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One can modify this definition and consider a grouping per sub-population instead of per individual. Population geneticists have used that idea to measure the degree of structure in a population. Unfortunately, there is a large number of definitions for , causing some confusion in the scientific literature. A common definition is the following:
Heterozygosity values of 51 worldwide human populations. [10] Sub-Saharan Africans have the highest values in the world. In population genetics, the concept of heterozygosity is commonly extended to refer to the population as a whole, i.e., the fraction of individuals in a population that are heterozygous for a particular locus. It can also ...
The remaining copy of the tumor suppressor gene can be inactivated by a point mutation or via other mechanisms, resulting in a loss of heterozygosity event, and leaving no tumor suppressor gene to protect the body. Loss of heterozygosity does not imply a homozygous state (which would require the presence of two identical alleles in the cell).
Heterozygosity is the fraction of individuals in a population that are heterozygous for a particular locus. Alleles per locus is also used to demonstrate variability. Nucleotide diversity is the extent of nucleotide polymorphisms within a population, and is commonly measured through molecular markers such as micro- and minisatellite sequences ...
When calculating an allele frequency for a diploid species, remember that homozygous individuals have two copies of an allele, whereas heterozygotes have only one. In our example, each of the 42 pink-flowered heterozygotes has one copy of the a allele, and each of the 9 white-flowered homozygotes has two copies.
In medical genetics, compound heterozygosity is the condition of having two or more heterogeneous recessive alleles at a particular locus that can cause genetic disease in a heterozygous state; that is, an organism is a compound heterozygote when it has two recessive alleles for the same gene, but with those two alleles being different from each other (for example, both alleles might be ...
Fst values between European populations. The fixation index (F ST) 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.
While heterozygosity at a given locus decreases over time as alleles become fixed or lost in the population, variation is maintained in the population through new mutations and gene flow due to migration between populations. For details, see population genetics.