Gene Frequency Estimation
- Measures how common a specific gene or genetic variant is within a population.
- Common estimation methods are: analyzing DNA samples with genetic markers and inferring frequencies from pedigree diagrams.
- Useful for understanding the distribution and evolution of genetic variation in a population.
Definition
Section titled “Definition”Gene frequency refers to the relative frequency of a specific gene or genetic variant within a population. This is typically expressed as a percentage or fraction, and it represents the proportion of individuals within a population that carry a particular gene or genetic variant.
Explanation
Section titled “Explanation”Gene frequency is a core concept in population genetics used to describe how often a particular genetic variant occurs among individuals in a population. Estimation can be performed directly by sampling DNA from individuals and identifying the presence or absence of a variant, or indirectly by using family relationship information to infer variant occurrence.
One direct approach uses a genetic marker, a specific DNA sequence that identifies a particular gene or variant. By analyzing DNA samples from a group of individuals, the number of individuals carrying the marker is counted and divided by the total sample size to compute the gene frequency.
An alternative approach is pedigree analysis, which leverages information about genetic relationships within families. By collecting family histories and constructing pedigree diagrams, one can analyze inheritance patterns to infer the frequency of a gene or variant in the broader population.
Examples
Section titled “Examples”Example 1 — Genetic marker and DNA sampling
Section titled “Example 1 — Genetic marker and DNA sampling”To estimate the frequency of a gene associated with a particular disease: collect a sample of DNA from a group of individuals; use a genetic marker to identify the presence or absence of the disease-associated gene in each individual; count the number of individuals who have the gene and divide by the total number of individuals in the sample to calculate the frequency.
Example 2 — Pedigree analysis
Section titled “Example 2 — Pedigree analysis”To estimate the frequency of a gene associated with an inherited disorder: collect information about family history of individuals within a population; construct a pedigree diagram; analyze the pedigree diagram to determine the frequency of the disorder-associated gene within the population.
Use cases
Section titled “Use cases”- Understanding the distribution and evolution of genetic variation within a population.
- Gaining insight into the genetic makeup of a population.
Related terms
Section titled “Related terms”- Genetic marker
- Pedigree analysis
- Population genetics