population genetics Population genetics is a subfield of genetics that deals with genetic differences within and between populations, and is a part of evolutionary biology. Studies in this branch of biology examine such phenomena as adaptation, speciation, and pop ...

, cryptic relatedness occurs when individuals in a

genetic association Genetic association is when one or more genotypes within a population co-occur with a phenotypic trait more often than would be expected by chance occurrence. Studies of genetic association aim to test whether single-locus alleles or genotype fre ...

study are more closely related to another population than assumed by the investigators. This can act as a confounding factor in both case-control and genome-wide association studies, as well as in studies of

genetic diversity Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species, it ranges widely from the number of species to differences within species and can be attributed to the span of survival for a species. It is dis ...

. Along with population stratification, it is one of the most prominent confounding factors that can lead to inflated false positive rates in gene-association studies. It is often corrected for by including a polygenic component in the

statistical model A statistical model is a mathematical model that embodies a set of statistical assumptions concerning the generation of Sample (statistics), sample data (and similar data from a larger Statistical population, population). A statistical model repres ...

being used to detect genetic associations. Other approaches that have been developed to attempt to control for cryptic relatedness are the

genomic control Genomic control (GC) is a statistical method that is used to control for the confounding effects of population stratification in genetic association studies. The method was originally outlined by Bernie Devlin and Kathryn Roeder in a 1999 paper. ...

method and the use of extended

likelihood ratio test In statistics, the likelihood-ratio test assesses the goodness of fit of two competing statistical models based on the ratio of their likelihoods, specifically one found by maximization over the entire parameter space and another found after im ...

References

Statistical genetics Population genetics Medical genetics {{Genetics-stub