Population differentiation and phylogeography of Hygrophila pogonocalyx based on RAPDs fingerprints

Genetic variation of the endangered species, Hygrophila pogonocalyx Hayata (Acanthaceae), was estimated based on RAPD fingerprints. According to the c riteria of the International Union for Conservation of Nature and Nature Re sources, H. pogonocalyx is on the Red List Category due to its endangered s tatus. Entomophilous plants of H. pogonocalyx are mostly pollinated by hone ybees. Gene flow between populations is constrained by the migratory capaci ty of the pollinators. A survey based on RAPD fingerprinting using 50 rando m primers revealed the distribution of genetic variation following an "isol ation by distance" model. A hierarchical AMOVA analyses indicated significa nt differentiation between geographical regions (Phi (ct) = 0.934; P = 0.04 8), among populations (Phi (st) = 0.945; P < 0.001), and among populations within region (Phi (sc) = 0.169: P < 0.001). The differentiation between ge ographic populations may be ascribed to a long isolation since the formatio n of the Central Mountain Range 1 million years ago. In contrast to low lev els of genetic variation in many endangered species, some genetic processes avoiding selling may have evolved in H. pogonocalyx. Somatic mutation also possibly contributed to the variability maintenance within populations wit h limited size. (C) 2001 Elsevier Science B.V. All rights reserved.