Unraveling the evolutionary history of the nematode Pristionchus pacificus: from lineage diversification to island colonization

Ecology and Evolution

Angela McGaughran¹  Katy Morgan¹ 

[1] Department for Evolutionary Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany

关键词: Approximate Bayesian Computation;    colonization;    modeling;    nematode;    population genetics;    Pristionchus pacificus;   

DOI  :  10.1002/ece3.495

来源: Wiley

【 摘 要 】

Abstract

The hermaphroditic nematode Pristionchus pacificus is a model organism with a range of fully developed genetic tools. The species is globally widespread and highly diverse genetically, consisting of four major independent lineages (lineages A, B, C, and D). Despite its young age (~2.1 Ma), volcanic La Réunion Island harbors all four lineages. Ecological and population genetic research studies suggest that this diversity is due to repeated independent island colonizations by P. pacificus. Here, we use model-based statistical methods to rigorously test hypotheses regarding the evolutionary history of P. pacificus. First, we employ divergence analyses to date diversification events among the four “world” lineages. Next, we examine demographic properties of a subset of four populations (“a”, “b”, “c”, and “d”), present on La Réunion Island. Finally, we use the results of the divergence and demographic analyses to inform a modeling-based approximate Bayesian computation (ABC) approach, where we test hypotheses about the order and timing of establishment of the Réunion populations. Our dating estimates place the recent common ancestor of P. pacificus lineages at nearly 500,000 generations past. Our demographic analysis supports recent (<150,000 generations) spatial expansion for the island populations, and our ABC approach supports c>a>b>d as the most likely colonization order of the island populations. Collectively, our study comprehensively improves previous inferences about the evolutionary history of P. pacificus.

【 授权许可】

CC BY   
© 2013 The Authors. Ecology and Evolution published by Blackwell Publishing Ltd.

Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.