Sequence Coloning And Analysis Of Ribosomal Gene Cluster In Three Types Of Economic Red Algal

In this article, we analyzed small and large subunit ribosomal RNA genes (18SrDNA and28S rDNA), intergenic spacer (IGS) sequences of economic red algalPorphyra species and Gracilaria lemaneiformis in China, comparing the sequencesdistinctions and genetic variations, to provide the molecular proof for phylogeny study,germplasm resources investigation, genetic diversity protecting, and strain breeding andimproving.We extracted the template DNA of the wild thalli from Qindao and the cultivatedthalli of Porphyra yezoensis from Lianyungang, the cultivated thalli of Porphyrahaitanensis and Gracilaria lemaneiformis from Putian by using improved CTABmethod, and the template DNA were amplified, sequenced and analyzed. The length of18S rDNA are respectively2271bp,3186bp and1724bp.The results are as followes:The18S rDNA sequences are essentially identical between the two different resourcesof P. yezoensis. The genetic distance between P. yezoensis and P. haitanensis is only0.054. The content of G+C in those red algal are varied from47%to50%.The most of large subunit ribosomal RNA gene sequences (28S rDNA) was firsttime applied to analyze the genetic variability of the two Porphyra species and G.lemaneiformis. The lengths of them are respectively2323bp,1998bp and2808bp. Thecontent of G+C in Porphyra species is close to53%while the value of G. lemaneiformisis only50.09%. The result of splicing sequences shown the sequences of two differentresources of P. yezoensis had no different site while the genetic distance between P.yezoensis and P. haitanensis are far away from each other (0.096) and the homology isonly89.39%.The5’ end of intergenic spacer region (IGS) was first time applied to analyze thetwo different populations of P. yezoensis. The500bp lenth sequences between twotemplates have24variable sites. On the other hand, the partial sequence (720bp) of3’end in IGS of cultivatied thaii of P. yezoensis was also firstly obtained and was used to compare with P. haitanensis in previous work. The result of alignment shows the3’ endof IGS in two species of Porphyra has many large variable sites.