Data from: Inbreeding ratio and genetic relationships among strains of the Western clawed frog, Xenopus tropicalis

The Western clawed frog, Xenopus tropicalis, is a highly promising model amphibian, especially in developmental and physiological research, and as a tool for understanding disease. It was originally found in the West African rainforest belt, and was introduced to the research community in the 1990s. The major strains thus far known include the Nigerian and Ivory Coast strains. However, due to its short history as an experimental animal, the genetic relationship among the various strains has not yet been clarified, and establishment of inbred strains has not yet been achieved. Since 2003 the Institute for Amphibian Biology (IAB), Hiroshima University has maintained stocks of multiple X. tropicalis strains and conducted consecutive breeding as part of the National BioResource Project. In the present study we investigated the inbreeding ratio and genetic relationship of four inbred strains at IAB, as well as stocks from other institutions, using highly polymorphic microsatellite markers and mitochondrial haplotypes. Our results show successive reduction of heterozygosity in the genome of the IAB inbred strains. The Ivory Coast strains clearly differed from the Nigerian strains genetically, and three subgroups were identified within both the Nigerian and Ivory Coast strains. It is noteworthy that the Ivory Coast strains have an evolutionary divergent genetic background. Our results serve as a guide for the most effective use of X. tropicalis strains, and the long-term maintenance of multiple strains will contribute to further research efforts.

西部爪蟾（Xenopus tropicalis）是极具应用潜力的模式两栖动物，在发育生物学与生理学研究以及疾病机制解析中均展现出重要的工具价值。该物种最初发现于西非雨林带，并于20世纪90年代被引入科研社群。目前已知的主要品系包括尼日利亚品系与科特迪瓦品系。然而，由于其作为实验动物的研究历史较短，不同品系间的遗传关系尚未阐明，近交品系的构建也尚未完成。自2003年起，广岛大学两栖动物生物学研究所（IAB）作为国家生物资源计划的组成部分，保藏了多株热带爪蟾品系并开展连续繁育工作。本研究利用多态性丰富的微卫星标记与线粒体单倍型，对该研究所保藏的4个近交品系以及其他机构的保藏种群的近交系数与遗传关系进行了分析。结果显示，广岛大学保藏的近交品系基因组杂合度呈持续降低趋势。科特迪瓦品系与尼日利亚品系在遗传层面存在显著分化，且两类品系内部均各鉴定出3个亚组。值得注意的是，科特迪瓦品系具有进化上独立分化的遗传背景。本研究结果可为热带爪蟾品系的高效利用提供参考依据，而多品系的长期保藏也将为后续相关研究提供有力支撑。