Secondary Theorem of Natural Selection in biocultural populations

• Published in: Theoretical population biology Vol. 41; no. 1; pp. 72 - 89
• Main Author: Findlay, C.Scott
• Format: Journal Article
• Language: English
• Published: Meppel Elsevier Inc 01.02.1992; Elsevier
• Subjects: Biological and medical sciences; Biological Evolution; Culture; Fundamental and applied biological sciences. Psychology; Genetics of eukaryotes. Biological and molecular evolution; Humans; inheritance; man; Mathematics; Models, Biological; natural selection; Population genetics, reproduction patterns; Selection, Genetic; Theories and miscellaneous; Time Factors; transmission; Theory; Inheritance; Genetic character; Cultural aspect; Mathematical model; Population genetics; Fitness; Natural selection
• ISSN: 0040-5809; 1096-0325
• DOI: 10.1016/0040-5809(92)90050-4

The “Secondary Theorem of Natural Selection,” an extension of Fisher's fundamental theorem, states that the rate of change in the mean of an arbitrary character in response to selection is proportional to the additive genetic covariance between the character and fitness. Here I derive an expression for the change in the mean value of a trait subject to both genetic and cultural transmission. I start with the one-locus case under generalized mating and cultural transmission from parents to offspring, then proceed to the two-locus case. My results support previous work on the effects of nongenetic inheritance by showing that (i) cultural transmission introduces a timelag in the population response to selection; (ii) with cultural transmission the effects of selection persist even after selection is relaxed; and (iii) cultural transmission can either enhance or retard phenotypic evolution relative to that obtained under purely genetic transmission.