The Population Genetics of Mitochondrial Heteroplasmy in a Gynodioecious Plant

植物和动物在线粒体中携带DNA，除了核染色体上携带的大多数基因之外。在开花植物中，线粒体DNA（mtDNA）通常仅从母亲遗传，因此个体内的mtDNA拷贝是相同的。最近对植物蝇子草（Silene vulgaris）的研究表明，mtDNA的遗传有时来自母亲和父亲，导致后代中mtDNA分子的异质性混合（异质性）。本研究将通过实验性的杂交，探讨线粒体DNA的非母系遗传频率。在温室中进行的，并记录的频率和程度的异质性在自然种群，使用分子生物学的工具。结果将是有价值的人口生物学家，因为mtDNA是作为遗传标记在许多类型的研究，假设母性遗传。这一假设只在相对较少的物种中得到了直接的检验，而且非母系遗传的后果还没有得到很好的理解。这些结果也将引起应用生物学家的兴趣，他们的目标是开发具有经济重要性的植物品系，这些植物能够产生高比例的雌性用于育种目的，因为植物的性别决定通常可以追溯到线粒体基因。

Plants and animals carry DNA in their mitochondria, in addition to the majority of genes that are carried on nuclear chromosomes. In flowering plants the mitochondrial DNA (mtDNA) is often inherited from the mother only, such that the copies of mtDNA within an individual are identical. Recent studies of the plant Silene vulgaris showed that inheritance of mtDNA is sometimes from both the mother and father, resulting in a heterogeneous mix of mtDNA molecules in the offspring (heteroplasmy). This study will investigate the frequency of non-maternal inheritance of mtDNA through experimental crosses of S. vulgaris conducted in the greenhouse, and document the frequency and magnitude of heteroplasmy in natural populations, using the tools of molecular biology.The results will be of value to population biologists because mtDNA is used as a genetic marker in many types of studies, under the assumption of maternal inheritance. This assumption has only been tested directly in relatively few species, and the consequences of non-maternal inheritance are not well understood. The results will also interest applied biologists whose goal is to develop lines of economically important plants that produce a high proportion of females for breeding purposes, given that sex determination in plants is often traced to mitochondrial genes.