Implications of polygenic sex determination in an intertidal copepod

BMSC researchers Dr. Brad Anholt (UVIC), Dr. Jean Richardson, Dr. Heather Alexander, with the help of  many diligent assistants in the lab, counted 10’s of 1000’s of tiny marine intertidal copepod, Tigriopus californicus, in order to understand the sex-determining mechanism in this species.

In most animals, sex chromosomes determine the sex of offspring, and such a fixed genotype for sex has made theory difficult to test since genotypic variance for the trait (sex) is lacking. Previous publications have indicated that the marine copepod Tigriopus californicus has no sex chromosomes; and sex is determined by multiple genes affecting female brood sex ratio, and a brood sex ratio that responds to selection.

Further supportive evidence of polygenic sex determination was recently published in Ecology and Evolution:

Richardson, J.M.L., Alexander, H.J., and B.R. Anholt. 2022. Variance Components of Sex Determination in the copepod Tigriopus californicus estimated from a pedigree analysis. Ecology and Evolution. DOI: 10.22541/au.167162096.65025058/v1