Spatial genetic structure across a hybrid zone between European rabbit subspecies.

Ignacio Doadrio,Fernando Alda

doi:10.7717/peerj.582

Abstract

The Iberian Peninsula is the only region in the world where the two existing subspecies of the European rabbit (Oryctolagus cuniculus) naturally occur and hybridize. In this study we explore the relative roles of historical and contemporary processes in shaping the spatial genetic structure of the rabbit across its native distribution range, and how they differently affect each subspecies and the hybrid zone. For that purpose we obtained multilocus genotypes and mitochondrial DNA data from 771 rabbits across most of the distribution range of the European rabbit in Spain. Based on the nuclear markers we observed a hierarchical genetic structure firstly comprised by two genetic groups, largely congruent with the mitochondrial lineages and subspecies distributions (O. c. algirus and O. c. cuniculus), which were subsequently subdivided into seven genetic groups. Geographic distance alone emerged as an important factor explaining genetic differentiation across the whole range, without the need to invoke for the effect for geographical barriers. Additionally, the significantly positive spatial correlation up to a distance of only 100 km supported the idea that differentiation at a local level is of greater importance when considering the species overall genetic structure. When looking at the subspecies, northern populations of O. c. cuniculus showed more spatial genetic structure and differentiation than O. c. algirus. This could be due to local geographic barriers, limited resources, soil type and/or social behavior limiting dispersal. The hybrid zone showed similar genetic structure to the southern populations but a larger introgression from the northern lineage genome. These differences have been attributed to selection against the hybrids rather than to behavioral differences between subspecies. Ultimately, the genetic structure of the rabbit in its native distribution range is the result of an ensemble of factors, from geographical and ecological, to behavioral and molecular, that hierarchically interact through time and space.

Highlights

IntroductionThis genetic structure may be a consequence of many factors
In most species, populations are genetically structured
All the other localities showed a mixture of both lineages, there was a clear predominance of B haplotypes in the northeast of the Iberian Peninsula and Balearic islands, A haplotypes in the southwest, and a mixture of both in the center of the Peninsula (Table 1)

Summary

Introduction

This genetic structure may be a consequence of many factors. Geographical factors may lead to vicariant events and divide populations (Knowles & Carstens, 2007), or ecological factors may determine habitat suitability across space, and population connectivity. How to cite this article Alda and Doadrio (2014), Spatial genetic structure across a hybrid zone between European rabbit subspecies. Behavioral traits can shape the population structure of species, such as family groups in primates, or colonies of social insects (Shoemaker & Ross, 1996; Bradley et al, 2002). Genetic structure will result from the balance between gene flow, drift, and the time necessary to reach a balance between both forces (Hutchison & Templeton, 1999)

Objectives

Methods

Results

Conclusion