Sequences And Phylogeny Analysis Of ITS And 18S RDNA Of Three Species In Chlorophyta

We got the overall length of ITS region and 18S rDNA sequences about Ulva prolifera, Ulva pertusa and Monostroma grevillei. The sequences were aligned using Clustal X, and further manually adjusted using BioEdit. For comparative analysis, other 16 green alga sequences were taken from the GenBank were compared with U. prolifera, U. pertusa and M. grevillei. We used MEGA3.1 (neighbor-joining method) to study the relationship of different species to construct the phylogenetic tree, and detect the degree of bootstrap confidence from 1000 replicates.Although the thallus of U. pertusa is thick with many holes, it is different from U. prolifera in morphology. From the phylogenetic tree constructed from 18S sequences, it can be found that U. pertusa and U. prolifera group in one branch, while U. lactuca, U. fenestrate, and U. californica are in another branch. From the phylogenetic tree constructed from ITS sequences, U. prolifera and U. pertusa are not in one branch. But U. pertusa and U. fenestrate grouped in one branch. No matter the phylogenetic tree constructed from ITS sequences or 18S sequences, it is clear that the clade of Ulvaceae comprised of Chloropelta, Enteromorpha, Percursaria, Ulva and Ulvaria. These results are consistent with that of Hayden and Waaland which proved that in different areas had the same conclusion.