Molecular Systematic Study For Chondrus Stackh.

Chondrus is one of the most important seaweeds in the world, with raw material maily used for carrageenan extraction. Based on 19 Chondrus samples' collection and molecular analysis, which covered 15 sites of the 8 countries all over the world, we conducted its phylogenetic study and the main results are:1. Compared many other DNA extraction methods for red seaweeds, the optimized protocol was obtained for Chondrus ocellatus, which yielded 100 ng high quality DNA from 1 mg fresh algal material, and the A260/A280 ratio is between 1.68-1.90. The template DNA were feasible for restriction endonuclease digestions, polymerase chain reaction (PCR) amplifications and further molecular manipulation.2. Alignment of ITS (internal transcribed spacer) sequences for 19 Chondrus samples indicated that, the length of ITS region varied from 704 to 714 bp, G+C% between 44.3-46.9%. To Ch. crispus, the pairwise distance of ITS sequences were ranged from 0.9 to 3.3%, while compared with Ch. ocellatus, Ch. nipponicus and Ch. armatus, it became 2.3 to 4.7%, this indicated that higher divergence existed for Chondrus in interspecies than in intrespecies. Systematic analysis showed Ch. crispus from North Atlantic Ocean nations like Canada, France, Germany, England, Portugal and Ireland formed the first clade; the second group formed with Ch. spl. from Dalian, China, Ch. nipponicus from Qingdao, China and Ch. pinnulatus from Japan; the last clade included Ch. yendoi from Japan, Ch. ocellatus from Qingdao, China, all the molecular data suggested this type of red seaweeds are of oceanic distribution. It is presumed by ITS data, Chondrus collected from the third swimming beach in Qingdao consist of two species: Ch. ocellatus and Ch. nipponicus. It can be determined that Ch. spl from Dalian is Ch. nipponicus, and Ch. sp2 from Dalian is not Chondrus, possibly belong to Mazzaella scope, of Gigartinales. ITS analysis also indicated geographic location and habital environment exhibited less effects on ITS sequences variation during the evolutions of Chondrus Stackh...3. 18S rDNA sequences alignment for the 19 Chondrus samples indicated that, its length varied from 1774 to 1782 bp. Systemtic study verified the pairwise distance for interspecies of Ch. crispus were within 0.3-2.8%. No significant 18S rDNA sequence variation occurred in Chondrus interspecies. To Chondrus Stackh., 18SrDNA region is more consertive than ITS sequence. In addition, even though samples from Connemara, Ireland, it exhibited the similar morphology with Chondrus Stackh., and are regarded as Ch. crispus, 18S rDNA molecular data indicated it is not Ch. crispus.