Molecular Phylogenetic Analysis Of Marine Sedentary Polychaeta

The polychaeta is the largest class in the phylum Annelid. They play a very important role in the ecology of marine environment. Being also economically important animals as the food of fishes and shrimp, they occupy an important position in aquaculture. Polychaeta can also be used to indicate the quality of water and the polluted condition of sediments. So it is necessary to make the accurate taxology and phylogeny of polychaeta. But in the past, related research was poor because of its diversity, and it led to the confusion of taxology of polychaeta. Molecular phylogenetic analysis provides a new method for polychaeta. Combining the morphological characters, polychaetes were assessed for their phylogenetic position in parsimony analyses of 18S rRNA. The segments of COâ… sequences of polychaetes sampled from Xiamen coast were analyzed at the same time. Other samples were collected from Chinese polymetallic nodule mining area by R.V.Da Yang Yi Hao on the DY105-12/14 and DY105-17 cruises. The results as follows:1.Statistics of genetic types used in phylogenetic analysis of polychaetes had been done. The results showed that mitochondrial genes accounted 63.7 percent to total sequences used in phylogenetic analysis of polychaetes. rDNA genes was the most common molecular marker, while it occupied 33.7 percent. mRNA sequences of functional proteins increased rapidly. By doing this work, we collected information on all kinds of genes, and it provided enough information for us to choose correct markers.2. We developed an efficient method to extract DNA for PCR from weeny polychaete samples fixed by 70% ethanol. We also compared the quality of DNA template of different samples fixed by different methods. As a result, the quality of DNA template extracted from samples fixed by 70% ethanol is well.3.Amplifying and sequencing 18S rRNA partial sequences of species sampled from Xiamen coast and from Pacific. COâ… sequences of Xiamen coastal polychaeta were also amplifying. Based on related 18S rRNA...