Genetics of reproductive isolation and sex determination in allopolyploid clawed frogs (xenopus)

遗传学家感兴趣的是导致生殖不相容的基因的身份和影响。另一个重要的分子遗传学问题是，在基因组完全复制后，多倍体生物如何保持关键的表型，如性别决定。这项拟议的研究将利用多倍体爪蛙(非洲爪蛙)来研究与繁殖不亲和性相关的基因的丰度和影响，并缩小决定性别的遗传区域。我们将利用这一群体可用的大量技术资源，包括完整的基因组序列、表达序列标签数据库和预制微阵列芯片。我们还将利用和探索使这些青蛙易于进行遗传研究的自然特征，包括生产可行的杂交和回交，以及通过多倍化形成的副蛙的差异表达。我们的具体目标是(A)利用表型关联作图进一步缩小爪蛙的性别决定区域，(B)量化导致物种间繁殖不亲和性的基因的数量和作用，以及(C)测试表达差异与回交杂种育性之间的相关性。这项工作的结果将对我们理解基因和基因组复制--发生在包括人类祖先在内的整个生命树上的基本遗传过程--产生影响。这项研究还将识别男性偏向表达的基因，阐明物种之间生殖不亲和性的遗传基础，并为基因组复制后性别决定的研究提供基因组框架。这项工作将在NSERC的优先领域培训麦克马斯特的研究生和本科生，包括分子遗传学、功能基因组学、生物信息学和计算生物学。

Of interest to geneticists is the identity and impact of genes that cause reproductive incompatibilities. Another important molecular genetic question asks how polyploid organisms maintain crucial phenotypes, such as sex determination, in the wake of complete genome duplication. The proposed research will employ polyploid clawed frogs (Xenopus) to investigate the abundance and effect of genes involved with reproductive incompatibilities and also to narrow down the genetic region that determines their sex. We will utilize the considerable technical resources available for this group, including a complete genome sequence, expressed sequence tag databases, and prefabricated microarray chips. We will also utilize and explore natural characteristics that make these frogs amenable to genetic inquiry, including the production of viable hybrids and backcrosses, and differential expression of paralogs formed by polyploidization. Our specific goals are to (a) use phenotype association mapping to further narrow down the sex determining region of clawed frogs, (b) quantify the number and effect of genes that cause reproductive incompatibilities between species, and (c) test for a correlation between expression divergence and fertility of backcross hybrids. Results of this work will have implications for our understanding of gene and genome duplication - fundamental genetic processes that occurred throughout the tree of life including in human ancestors. This research will also identify genes with male-biased expression, elucidate the genetic basis of reproductive incompatibilities between species, and provide a genomic framework for study of sex determination after genome duplication. This work will train graduate and undergraduate students at McMaster in NSERC priority areas including molecular genetics, functional genomics, bioinformatics, and computational biology.