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Non‐canonical expression patterns and evolutionary rates of sex‐biased genes in a seasonal fish
Author(s) -
Machado Miguel P.,
Matos Isa,
Grosso Ana R.,
Schartl Manfred,
Coelho Maria M.
Publication year - 2016
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.22752
Subject(s) - biology , transcriptome , gonad , aromatase , sexual differentiation , gene , evolutionary biology , development of the gonads , genetics , zoology , gene expression , endocrinology , cancer , breast cancer
SUMMARY Sex determination is a highly variable process that utilizes many different mechanisms to initiate the cascade of differentiation processes. The molecular pathways controlling sexual development are less conserved than previously assumed, and appear to require active maintenance in some species; indeed, the developmental decision of gonad phenotype in gonochoristic species is not fixed at an early developmental stage. Much of the knowledge about sex determination mechanisms was derived from research on gonochoristic, non‐seasonal breeders. In this study, the transcriptome of resting adult gonads of a seasonal breeder, the endangered Iberian cyprinid fish Squalius pyrenaicus , was analyzed to assess the expression patterns and evolutionary rates of sex‐biased genes that could be involved in maintenance of gonad identity as well as in sex determination. Remarkably, some crucial female genes—such as aromatase cyp19a1a , estrogen receptor esr1a , and foxl2 —were expressed more abundantly in S. pyrenaicus testis than in ovaries. Moreover, contrary to the higher evolutionary rate changes observed in male‐biased genes, higher d N / d S ratios were observed for female‐biased genes than for male‐biased genes in S. pyrenaicus . These results help unravel the impact of seasonality in sex determination mechanisms and the evolution of genes, and highlight the need to study fish at different gonadal maturation states to understand the function of sex‐biased genes. Mol. Reprod. Dev. 83: 1102–1115, 2016. © 2016 Wiley Periodicals, Inc .