Interspecific evolution in plant microsatellite structure

Several intragenically linked microsatellites have been identified in the f loral regulatory genes A. sandwicense APETALA1 (ASAP1) and A. sandwicense A PETALA3/TM6 (ASAP3/TM6) in 17 species of the Hawaiian and North American Ma diinae (Asteraceae). Thirty-nine microsatellite loci were observed in the i ntrons of these two genes, suggesting that they are hotspots for microsatel lite formation. The sequences of four of these microsatellites were mapped onto the phylogenies of these floral regulatory genes, and the structural e volution of these repeat loci was traced. Both nucleotide substitutions and insertion/deletion mutations may be responsible for the formation of perfe ct microsatellites from imperfect repeat regions (and vice versa). (C) 2000 Published by Elsevier Science B.V. All rights reserved.