Comparison of ITS RFLP patterns of Gracilaria (Rhodophyceae, Gracilariales) populations from Chile and New Zealand and an examination of interfertility of Chilean morphotypes

Restriction fragment length polymorphism (RFLP) patterns of the internal tr anscribed spacer (ITS) of the nuclear ribosomal cistron and crossability tr ials were used to characterize four morphotypes of Gracilaria from Lenga, I sla Santa Maria and Maullin, Chile, and two morphotypes from sites in New Z ealand. PCR products from all Chilean morphotypes resulted in a major singl e band of ca. 1198 bp. ITS-RFLP profiles generated with the restriction enz ymes Cla I, Hae III, Pst I, Hha I, Rsa I and Taq I, were identical in all c ases. All crosses within, as well as between, morphotypes resulted in cysto carp differentiation, with the production of viable carpospores. Based upon these data, it is concluded that the four morphotypes from Chile correspon d to a single species, G. chilensis, and that the ITS-RFLP pattern is a use ful marker to predict genetic relatedness at the specific level in Gracilar ia. A comparison of the ITS-RFLP patterns of the Chilean morphotypes with t he patterns of two samples of G. chilensis from New Zealand revealed that t he sample from Scorching Bay, Wellington, fits the Chilean ITS-RFLP pattern s. The population from Blockhouse Bay, Auckland, appears to correspond to a nother species.