CONSERVATION OF (GA)(N) MICROSATELLITE LOCI BETWEEN QUERCUS SPECIES

Microsatellite (simple sequence repeat, SSR) amplification was perform ed in eight different members of the Fagaceae family by using sets of primers developed from sessile oak, Quercus petraea. In total, 136 cas es of heterologous amplification were carried out, and 66% resulted in interpretable amplification products. From these, 12 PCR amplificatio n products were sequenced and all 12 contained a sequence homologous t o the original locus from Q. petraea. Although SSR primers worked even across different genera, with increasing evolutionary distance there was a clear tendency for decreasing ability to successfully amplify lo ci and a decreasing proportion of polymorphism amongst those markers w hich could be amplified. Two of the loci, ssrQpZAG46 and ssrQpZAG110, were polymorphic in all Quercus species tested. Only at one locus, ssr QpZAG58, a specific PCR product could be amplified in all species anal ysed. For four loci found in two species, we observed significant inte rspecies differences in the size range of the amplified alleles. Seque nce analysis of two alleles showed that the size differences are not o nly due to variations in the number of (GA) repeats but also to an ins ertion of approximately 80 nucleotides in the flanking region. Our fin dings prove the usefulness of SSR markers within and amongst closely r elated genera of plants.