Indications of Genetic Admixture in the Transition Zone between Fagus sylvatica L. and Fagus sylvatica ssp. orientalis Greut. &amp; Burd

Markus Müller,Ioannis Tsiripidis,Precious Annie Lopez,Aristotelis C Papageorgiou,Oliver Gailing

doi:10.3390/d11060090

Indications of Genetic Admixture in the Transition Zone between Fagus sylvatica L. and Fagus sylvatica ssp. orientalis Greut. & Burd

Markus Müller, Ioannis Tsiripidis + Show 3 more

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https://doi.org/10.3390/d11060090

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Abstract

Two subspecies of European beech (Fagus sylvatica L.) can be found in southeast Europe: Fagus sylvatica ssp. sylvatica L. and Fagus sylvatica ssp. orientalis (Lipsky) Greut. & Burd. (Fagus orientalis Lipsky). In a previous study, based on genetic diversity patterns and morphological characters, indications of hybridization between both subspecies were found in northeastern Greece, a known contact zone of F. sylvatica and F. orientalis. Nevertheless, potential genetic admixture has not been investigated systematically before. Here, we investigated genetic diversity and genetic structure of 14 beech populations originating from Greece and Turkey as well as of two reference F. sylvatica populations from Germany based on nine expressed sequence tag-simple sequence repeat (EST-SSR) markers. Very low genetic differentiation was detected among F. sylvatica populations (mean GST: 0.005) as well as among F. orientalis populations (mean GST: 0.008), but substantial differentiation was detected between populations of the two subspecies (mean GST: 0.122). Indications for hybridization between both subspecies were revealed for one population in Greece. One of the genetic markers showed specific allele frequencies for F. sylvatica and F. orientalis and may be used as a diagnostic marker in future studies to discriminate both subspecies.

Highlights

In southeast Europe, two subspecies of Fagus sylvatica L. can be found: Fagus sylvatica ssp. sylvatica and Fagus sylvatica ssp. orientalis (Lipsky) Greut & Burd. [1,2], whereby the status of these two taxa as subspecies or species and their phylogeny still needs to be clarified [3,4]
F. sylvatica is distributed over large areas in Europe, whereas F. orientalis ranges from the southeastern Balkan to northern Iran [5]
Four potential F. sylvatica populations were sampled in Northwest Greece (Alevitsa, Varnuntas, Aetomilitsa, and Tsepelovo), and two potential F. sylvatica populations were sampled in West Rodopi in Northeast Greece (Frakto, Lepida)

Summary

Introduction

In southeast Europe, two subspecies of Fagus sylvatica L. can be found: Fagus sylvatica ssp. sylvatica (hereafter F. sylvatica) and Fagus sylvatica ssp. orientalis (Lipsky) Greut & Burd. (hereafter F. orientalis) [1,2], whereby the status of these two taxa as subspecies or species and their phylogeny still needs to be clarified [3,4]. In southeast Europe, two subspecies of Fagus sylvatica L. can be found: Fagus sylvatica ssp. F. sylvatica is distributed over large areas in Europe, whereas F. orientalis ranges from the southeastern Balkan to northern Iran [5]. Several studies were conducted to investigate morphological and genetic variation patterns within the distribution area of the two subspecies. Conducted a morphological analysis of beech populations covering the range of species in western Eurasia. Morphological forms resembling F. sylvatica were found in western parts of Greece, whereas morphological types resembling F. orientalis were found in the eastern parts of the country [7]. Populations of F. sylvatica and F. orientalis were investigated using different types of genetic markers such as amplified fragment-length polymorphisms (AFLPs), chloroplast microsatellites, internal transcribed

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