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Drift is often subdivided into unstratified (unsorted) drift (glacial till) that forms moraines and stratified drift (glaciolacustrine and fluvioglacial sediments) that accumulates as stratified and sorted sediments in the form of outwash plains, eskers, kames, varves, and so forth. The term drift clay is a synonym for boulder clay. Both are ...
Environmental heterogeneity has historically been identified as a vital source of genetic variations and distinctions due to isolation, and several studies have found correlations between neutral genetic differences, ecological heterogeneity, and genetic isolation. The genetic isolation and different associations in regional heterogeneity could ...
Allelic heterogeneity is the phenomenon in which different mutations at the same locus lead to the same or very similar phenotypes. These allelic variations can arise as a result of natural selection processes, as a result of exogenous mutagens , genetic drift , or genetic migration .
There is a critical difference between deletion and CN-LOH, as the latter mechanism cannot be detected by comparative genomic hybridization (CGH)-based gene copy number counting, and requires allelic genotyping. Either way, LOH leaves only non-functioning alleles of the TSG, and the individual may go on to develop cancer.
Fixation rates can easily be modeled as well to see how long it takes for a gene to become fixed with varying population sizes and generations. For example, The Biology Project Genetic Drift Simulation allows to model genetic drift and see how quickly the gene for worm color goes to fixation in terms of generations for different population sizes.
Tajima's D is a population genetic test statistic created by and named after the Japanese researcher Fumio Tajima. [1] Tajima's D is computed as the difference between two measures of genetic diversity: the mean number of pairwise differences and the number of segregating sites, each scaled so that they are expected to be the same in a neutrally evolving population of constant size.
Genetic heterogeneity occurs through the production of single or similar phenotypes through different genetic mechanisms. There are two types of genetic heterogeneity: allelic heterogeneity, which occurs when a similar phenotype is produced by different alleles within the same gene; and locus heterogeneity, which occurs when a similar phenotype is produced by mutations at different loci.
The spatial stratified heterogeneity categorises the geographic phenomena whose the within-strata variance of its attributes' values is significantly lower than its between-strata variance, such as collections of ecological zones or land-use classes within a given geographic area depict.