Restriction endonuclease analysis of chloroplast and mitochondrial DNAs from Bryopsis (Derbesiales, Chlorophyta)

Abstract

The restriction patterns of chloroplast (cp) and mitochondrial (mt) DNAs isolated from Bryopsis maxima Okamura, B. plumosa (Hudson) C. Agardh and one unidentified Bryopsis species (B. sp.) were compared with EcoRI, EcoRV and BamHI. From the resultant DNA fragments, the molecular sizes of the algal cp and mtDNAs were estimated to be about 150 and 220 kilobase pairs (kbp), respectively. In the case of cpDNA, except for most fragments identical in size among the three algal species, fragments of common sizes were contained only by B. maxima and B. sp. but there were none in common among other combinations of the algae. The sequence divergences of organelle DNA fragments between B. maxima-B. sp., B. plumosa-B. sp. and B. maxima-B. plumosa were calculated as 1.4, 5.4 and 5.1 % for cpDNAs, and for mtDNAs, as 4.2, 8.8 and 8.6%, respectively. These results suggest that B. sp. is a different species from the other two Bryopsis algae and has a closer phylogenetic relationship to B. maxima than to B. plumosa. The evolution rate of algal mtDNAs is more rapid than that of cpDNAs as seen in higher plants. In order to identify marine algal species and to know their phylogenetic relationships, restriction enzyme analysis of the algal organelle DNAs is suggested to be useful.