Wheat alleles introgress into selfing wild relatives: empirical estimates from approximate Bayesian computation in Aegilops triuncialis. Issue 20 (8th October 2014)

• Record Type: Journal Article
• Authors: Pajkovic, Mila; Lappe, Sylvain; Barman, Rachel; Parisod, Christian; Neuenschwander, Samuel; Goudet, Jerome; Alvarez, Nadir; Guadagnuolo, Roberto; Felber, François; Arrigo, Nils
• Is Part Of: Molecular ecology. Volume 23:Issue 20(2014)
• Page Start: 5089
• Page End: 5101
• Publication Date: 2014-10-08
• Subjects: Molecular ecology -- Periodicals; Molecular population biology -- Periodicals; 576
• DOI: 10.1111/mec.12918
• Languages: English
• ISSNs: 0962-1083

Abstract

<abstract abstract-type="main" id="mec12918-abs-0001"> <title>Abstract</title> <p>Extensive gene flow between wheat (<italic>Triticum</italic> sp.) and several wild relatives of the genus <italic>Aegilops</italic> has recently been detected despite notoriously high levels of selfing in these species. Here, we assess and model the spread of wheat alleles into natural populations of the barbed goatgrass (<italic>Aegilops triuncialis)</italic>, a wild wheat relative prevailing in the Mediterranean flora. Our sampling, based on an extensive survey of 31 <italic>Ae. triuncialis</italic> populations collected along a 60 km × 20 km area in southern Spain (Grazalema Mountain chain, Andalousia, totalling 458 specimens), is completed with 33 wheat cultivars representative of the European domesticated pool. All specimens were genotyped with amplified fragment length polymorphism with the aim of estimating wheat admixture levels in <italic>Ae. triuncialis</italic> populations. This survey first confirmed extensive hybridization and backcrossing of wheat into the wild species. We then used explicit modelling of populations and approximate Bayesian computation to estimate the selfing rate of <italic>Ae. triuncialis</italic> along with the magnitude, the tempo and the geographical distance over which wheat alleles introgress into <italic>Ae. triuncialis</italic> populations. These simulations confirmed that extensive introgression of wheat alleles (2.7 × 10<sup>−4</sup> wheat immigrants for each <italic>Ae. triuncialis</italic> resident, at each generation) into <italic>Ae. triuncialis</italic> occurs despite a high selfing rate (Fis ≈ 1 and selfing rate = 97%). These results are discussed in the light of risks associated with the release of genetically modified wheat cultivars in Mediterranean agrosystems.</p> </abstract>