberrations; the elimination of sensitive genotypes then alters the genetic structure of the population. This effect on genetic diversity can be compounded by bottleneck effects from toxicity related deaths that cause disequilibria in terms of allele frequencies from the lack of allelic representation in the reduced