The Tardigrade The Dna Barcoding

Barcode technique is an automatic identification technology produced by the application of computer practicing and developing, which is the information for the realization of automatic scanning and designed to achieve fast, accurate reliable and effective means of collecting data. In recent years, DNA bar coding technology has become a taxonomic study of dramatic new direction, it is a product of molecular biology and bio-informatics combination. In theory, we can get the DNA bar code of every species in the word by using this technology, and then we can use the DNA barcoding to achieve the recognition and identification of the organisms.Tardigrade is a very small individual aquatic invertebrates, and it has a closer relationship with arthropods, both as sister group. Tardigrade is concerned by the people with its unique phenomenon of the cryptic phenomena. Tardigrade can be divided into two distinct categories:Heterotardigrada and Eutardigrada by using the traditional morphological methods.Tardigrade have granular skin, sheet, spike-like, filamentous, and papillae attachments. The attachment according to their position in the annex can be divided into the head, side annex, on the back annex, annex dorsal and tail attachment (only a small number of marine species in existence). Annex to the side and back of the morphological taxonomy is important, especially for species of Heterotardigrada. Identification of some kind of tardigrades, we have to see the shape and surface structure of their eggs. Therefore, the species identification by using the traditional morphological methods is difficult, at present, a few researchers can identificate the specimens quickly and accurately. With the development of molecular biology techniques, a fast, accurate method for species identification-DNA barcoding technology get more and more people's attention.In this study,chloroform isoamyl alcohol extraction method was used to get several tardigrade's DNA, the PCR amplification and sequencing method are also used in this article.We successfully obtained the mitochondria DNA CO I sequence of six species just as Richtersius coronifer. In which five species have been uploaded to Genbank, and accession numbers are given in the text. By Comparing the mitochondria DNA COI nucleotides among the five tardigrades. we can see that Echiniscus wendti has the highest content of T, and the content of A+T is higher than the content of C+G is a common phenomenon in each species.In addition, analysis the system trees which were built by using adjacency method (NJ) and largest contracted method (MP), we can get that the mitochondria DNA COI bases of different individuals of the same species are very similar, and this situation was also appeared in different species of one genus. This result proved that it is feasibility to do the classification of tardigrade by using DNA bar code technology.This study is the first one in domestic study of DNA barcoding of tardigrade, because of the limited time and man power, only a few results were got. Tardigrade have about 1,000 recorded species currently, much more time, manpower and material resources are needed to get all of these species' DNA barcode. Currently there is specialized tardigrade genbank, the study of both bar coding and traditional morphological research of tardigrade will become the new trend in the word.