FCA
Frequency correspondence analysis.

fecundity
The potential reproductive capacity of an individual or population (e.g., the number of eggs or young produced by an individual per unit time).

fertility
The ability to conceive and have offspring. Sometimes used for fecundity.

Fisher–Wright model
See Wright–Fisher model.

fitness
The ability of an individual, or genotype to survive and produce viable offspring. Quantified as the number of offspring contributed to the next generation, or as proportion of the individual’s genes in all the genes contributed to the next generation.

fitness rebound
Following an episode of inbreeding depression, successive generations of breeding may result in a rebound in fitness due to the selective decrease in frequency of deleterious alleles (purging). If inbreeding depression is due to deleterious recessive alleles (with negative fitness effects in a homozygous state) then successive generations of inbreeding may result in a rebound in fitness due to the selective decrease in frequency of deleterious alleles.

fixation index
The proportional increase of homozygosity through population subdivision. FST is sometimes referred to as the fixation index.

fluctuating asymmetry (FA)
Asymmetry in which deviations from symmetry are randomly distributed about a mean of zero. FA provides a simple measure of developmental precision or stability.

forensics
The use of scientific methods and techniques, such as genetic fingerprinting, to solve crimes.

founder effect
A loss of genetic variation in a population that was established by a small number of individuals that carry only a fraction of the original genetic diversity from a larger population. A special case of genetic drift.

frequency-dependent selection
Natural selection in which fitness varies as a function of the frequency of a phenotype.