Genome-wide assessment elucidates connectivity and the evolutionary history of the highly dispersive marine invertebrate Littoraria flava (Littorinidae: Gastropoda)

Thainá Cortez,Sónia C S Andrade,Rafael V Amaral,Thadeu Sobral-Souza

doi:10.1093/biolinnean/blab055

Abstract

Abstract An important goal of marine population genetics is to understand how spatial connectivity patterns are influenced by historical and evolutionary factors. In this study, we evaluate the demographic history and population structure of Littoraria flava, a highly dispersive marine gastropod in the Brazilian intertidal zone. To test the hypotheses that the species has (1) historically high levels of gene flow on a macrogeographical spatial scale and (2) a distribution in rocky shores that consists of subpopulations, we collected specimens along the Brazilian coastline and combined different sets of genetic markers (mitochondrial DNA, ITS-2 and single nucleotide polymorphisms) with niche-based modelling to predict its palaeodistribution. Low genetic structure was observed, as well as high gene flow over long distances. The demographic analyses suggest that L. flava has had periods of population bottlenecks followed by expansion. According to both palaeodistribution and coalescent simulations, these expansion events occurred during the Pleistocene interglacial cycles (21 kya) and the associated climatic changes were the probable drivers of the distribution of the species. This is the first phylogeographical study of a marine gastropod on the South American coast based on genomic markers associated with niche modelling.

Highlights

An important goal of population genetics studies in marine ecosystems is understanding how connectivity patterns, both spatial and temporal, are influenced by historical and evolutionary factors. When it comes to dispersion and connectivity in marine ecosystems, the role of historical and evolutionary factors over population dynamics and structure still remains enigmatic
We evaluated the demographic history and population structure of Littoraria flava, a highly dispersive and widely distributed marine gastropod on the Brazilian intertidal zone, to predict the effects of such factors on intrapopulation divergence
The neutrality tests and the haplotype networks suggest that L. flava had experienced population bottleneck followed by population expansion. Both paleodistribution and coalescent simulations highlight that expansion events occurred in the Southeastern coastline during the Pleistocene interglacial cycles (21 kya). This is the first study on the South American coast that highlights the demographic history on a marine gastropod based on genomic markers associated with niche modelling

Summary

Introduction

An important goal of population genetics studies in marine ecosystems is understanding how connectivity patterns, both spatial and temporal, are influenced by historical and evolutionary factors. Thainá Cortez USP: Universidade de Sao Paulo Rafael Viana Amaral USP: Universidade de Sao Paulo

Results

Conclusion