Molecular evolution and ecological adaptation of gender-associated mitochondrial genomes in bivalves

我研究了双壳类软体动物中存在的一种不寻常的线粒体DNA遗传系统。与其他动物不同，一些双壳类拥有两个截然不同的性别相关的mtDNA谱系，而不仅仅是大多数动物中发现的单一的雌性传播的mtDNA谱系。我感兴趣的是测试各种假说，这些假说被提出来解释这种不寻常的线粒体DNA遗传系统的起源和维持，包括它是否允许自然选择来改善这些贻贝的精子性能，或者这些与性别相关的基因组是否可能在性别决定中发挥作用。在海洋贻贝中发现的不同的雄性和雌性传递的mtDNA基因组也经历了重组，直到最近，人们还认为这种现象不会在动物的mtDNA基因组中发生。我研究这种不同寻常的线粒体DNA遗传系统的方法包括结合精子活力分析、精子代谢活动分析和线粒体全基因组测序分析。我的研究的预期结果是促进我们对基本生物学过程的理解，主要是在双壳类中，但这种知识也将适用于其他动物群体。这些知识对遗传学家、无脊椎动物生物学家和动物学家具有普遍的兴趣和价值。在双壳类性别决定领域的纯粹知识的进步可能会在水产养殖领域以及通过人工控制性比率来发展入侵淡水贻贝物种的生物控制方面有应用。我的研究对解释线粒体DNA的进化具有广泛的意义。例如，我的研究计划将为解释一种名为Cox1的特定基因的DNA序列提供必要的数据，该基因被用作“生命条形码联盟”倡议的基础。这是一项利用DNA序列数据通过一种简单、廉价的测试来识别世界上所有动物物种的尝试。随着本土海洋和淡水贻贝面临全球气候变化和入侵双壳类物种的全球运输的威胁，对这些物种的DNA条形码的正确解释将变得越来越重要。

I study an unusual system of mitochondrial DNA inheritance present in bivalve mollusks. Unlike otheranimals, some bivalves possess two distinct gender-associated mtDNA lineages rather than just a single,female transmitted mtDNA lineage found in most animals. I am interested in testing various hypotheses thathave been proposed to explain the origin and maintenance of this unusual system of mitochondrial DNAinheritance including whether it allows for natural selection to improve sperm performance in these mussels orwhether these gender-associated genomes might play a role in sex determination. The distinct male and female transmitted mtDNA genomes found in marine mussels also undergo recombination, a phenomenon that was, until recently, not thought to occur in animal mtDNA genomes. My approach to studying this unusual system of mitochondrial DNA inheritance includes a combination of sperm motility analyses, sperm metabolic activity assays, and whole mitochondrial genome sequencing assays. The anticipated outcome of my research is to advance our understanding of basic biological processes primarily in bivalves but this knowledge will also apply to other animal groups. This knowledge would be of general interest and value to geneticists, invertebrate biologists and zoologists. The advancement of pure knowledge in the area of sex determination in bivalves may have applications in the field of aquaculture and in the development of biological controls for invasive freshwater mussel species through artificial control of sex ratios.My research has broad implications for interpreting the evolution of mitochondrial DNA. For example, my research program will provide essential data for interpreting DNA sequences for a particular gene known as Cox1, which is used as the basis of the "Consortium for the Barcode of Life" initiative. This is an attempt to use DNA sequence data to identify all species of animals in the world using a simple, inexpensive test. The correct interpretation of DNA Barcodes of native marine and freshwater mussels will be increasingly important as these species face threats from global climate change and global transport of invasive bivalve species.