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Genetic map function. In genetics, mapping functions are used to model the relationship between map distance (measured in map units or centimorgans) between markers and recombination frequency between markers. One utility of this is that it allows values to be obtained for genetic distances, which is typically not estimable, from recombination ...
Figure 1: Genetic distance map by Cavalli-Sforza et al. (1994) [1] Genetic distance is a measure of the genetic divergence between species or between populations within a species, whether the distance measures time from common ancestor or degree of differentiation. [2] Populations with many similar alleles have small genetic distances.
Centimorgan. In genetics, a centimorgan (abbreviated cM) or map unit ( m.u.) is a unit for measuring genetic linkage. It is defined as the distance between chromosome positions (also termed loci or markers) for which the expected average number of intervening chromosomal crossovers in a single generation is 0.01.
The fixation index ( FST) is a measure of population differentiation due to genetic structure. It is frequently estimated from genetic polymorphism data, such as single-nucleotide polymorphisms (SNP) or microsatellites. Developed as a special case of Wright's F-statistics, it is one of the most commonly used statistics in population genetics.
There are two distinctive mapping approaches used in the field of genome mapping: genetic maps (also known as linkage maps) [7] and physical maps. [3] While both maps are a collection of genetic markers and gene loci, [8] genetic maps' distances are based on the genetic linkage information, while physical maps use actual physical distances usually measured in number of base pairs.
Simple genetic distance calculations will thus undercount the number of mutation events that have occurred in evolutionary history. The extent of this undercount increases with increasing time since divergence, which can lead to the phenomenon of long branch attraction , or the misassignment of two distantly related but convergently evolving ...
Linkage disequilibrium. In population genetics, linkage disequilibrium ( LD) is a measure of non-random association between segments of DNA ( alleles) at different positions on the chromosome ( loci) in a given population based on a comparison between the frequency at which two alleles are detected together at the same loci and the frequencies ...
Genotype–phenotype distinction. Similar genotypic changes may result in similar phenotypic alterations, even across a wide range of species. [1] The genotype–phenotype distinction is drawn in genetics. The "genotype" is an organism's full hereditary information. The "phenotype" is an organism's actual observed properties, such as morphology ...