Identification of General Patterns of Sex-Biased Expression in Daphnia, a Genus with Environmental Sex Determination
|Author(s)||Molinier Cecile1, Reisser Celine1, 2, 3, Fields Peter4, Segard Adeline1, Galimov Yan5, Haag Christoph R.1, 2|
|Affiliation(s)||1 : Univ Paul Valery Montpellier, Univ Montpellier, CNRS, EPHE,CEFE,Unite Mixte Rech 5175, 1919 Route Mende, F-34293 Montpellier 5, France.
2 : Univ Fribourg, Ecol & Evolut, Ch Musee 10, CH-1700 Fribourg, Switzerland.
3 : IFREMER, Ctr Pacifique, UMR EIO 241, Labex CORAIL, BP 49, Tahiti, Polynesie Franc, France.
4 : Univ Basel, Zool Inst, Evolutionary Biol, CH-4051 Basel, Switzerland.
5 : RAS, Koltsov Inst Dev Biol, Ul Vavilova 26, Moscow 119334, Russia.
|Source||G3-genes Genomes Genetics (2160-1836) (Genetics Society America), 2018-05 , Vol. 8 , N. 5 , P. 1523-1533|
|WOS© Times Cited||4|
|Keyword(s)||Differential gene expression, males, females, Daphnia, ESD, Genetics of Sex|
Daphnia reproduce by cyclic-parthenogenesis, where phases of asexual reproduction are intermitted by sexual production of diapause stages. This life cycle, together with environmental sex determination, allow the comparison of gene expression between genetically identical males and females. We investigated gene expression differences between males and females in four genotypes of Daphnia magna and compared the results with published data on sex-biased gene expression in two other Daphnia species, each representing one of the major phylogenetic clades within the genus. We found that 42% of all annotated genes showed sex-biased expression in D. magna. This proportion is similar both to estimates from other Daphnia species as well as from species with genetic sex determination, suggesting that sex-biased expression is not reduced under environmental sex determination. Among 7453 single copy, one-to-one orthologs in the three Daphnia species, 707 consistently showed sex-biased expression and 675 were biased in the same direction in all three species. Hence these genes represent a core-set of genes with consistent sex-differential expression in the genus. A functional analysis identified that several of them are involved in known sex determination pathways. Moreover, 75% were overexpressed in females rather than males, a pattern that appears to be a general feature of sex-biased gene expression in Daphnia.