Species demography and the distribution of fitness effects of new deleterious mutations in wild tomatoes (Solanum section Lycopersicon)

野生番茄原产于南美洲西部和加拉帕戈斯群岛，是一种进化植物模式系统。虽然野生番茄的起源相对较新，但它们表现出相当大的形态和遗传变异。利用物种范围的样本，我们的第一个目标是分析番茄分支的分化过程，并估计物种人口统计学(特别是自交不亲和物种)。这种方法是基于我们最近的理论分析，即即使在高迁移水平下，采样方案也会影响序列数据中的系谱签名。第二个目标是使用从当地人口中收集的样本来估计有害突变的适应度影响的分布。由于有害突变发生在全基因组水平上，它们可能会影响多态的位置频率谱，从而对当地人口统计学产生影响。总体而言，这个项目将促进我们对细分的非平衡总体中抽样对人口统计推断的影响的理解。

Wild tomato species, native to western South America and the Galapagos Islands, are an evolutionary plant model system. Although wild tomatoes have a relatively recent origin, they exhibit considerable morphological and genetic variation. Using species-wide samples, our first goal is to analyze the divergence process of the tomato clade and estimate the species demography (in particular, of the self-incompatible species). This approach is based on our recent theoretical analyses that sampling schemes can influence genealogical signatures in sequence data even under high levels of migration. The second goal is to use samples collected from local populations to estimate the distribution of fitness effects of deleterious mutations. Since deleterious mutations occur at a genome-wide level, they may affect the site frequency spectrum of polymorphisms and hence have an effect on the demography of local populations. In general, this project will advance our understanding of the effects of sampling on demographic inferences in subdivided nonequilibrium populations.