Rapid vertebrate speciation via isolation, bottlenecks, and drift

• 成果类型: Article
• 署名作者: Black, Andrew N.; Heenkenda, Erangi J.; Mathur, Samarth; Willoughby, Janna R.; Pierce, Brian L.; Turner, Sarah J.; Rizzuto, David; DeWoody, Andrew
• 署名单位: Purdue University System; Purdue University; University System of Ohio; Ohio State University; Auburn University System; Auburn University; Texas A&M University System; Texas A&M University College Station; Purdue University System; Purdue University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-15381
• DOI: 10.1073/pnas.2320040121
• 发表日期: 2024-05-28
• 关键词: evolutionarily-significant-units; cyprinodon-variegatus; genetic-evidence; CONSERVATION; pupfish; divergence; reinforcement; hybridization; populations; diversity

摘要

Speciation is often driven by selective processes like those associated with viability, mate choice, or local adaptation, and speciation genes have been identified in eukaryotic lineages. In contrast, neutral processes are rarely considered as the primary drivers of speciation, especially over short evolutionary timeframes. Here, we describe a rapid vertebrate speciation event driven primarily by genetic drift. The White pupfish ( Cyprinodon tularosa ) is endemic to New Mexico's Tularosa Basin where species is currently managed as two Evolutionarily significant units (ESUs) and international conservation concern (Endangered). Whole - genome resequencing from each ESU showed remarkably high and uniform levels of differentiation across entire genome (global F-ST approximate to 0.40). Despite inhabiting ecologically dissimilar springs and streams, our whole - genome analysis revealed no discrete islands of divergence indicative of strong selection, even when we focused on an array of candidate Demographic modeling of the joint allele frequency spectrum indicates the two split only similar to 4 to 5 kya and that both ESUs have undergone major bottlenecks within last 2.5 millennia. Our results indicate the genome - wide disparities between the ESUs are not driven by divergent selection but by neutral drift due to small population sizes, geographic isolation, and repeated bottlenecks. While rapid speciation is driven by natural or sexual selection, here we show that isolation and drift have speciation within a few thousand generations. We discuss these evolutionary insights in light of the conservation management challenges they pose.