Editing Covariance (section)

=== In genetics and molecular biology ===
Covariance is an important measure in [[biology]]. Certain sequences of [[DNA]] are conserved more than others among species, and thus to study secondary and tertiary structures of [[protein]]s, or of [[RNA]] structures, sequences are compared in closely related species. If sequence changes are found or no changes at all are found in [[noncoding RNA]] (such as [[microRNA]]), sequences are found to be necessary for common structural motifs, such as an RNA loop. In genetics, covariance serves a basis for computation of Genetic Relationship Matrix (GRM) (aka kinship matrix), enabling inference on population structure from sample with no known close relatives as well as inference on estimation of heritability of complex traits.

In the theory of [[evolution]] and [[natural selection]], the [[price equation]] describes how a [[genetic trait]] changes in frequency over time. The equation uses a covariance between a trait and [[fitness (biology)|fitness]], to give a mathematical description of evolution and natural selection. It provides a way to understand the effects that gene transmission and natural selection have on the proportion of genes within each new generation of a population.<ref name="Price1970">{{cite journal |last1= Price | first1=George |year=1970 |title=Selection and covariance |journal=Nature |volume=227 |issue=5257 |pages=520–521 | doi=10.1038/227520a0 |pmid=5428476| bibcode=1970Natur.227..520P | s2cid=4264723 }}</ref><ref name="Harman2020">{{cite journal |last1= Harman |first1=Oren |year=2020 | title=When science mirrors life: on the origins of the Price equation |publisher=royalsocietypublishing.org |journal= Philosophical Transactions of the Royal Society B: Biological Sciences|volume=375 |issue=1797 |pages=1–7 | doi=10.1098/rstb.2019.0352 |pmid=32146891 |pmc=7133509 |doi-access=free }}</ref>