Tests of multiple molecular markers for the identification of Great Spotted and Syrian Woodpeckers and their hybrids

Jerzy Michalczuk,Małgorzata Bujoczek,Mihaela Ilieva,Łukasz Kajtoch,Tomasz D Mazgajski,Paweł Malczyk,Allan D Mcdevitt,Tomasz Figarski

doi:10.1007/s10336-014-1040-1

Abstract

AbstractGreat Spotted and Syrian Woodpeckers (Dendrocopos major and D. syriacus) are known to hybridize in nature; however, the extent of this phenomenon is not known due to difficulties in hybrid detection based on plumage analyses. Here, we tested five markers (one mitochondrial and four nuclear) and a set of six microsatellite loci for the identification of these two Woodpeckers and their hybrids. Sequencing of DNA from 26 individuals of both Woodpeckers from different parts of their ranges: one allopatric (D. major; Norway) and two sympatric (Poland and Bulgaria) showed that both species can be clearly separated based on all sequence markers. The highest number of fixed nucleotide sites were found in the mtDNA control region and intron 5 of the transforming growth factor. Analyses of microsatellite data distinguished the two species, but all loci showed a large number of common alleles and their utility in identifying hybrids is therefore doubtful. According to the DNA sequence analyses, 2 out of 18 specimens within the sympatric range in Poland were identified as possible hybrids, most probably paternal backcrosses. Moreover, both hybrids are from synantropic populations (settled in cities), whereas none of the D. major sampled in forests and in its allopatric range (Norway) showed signs of an intermixed genotype. Further research on hybridization and introgression in woodpeckers is undoubtedly needed and could be useful for understanding ecological and ethological interactions among these species, particularly for D. syriacus, which is relatively rare in Europe.

Highlights

Hybridization is caused by incomplete or ineffective reproductive isolation mechanisms
Standard mtDNA and nucDNA genetic indices calculated for D. major and D. syriacus are presented in supplementary table 2
The data presented here show that it is possible to discriminate between D. syriacus and D. major using molecular markers

Summary

Introduction

Hybridization is caused by incomplete or ineffective reproductive isolation mechanisms. Most examples of interspecific breeding concern closely related species pairs or allospecies within superspecies groups (e.g., Randler 2002). These species are likely to be genetically compatible and often have similar life histories and behavior that enables mating. The third example may happen when at least one of the species seriously declines in part of its range In all these situations, the pressure of breeding needs may force an individual of one species (less common) to accept an individual of the other species as a mate, resulting in hybrid offspring (Hubbs 1955; Randler 2002; Aliabadian and Nijman 2007). There are examples of continuing hybridization between two species which become common in some areas (e.g., Great Spotted Dendrocopos major and Syrian Woodpeckers D. syriacus; Gorman 1997)

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Conclusion