Genomic evidence supports the introgression between two sympatric stickleback species inhabiting the White Sea basin

Artem Nedoluzhko,Fedor Sharko,Svetlana Tsygankova,Eugenia Boulygina,Amina Ibragimova,Anton Teslyuk,Jorge Galindo-Villegas,Sergey Rastorguev

doi:10.1016/j.heliyon.2021.e06160

Artem Nedoluzhko, Fedor Sharko + Show 6 more

Open Access

https://doi.org/10.1016/j.heliyon.2021.e06160

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Journal: Heliyon	Publication Date: Feb 1, 2021
Citations: 4	License type: cc-by

Affiliation: Kurchatov Institute, Nord University

Abstract

Interspecies hybridization is driven by a complex interplay of factors where introgression plays an important role. In the present study, the transfer of genetic material, between two quite distant fish species from different genera, through spontaneous hybridization was documented with dedicated molecular and bioinformatics tools. We investigate the genomic landscape of putative stickleback-relative introgression by carefully analyzing the tractable transposable elements (TE) on the admixed genome of some individuals of two sympatric stickleback species inhabiting northwestern Russia, namely the three-spined (Gasterosteus aculeatus) and the nine-spined (Pungitius pungitius) sticklebacks. Our data revealed that unique TE amplification types exist, supporting our proposed hypothesis that infers on the interspecific introgression. By running a restriction site-associated DNA sequencing (RAD-Seq) with eight samples of G. aculeatus and P. pungitius and subjecting further the results to a contrasting analysis by variated bioinformatic tools, we identified the related introgression-linked markers. The admixture nature observed in a single sample of the nine-spined stickleback demonstrated the possible traces of remote introgression between these two species. Our work reveals the potential that introgression has on providing particular variants at a high-frequency speed while linking blocks of sequence with multiple functional mutations. However, even though our results are of significant interest, an increased number of samples displaying the introgression are required to further ascertain our conclusions.

Highlights

Interspecific hybridization in animals has been considered for a long time as an abnormal process leading to the destruction of reproductive isolation [1]
A transposable elements (TE) analysis was performed to determine the possible presence of introgressive hybridization between the three- and nine-spined stickleback species
The fact that some nine-spined samples showed the presence of the threespined like TE provided the required evidence for conducting further analysis focused on expanding the genomic introgression knowledge between the three- and nine-spined sticklebacks

Summary

Introduction

Interspecific hybridization in animals has been considered for a long time as an abnormal process leading to the destruction of reproductive isolation [1]. In the early 20th century, supporters of this viewpoint increased after the description of postzygotic isolation (PSI) [2]. The PSI supposes that the allele incompatibility increases as the square of the genetic distance between species complicate the hybridization between distant species. While the interspecific hybridization is a natural event, it is an active participant in some evolutionary process as the speciation or the new trait acquisition. The theoretical foundations of hybridogenic speciation propose the formation of reproductive barriers between hybrids and parents as the possible genetic mechanisms [5]. Fishes are not the exception, and the interspecific hybridization events have been appreciated as a quite common event among this phylogenetic group [6,7]

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