Recurrent hybridization without homoeologous chromosome paring in the Dryopteris varia complex (Dryopteridaceae)

Abstract

Controlling combining chromosomes in meiosis is necessary to maintain genome constitutions. The Dryopteirs varia complex is one of the apogamous fern groups which perform recurrent hybridization with unequal meiosis, and produce spores after meiosis of the genome doubling in spore mother cells. We analyzed five low-copy nuclear markers (AK1, EST, GapCp, G6PD, and PgiC) and three regions of plastid DNA (rbL, ndhF and trnL-F). The genetic constitution of the five nuclear markers was the same in the D. varia complex. Therefore, recurrent hybridization seemed to be occurred without homoeologous chromosome paring.