Kato Yasuhiko, Kobayashi Kaoru, Oda Shigeto, Colbourn John K, Tatarazako Norihisa, Watanabe Hajime, Iguchi Taisen
Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, 5-1 Higashiyama, Okazaki, Aichi 444-8787, Japan.
Genomics. 2008 Jan;91(1):94-101. doi: 10.1016/j.ygeno.2007.09.002. Epub 2007 Nov 26.
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.
众所周知，大型溞会根据环境在有性生殖和无性生殖之间切换。当处于食物、光周期和种群密度的最佳环境中时，它会进行无性生殖。一旦环境恶化，它就会将生殖策略从无性生殖转变为有性生殖。然而，环境性别决定的分子基础在很大程度上尚不清楚。为了了解大型溞环境性别决定的分子机制，分离与性别决定相关的基因至关重要。由于DM结构域基因是众所周知的与性别相关的基因，我们旨在从大型溞中鉴定DM结构域基因。基于使用大型溞cDNA对保守DM结构域进行简并PCR，我们鉴定出了三个与黑腹果蝇的DMRT11E、DMRT93B和DMRT99B相对应的DM结构域基因。性腺中的定量基因表达分析表明，DMRT93B仅在睾丸中表达。这一发现有助于更好地理解根据环境从无性生命周期向有性生命周期的转换机制。
