Multigenerational response to artificial selection for biased clutch sex ratios in Tigriopus californicus populations

• Published in: Journal of evolutionary biology Vol. 27; no. 9; pp. 1921 - 1929
• Main Authors: Alexander, H. J, Richardson, J. M. L, Anholt, B. R
• Format: Journal Article
• Language: English
• Published: Switzerland Blackwell Science 01-09-2014; Blackwell Publishing Ltd
• Subjects: Animals; artificial selection; Biological Evolution; Copepoda; Copepoda - physiology; Crustaceans; Evolutionary biology; Female; Genetics, Population; heritability; Inbreeding; Male; maternal effect; polygenic sex determination; realized heritability; selection response; Selection, Genetic; sex determination; Sex Determination Processes; Sex Ratio; Tigriopus californicus; variance; Tigriopus californicus; sex ratio; realized heritability; artificial selection; polygenic sex determination
• ISSN: 1010-061X; 1420-9101
• DOI: 10.1111/jeb.12449

Polygenic sex determination (PSD) is relatively rare and theoretically evolutionary unstable, yet has been reported across a range of taxa. Evidence for multilocus PSD is provided by (i) large between‐family variance in sex ratio, (ii) paternal and maternal effects on family sex ratio and (iii) response to selection for family sex ratio. This study tests the polygenic hypothesis of sex determination in the harpacticoid copepod Tigriopus californicus using the criterion of response to selection. We report the first multigenerational quantitative evidence that clutch sex ratio responds to artificial selection in both directions (selection for male‐ and female‐biased families) and in multiple populations of T. californicus. In the five of six lines that showed a response to selection, realized heritability estimated by multigenerational analysis ranged from 0.24 to 0.58. Divergence of clutch sex ratio between selection lines is rapid, with response to selection detectable within the first four generations of selection.