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Equation 2 · Part 6 · From Origins to Frontier: A History of Evolutionary Biology and Ecology

change

Var⁡(Δp)=p(1−p)2Ne,\operatorname{Var}(\Delta p) = \frac{p(1-p)}{2N_e},
change

What this part means

Capital delta attached to a quantity marks a difference between two values of that quantity; the article’s sign convention determines the order.

Its job in the formula

Capital delta attached to a quantity marks a difference between two values of that quantity; the article’s sign convention determines the order.

The passage around this formula

Sewall Wright’s 1931 paper, “Evolution in Mendelian Populations,” added the piece Fisher’s and Haldane’s more deterministic treatments lacked: a formal account of genetic drift, the random change in allele frequency from generation to generation caused by finite population size [ 3 ] . Wright showed that in a randomly mating population of effective size NeN_e , the variance in allele frequency change per generation from sampling alone is Var⁡(Δp)=p(1−p)2Ne\operatorname{Var}(\Delta p) = \frac{p(1-p)}{2N_e}. for a diploid population starting at allele frequency p . This single expression carries a real consequence: small populations can fix or lose alleles by chance alone, independent of whether those alleles are beneficial, neutral, or mildly…

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Learn the underlying idea

Addition combines quantities; subtraction measures the signed difference between them. Parentheses show what is combined before the rest of the expression is evaluated.

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Sources cited in the surrounding passage

These citations provide research context; check each source for the exact claim it supports.