Studies On DNA Barcoding Hydromedusae Of China Coastal Waters And Analysis Of Liriope Tetraphylla Mitochondrial Genome

Hydromedusae are a group of Hydrozoan inside the phylum Cnidaria with medusae stage.They form a great part of marine zooplanktons,and play an important role in the matter cycle and energy flow of coastal marine ecosystem.Due to its structural simplicity,morphological plasticy and complex life histories,traditionally morphological identification and systemtics analysis in this group is never to be easy.In this thesis,we studied DNA Barcoding of hydromedusae from China coatal waters using mitochondrial COI and 16S gene fragments.Meanwhile,we obtained the mitochondrial genome of Liriope tetraphylla,and analyzed the Cnidarian phylogeny based on its mt genome.And the results are listed as follows,(1)A DNA Barcoing databes based on Hydromedusae from China coastal waters was established,including 325 COI sequences and 357 16S sequences from 65 species and 38 genera of Hydromedusae,of which 107 COI sequences from 23 species and 78 16S sequences from 16 species were recorded for the first time.Another 135 photos from 27 hydromedusae species were deposited and life cycles of 6 hydromedusae species were studied.(2)We assessed the avalibility of COI and 16S sequences for Hydromedusae DNA Barcoding in China coastal waters,and proposed that both sequences were qualified to be the standard gene for Hydromedusae DNA Barcoding in China coastal waters.(3)We revealed 6 new Hydromedusae species,i.e.Clytia xiamenensis sp.nov.,C.gulangensis sp.nov.,C.tankahkeei sp.nov.,Bougainvillia gulangensis sp.nov.,Hydractinia gulangensis sp.nov.and Zanclea gulangensis sp.nov..And we proposed new techniques of combined DNA Barcoding and morphological characters in discovering cryptic and new species.(4)We assessed the prospect of vector analysis in Hydromedusas biodiversity studies in China coastal waters,and recommended that this method could be utilized to study Hydromedusae biodiversity.(5)We sequenced the mitochondrial genome of Liriope tetraphylla by designing a set of unique primers to PCR amplify the all the coded genes in its mitochondrial genome.This was the first mitochondrial genome of marine medusae frm China,and the first mitochondrial genome of Trachylina.(6)We uncoved the first tRNA-L gene in Cnidarian mitochondrial genome by analyzing the mitochondrial genome characters of Liriope tetraphylla.(7)We studied the pgylogenetics of Cnidarian based on their mitochondrial genome,and revealed the systematics of Class Anthozoa,Staurozoa,Cubozoa,Scyphozoa and Hydrozoa.