Low species barriers in halophilic archaea and the formation of recombinant hybrids

Adit Naor, Pascal Lapierre, Moshe Mevarech, R. Thane Papke, Uri Gophna*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

107 Scopus citations

Abstract

Speciation of sexually reproducing organisms requires reproductive barriers. Prokaryotes reproduce asexually but often exchange DNA by lateral gene transfer mechanisms and recombination [1], yet distinct lineages are still observed. Thus, barriers to gene flow such as geographic isolation, genetic incompatibility or a physiological inability to transfer DNA represent potential underlying mechanisms behind preferred exchange groups observed in prokaryotes [2-6]. In Bacteria, experimental evidence showed that sequence divergence impedes homologous recombination between bacterial species [7-11]. Here we study interspecies gene exchange in halophilic archaea that possess a parasexual mechanism of genetic exchange that is functional between species [12, 13]. In this process, cells fuse forming a diploid state containing the full genetic repertoire of both parental cells, which facilitates genetic exchange and recombination. Later, cells separate, occasionally resulting in hybrids of the parental strains [14]. We show high recombination frequencies between Haloferax volcanii and Haloferax mediterranei, two species that have an average nucleotide sequence identity of 86.6%. Whole genome sequencing of Haloferax interspecies hybrids revealed the exchange of chromosomal fragments ranging from 310Kb to 530Kb. These results show that recombination barriers may be more permissive in halophilic archaea than they are in bacteria.

Original languageEnglish
Pages (from-to)1444-1448
Number of pages5
JournalCurrent Biology
Volume22
Issue number15
DOIs
StatePublished - 7 Aug 2012

Funding

FundersFunder number
National Science Foundation
Directorate for Biological Sciences0830024, 0919290
United States-Israel Binational Science Foundation2007043

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