Paternal inheritance of the primary sex ratio in a copepod.
Uniparentally inherited genetic elements are under strong selection to manipulate sex determination in their host and shift the host sex ratio towards the transmitting sex. For any sex-ratio trait, lineage analysis and quantitative genetics are important tools for characterizing the mode of inheritance (biparental vs. maternal vs. paternal) thereby narrowing the field of possible sex-determining mechanisms (e.g. polygenic, sex chromosomes with meiotic drive, cytoplasmic microorganisms). The primary sex ratio of the harpacticoid copepod, Tigriopus californicus is often male-biased and is highly variable among full sib families. We found that this extra-binomial variation for the primary sex ratio is paternally but not maternally transmitted in T. californicus. Paternal transmission of the primary sex ratio has been well documented in the haplo-diploid hymenoptera but is relatively rare in diplo-diploid organisms. If the sex-ratio trait is paternally transmitted in other closely related harpacticoid copepods it would explain why male biased primary sex ratios are so common in this group.
Voordouw
M J
MJ
Department of Biology, University of Victoria, Victoria, British Columbia, Canada. voordouw@uvic.ca
Robinson
H E
HE
Anholt
B R
BR
D000818:Animals; D033342:Copepoda / Q000235:genetics*; D003433:Crosses, Genetic; D005828:Genetics, Population; D040582:Inheritance Patterns / Q000235:genetics*; D008297:Male; D018401:Sample Size; D012744:Sex Ratio