Eyre-Walker A, Gaut R L, Hilton H, Feldman D L, Gaut B S
Department of Plant Sciences and Center for Theoretical and Applied Genetics, Rutgers University, New Brunswick, NJ 08902, USA.
Proc Natl Acad Sci U S A. 1998 Apr 14;95(8):4441-6. doi: 10.1073/pnas.95.8.4441.
Maize (Zea mays ssp. mays) is genetically diverse, yet it is also morphologically distinct from its wild relatives. These two observations are somewhat contradictory: the first observation is consistent with a large historical population size for maize, but the latter observation is consistent with strong, diversity-limiting selection during maize domestication. In this study, we sampled sequence diversity, coupled with simulations of the coalescent process, to study the dynamics of a population bottleneck during the domestication of maize. To do this, we determined the DNA sequence of a 1,400-bp region of the Adh1 locus from 19 individuals representing maize, its presumed progenitor (Z. mays ssp. parviglumis), and a more distant relative (Zea luxurians). The sequence data were used to guide coalescent simulations of population bottlenecks associated with domestication. Our study confirms high genetic diversity in maize-maize contains 75% of the variation found in its progenitor and is more diverse than its wild relative, Z. luxurians-but it also suggests that sequence diversity in maize can be explained by a bottleneck of short duration and very small size. For example, the breadth of genetic diversity in maize is consistent with a founding population of only 20 individuals when the domestication event is 10 generations in length.
玉米（Zea mays ssp. mays）具有遗传多样性，但其形态也与其野生近缘种明显不同。这两个观察结果有些矛盾：第一个观察结果与玉米庞大的历史种群规模相符，但后一个观察结果与玉米驯化过程中强大的、限制多样性的选择相符。在本研究中，我们对序列多样性进行采样，并结合溯祖过程模拟，来研究玉米驯化过程中种群瓶颈的动态变化。为此，我们测定了代表玉米、其假定祖先（小颖玉米Z. mays ssp. parviglumis）和一个亲缘关系更远的近缘种（繁茂玉米Zea luxurians）的19个个体的adh1基因座1400bp区域的DNA序列。序列数据被用于指导与驯化相关的种群瓶颈的溯祖模拟。我们的研究证实了玉米具有高遗传多样性——玉米包含其祖先中75%的变异，且比其野生近缘种繁茂玉米更为多样——但这也表明玉米中的序列多样性可以用一个持续时间短且规模非常小的瓶颈来解释。例如，当驯化事件持续10代时，玉米遗传多样性的广度与仅由20个个体组成的奠基群体相符。
