2017年6月
Sex chromosome differentiation and the W- and Z-specific loci in Xenopus laevis
DEVELOPMENTAL BIOLOGY
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- 巻
- 426
- 号
- 2
- 開始ページ
- 393
- 終了ページ
- 400
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1016/j.ydbio.2016.06.015
- 出版者・発行元
- ACADEMIC PRESS INC ELSEVIER SCIENCE
Genetic sex-determining systems in vertebrates include two basic types of heterogamety; XX (female)/ XY (male) and ZZ (male)/ZW (female) types. The African clawed frog Xenopus laevis has a ZZ/ZW-type sex-determining system. In this species, we previously identified a W-specific sex (female)-determining gene dmw, and specified W and Z chromosomes, which could be morphologically indistinguishable (homomorphic). In addition to dmw, we most recently discovered two genes, named scanw and ccdc69w, and one gene, named capn5z in the W-and Z-specific regions, respectively. In this study, we revealed the detail structures of the W/Z-specific loci and genes. Sequence analysis indicated that there is almost no sequence similarity between 278 kb W-specific and 83 kb Z-specific sequences on chromosome 2Lq3233, where both the transposable elements are abundant. Synteny and phylogenic analyses indicated that all the W/Z-specific genes might have emerged independently. Expression analysis demonstrated that scanw and ccdc69w or capn5z are expressed in early differentiating ZW gonads or testes, thereby suggesting possible roles in female or male development, respectively. Importantly, the sex-determining gene (SDG) dmw might have been generated after allotetraploidization, thereby indicating the construction of the new sex-determining system by dmw after species hybridization. Furthermore, by direct genotyping, we confirmed that diploid WW embryos developed into normal female frogs, which indicate that the Z-specific region is not essential for female development. Overall, these findings indicate that sex chromosome differentiation has started, although no heteromorphic sex chromosomes are evident yet, in X laevis. Homologous recombination suppression might have promoted the accumulation of mutations and transposable elements, and enlarged the W/Z-specific regions, thereby resulting in differentiation of the W/Z chromosomes. (C) 2016 Elsevier Inc. All rights reserved.
- リンク情報
- ID情報
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- DOI : 10.1016/j.ydbio.2016.06.015
- ISSN : 0012-1606
- eISSN : 1095-564X
- PubMed ID : 27297884
- Web of Science ID : WOS:000404064800023