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The level of gene flow among populations can be estimated by observing the dispersal of individuals and recording their reproductive success. [4] [11] This direct method is only suitable for some types of organisms, more often indirect methods are used that infer gene flow by comparing allele frequencies among population samples.
Chromosomal crossover, or crossing over, is the exchange of genetic material during sexual reproduction between two homologous chromosomes' non-sister chromatids that results in recombinant chromosomes. It is one of the final phases of genetic recombination, which occurs in the pachytene stage of prophase I of meiosis during a process called ...
Phenotypic variation (due to underlying heritable genetic variation) is a fundamental prerequisite for evolution by natural selection. It is the living organism as a whole that contributes (or not) to the next generation, so natural selection affects the genetic structure of a population indirectly via the contribution of phenotypes.
In analyzing VNTR data, two basic genetic principles can be used: Identity Matching – both VNTR alleles from a specific location must match. If two samples are from the same individual, they must show the same allele pattern. Inheritance Matching – the VNTR alleles must follow the rules of inheritance. In matching an individual with his ...
Population structure (also called genetic structure and population stratification) is the presence of a systematic difference in allele frequencies between subpopulations. In a randomly mating (or panmictic ) population, allele frequencies are expected to be roughly similar between groups.
In biology, polymorphism [1] is the occurrence of two or more clearly different morphs or forms, also referred to as alternative phenotypes, in the population of a species. To be classified as such, morphs must occupy the same habitat at the same time and belong to a panmictic population (one with random mating).
V P = V E + V G, where the terms refer to variation in phenotype, environment, and genotype respectively. [1] Broad sense heritability (H 2, or H B) refers to the phenotypic differences arising from all genetic effects, and can be described as the ratio of genotypic variation to that of phenotypic variation in the population, or: H 2 = V G / V P.
The word "allele" is a short form of "allelomorph" ("other form", a word coined by British geneticists William Bateson and Edith Rebecca Saunders) in the 1900s, [7] [8] which was used in the early days of genetics to describe variant forms of a gene detected in different phenotypes and identified to cause the differences between them.