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A genetic isolate is a population of organisms that has little to no genetic mixing with other organisms of the same species due to geographic isolation or other factors that prevent reproduction. Genetic isolates form new species through an evolutionary process known as speciation .
The patterns of isolation by distance as shown among human genetic data representing 346 microsatellite loci taken from 1484 individuals in 78 human populations. The horizontal axis of both charts is geographic distance as measured along likely routes of human migration.
Genetic hitchhiking is often considered the opposite of background selection. genetic load Any reduction in the mean fitness of a population owing to the existence of one or more genotypes with lower fitness than that of the most fit genotype. [1] genetic testing. Also DNA testing and genetic screening.
In addition to the genetic causes of reproductive isolation between species there is another factor that can cause post zygotic isolation: the presence of microorganisms in the cytoplasm of certain species. The presence of these organisms in a species and their absence in another causes the non-viability of the corresponding hybrid.
It has been said that "there is no universally accepted definition for the terms 'strain', 'variant', and 'isolate' in the virology community, and most virologists simply copy the usage of terms from others". [2] A strain is a genetic variant or subtype of a microorganism (e.g., a virus, bacterium or fungus).
The genetic information stored in DNA represents the genotype, whereas the phenotype results from the "interpretation" of that information. Such phenotypes are often displayed by the synthesis of proteins that control the organism's structure and development, or that act as enzymes catalyzing specific metabolic pathways.
Genetic divergence will always accompany reproductive isolation, either due to novel adaptations via selection and/or due to genetic drift, and is the principal mechanism underlying speciation. On a molecular genetics level, genetic divergence is due to changes in a small number of genes in a species, resulting in speciation . [ 2 ]
For example, leading cancer researchers comment on cancer, genetic counselors explain genetic testing terms, and expert gene hunters tackle the many terms surrounding the search for or mapping of genes. All speakers are actively working in the field, and most work at NHGRI. The written definition provides a reasonable definition for each term.