An ancient origin of the naked grains of maize

• 成果类型: Article
• 署名作者: Fairbanks, Regina A.; Ross-Ibarra, Jeffrey
• 署名单位: University of California System; University of California Davis; University of California System; University of California Davis; University of California System; University of California Davis
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-10102
• DOI: 10.1073/pnas.2503748122
• 发表日期: 2025-06-24
• 关键词: zea-mays; morphological differences; experimental evolution; population-structure; genetic-locus; seed dormancy; domestication; selection; teosinte; sequence

摘要

Adaptation to novel environments requires genetic variation, but whether adaptation been long used as a model to understand evolutionary processes, providing information not only on the phenotypes selected but also, in many cases, an understanding of the causal loci. For each of the causal loci that have been identified in maize, the selected allele can be found segregating in natural populations, consistent with their origin as standing genetic variation. The sole exception to this pattern is the well-characterized domestication locus tga1 (teosinte glume architecture1), which has long been thought to be an example of selection on a de novo mutation. Here, we use a large dataset of maize and teosinte genomes to reconstruct the origin and evolutionary history of tga1. We first estimated the age of tga1-maize using a genealogy-based method, finding that the allele arose approximately 42,000 to 49,000 y ago, predating the beginning of maize domestication. We also identify tga1-maize in teosinte populations, indicating that the allele can survive in the wild. Finally, we compare observed patterns of haplotype structure and mutational age distributions near tga1 with simulations, finding that patterns near tga1 in maize better resemble those generated under simulated selective domestication likely drew upon standing genetic variation at tga1 and cement the importance of standing variation in driving adaptation during domestication.