# Statistical genetics

Term: Statistical Genetics (also known as Population Genetics)

Description: Statistical Genetics involves the identification of genetic variation to help us understand why certain people are more prone to mental and physical illness. The variations in genes are due to natural selection, genetic drift, mutation,and gene flow. Statistical genetics(population genetics) came about in the 1920's and 1930's because of a few mathematicians by the names of R.A. Fisher, J.B.S. Haldane, and Sewall Wright. The models they developed explore how evolutionary processes modify genetic composition. They opened a door to explore new ways to look at evolution quantitatively rather than qualitatively. Studying genetics led to the development of the Human Genome Project where the entire human genome has been recorded and can be used to make predictions one if someone is predisposed to a condition due to historical data based on their genes. Using statistical genetics, patterns can be recorded in order to better explain causes and correlations between genes and diseases. This can lead to earlier diagnoses of diseases and can be used as preventative measures in the future.

Applications: Statistical genetics studies allele frequency, which is the proportion of all copies of a gene in the gene pool. A gene pool is the complete set of alleles for a given species. For example, in a moth gene pool there two alleles: black and white. The allele frequency is studied within a given population and two different populations of the same species can have a huge difference in allele frequency. The relative change in frequency of alleles is called genetic drift. Genetic drift is due to random sampling and over time can cause gene variants to disappear completely. Mutation are changes in the DNA sequence of a cell caused by radiation, viruses, mutagenic chemicals, and problems that arise during meiosis. The exchanging of genes within a species from different populations is known as gene flow. This occurs from migration and breeding and can be limited by mobility.

Web Resources:

Related Terminology:
Population Genetics
Darwinism
Evolution

Citations/References:
Beurton, P.J., Falk, R. and Rheinberger, H., (eds.), 2000, The Concept of the Gene in Development and Evolution, Cambridge: Cambridge University Press.
Hartl, Daniel (2007). Principles of Population Genetics//. Sinauer Associates. p. 95. ISBN 978-0-87893-308-2.