GENETIC-VARIABILITY IN THE 3 SUBSPECIES OF MARCHANTIA-POLYMORPHA (HEPATICAE) - ISOZYMES, RFLP AND RAPD MARKERS

Three subspecies of Marchantia polymorpha have been recently character ized by isozyme patterns, ecology and morphological characters. To con firm their taxonomic status and to better understand their relationshi ps and genetic variability, a previous study on enzyme polymorphism wa s extended to additional colonies and enzymes. A parallel study was do ne with DNA markers derived from restriction fragment length polymorph ism (RFLP) and random amplified polymorphic DNA (RAPD). Results obtain ed with these different approaches (protein and DNA level) all support the taxonomic distinctness of the subspecies. Genetic similarity with in subspecies was found to be high over wide geographic areas, and low among subspecies. The genetic divergence of the three subspecies may be taken to illustrate a case of speciation with adaptation to differe nt ecological niches, and subsequent reproductive isolation. The hybri d origin of Marchantia polymorpha subsp. ruderalis, postulated in the past, is not supported by our data.