title: Molecular cloning and sexually dimorphic expression of DM-domain genes in Daphnia magna.
abstract: Daphnia magna is known to switch between sexual and asexual reproduction depending on the environment. It reproduces asexually when in an optimal environment for food, photoperiod, and population density. Once the environment declines, it changes reproductive strategy from asexual to sexual reproduction. However, the molecular bases of environmental sex determination are largely unknown. To understand the molecular mechanisms of environmental sex determination in Daphnia, it is essential to isolate the genes related to sex determination. As DM-domain genes are well known as sex-related genes, we aimed to identify DM-domain genes from Daphnia. Based on degenerate PCR of conserved DM domains using Daphnia cDNA, we identified three DM-domain genes that corresponded to DMRT11E, DMRT93B, and DMRT99B of Drosophila melanogaster. Quantitative gene expression analysis in gonads revealed that DMRT93B was expressed only in the testis. This finding contributes to an improved understanding of the switching mechanism from an asexual to a sexual life cycle depending on the environment.
authors.affiliation: Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, 5-1 Higashiyama, Okazaki, Aichi 444-8787, Japan.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Kato
authors.forename: Kaoru
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Shigeto
authors.initials: S
authors.lastname: Oda
authors.forename: John K
authors.initials: JK
authors.lastname: Colbourn
authors.forename: Norihisa
authors.initials: N
authors.lastname: Tatarazako
authors.forename: Hajime
authors.initials: H
authors.lastname: Watanabe
authors.forename: Taisen
authors.initials: T
authors.lastname: Iguchi
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D003621:Daphnia / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology*; D008297:Male; D017434:Protein Structure, Tertiary / Q000502:physiology; D012098:Reproduction / Q000502:physiology; D019849:Sex Determination Processes; D013737:Testis / Q000378:metabolism; D014157:Transcription Factors / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D004268:DNA-Binding Proteins; D014157:Transcription Factors