Conservation of nuclear SSR loci reveals high affinity of Quercus infectoria ssp. veneris A. Kern (Fagaceae) to section Robur

TL;DR

This study demonstrates that nuclear SSR loci conserved across oak species reveal a high genetic affinity of Quercus infectoria ssp. veneris to section Robur, despite its limited distribution and fragmentation in Cyprus.

Contribution

The paper shows successful cross-species amplification of SSR loci and clarifies the genetic relationship of Q. infectoria ssp. veneris to section Robur using molecular markers.

Findings

High genetic diversity in Q. infectoria despite limited distribution

SSR loci match patterns of section Robur species

No evidence of interspecific introgression with distant species

Abstract

Conservation of 16 nuclear microsatellite loci, originally developed for Quercus macrocarpa (section Albae), Q. petraea, Q. robur (section Robur) and Q. myrsinifolia, (subgenus Cyclobalanopsis) was tested in a Q. infectoria ssp. veneris population from Cyprus. All loci could be amplified successfully and displayed allele size and diversity patterns that match those of oak species belonging to the section Robur. At least in one case, limited amplification and high levels of homozygosity support the occurrence of 'null alleles', caused by a possible mutation in the highly conserved primer areas, thus hindering PCR. The sampled population exhibited high levels of diversity despite the very limited distribution of this species in Cyprus and extended population fragmentation. Allele sizes of Q. infectoria at locus QpZAG9 partially match those of Q. alnifolia and Q. coccifera from neighboring populations. However, sequencing showed homoplasy, excluding a case of interspecific introgression with the latter, phylogenetically remote species. Q. infectoria ssp. veneris sequences at this locus were concordant to those of other species of section Robur, while sequences of Quercus alnifolia and Quercus coccifera were almost identical to Q. cerris.