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Developmental sexual dimorphism and the evolution of mechanisms for adjustment of sex ratios in mammals


Cameron, EZ and Edwards, AM and Parsley, LM, Developmental sexual dimorphism and the evolution of mechanisms for adjustment of sex ratios in mammals, Annals of the New York Academy of Sciences, 1389 pp. 147-163. ISSN 0077-8923 (2016) [Refereed Article]

Copyright Statement

Copyright 2016 New York Academy of Sciences

DOI: doi:10.1111/nyas.13288


Sex allocation theory predicts biased offspring sex ratios in relation to local conditions if they would maximize parental lifetime reproductive return. In mammals, the extent of the birth sex bias is often unpredictable and inconsistent, leading some to question its evolutionary significance. For facultative adjustment of sex ratios to occur, males and females would need to be detectably different from an early developmental stage, but classic sexual dimorphism arises from hormonal influences after gonadal development. Recent advances in our understanding of early, pregonadal sexual dimorphism, however, indicate high levels of dimorphism in gene expression, caused by chromosomal rather than hormonal differences. Here, we discuss how such dimorphism would interact with and link previously hypothesized mechanisms for sex-ratio adjustment. These differences between males and females are sufficient for offspring sex both to be detectable to parents and to provide selectable cues for biasing sex ratios from the earliest stages. We suggest ways in which future research could use the advances in our understanding of sexually dimorphic developmental physiology to test the evolutionary significance of sex allocation in mammals. Such an approach would advance our understanding of sex allocation and could be applied to other taxa.

Item Details

Item Type:Refereed Article
Keywords:sex allocation, chromosomal sexual dimorphism, sex-linked traits, X-inactivation, extended evolutionary synthesis
Research Division:Biological Sciences
Research Group:Zoology
Research Field:Animal developmental and reproductive biology
Objective Division:Environmental Management
Objective Group:Management of Antarctic and Southern Ocean environments
Objective Field:Biodiversity in Antarctic and Southern Ocean environments
UTAS Author:Cameron, EZ (Professor Elissa Cameron)
UTAS Author:Edwards, AM (Dr Amy Edwards)
UTAS Author:Parsley, LM (Dr Laura Parsley)
ID Code:114825
Year Published:2016
Web of Science® Times Cited:7
Deposited By:Plant Science
Deposited On:2017-02-28
Last Modified:2017-10-31

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