Investigation of the bottleneck leading to the domestication of maize

TLDR

Maize is genetically diverse yet morphologically distinct from its wild relatives, a paradox implying a large historical population size coupled with strong diversity‑limiting selection during domestication. The study aims to examine the dynamics of a domestication bottleneck by sampling sequence diversity and performing coalescent simulations. Researchers sequenced a 1,400‑bp region of the Adh1 locus from 19 individuals of maize, its progenitor *Z. mays* ssp.

Abstract

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 Adh 1 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.