Application Study Of DNA Barcode And Fine Anatomic Technology In Identification Of Difficult Species In The Yangtze Estuary

The Yangtze River estuary is the largest estuarine ecosystem in China and the most important one in the world.Affected by the river and sea water,the physical and chemical properties of beaches and water bodies in the Yangtze River estuary are complex and changeable.Its complex ecological environment provides the conditions for the rich species diversity in the region,and the rich species resources also bring some challenges for the identification and classification of various species.The accurate identification and classification of species in this area is an important prerequisite for the study of biological resources,ecological environment science and estuarine ecological management,protection and utilization.DNA barcode and fine dissection technology can solve the problems that morphological classification technology is difficult to solve in some problem scenarios.Fine dissection technology based on high power optical microscope and scanning electron microscope can better display the internal morphological characteristics of species in the micro vision system that are difficult to find under the traditional morphological technology,and can provide important evidence of species Identification and bio-ecological analysis.It is of great significance to analyze and study the discovery,identification,revision and supplement of new species and records based on modern technology such as DNA barcode and fine anatomy,so as to clarify the taxonomic status of genera and species and the phylogenetic evolution process of various groups,which can provide basic information for production,scientific research,education,coastal ecological economic development and ecological research progress.Using DNA barcode and fine dissection technology can supplement the molecular identification data and morphological characteristics of the existing species with clear classification status;when it is difficult to deal with the problems only relying on the traditional morphological classification technology,using DNA barcode and fine dissection technology can accurately identify and classify the individual difficult species in a certain classification level;At the same time,DNA barcode and fine anatomy technology can be used to deal with a class of species identification classification and phylogenetic relationship analysis.Compared with traditional classification technology,it is more clear and thorough in species formation and evolution.In this study,we selected the species named after Shanghai area,Cyathura shanghaiensis,Assiminea sp.,which is the dominant species in the tidal flat of the Yangtze River estuary,but only identified to the Family,the difficult species of sulfates which are collected in the Yangtze River estuary and southeast coastal areas and the skeletal remains of cetaceans which are stranded in Shanghai waters but seriously polluted,which cannot be identified and classified according to the traditional morphological characteristics,for the application of DNA barcode and fine anatomy technology.It provides some basic data for the taxonomic identification and phylogenetic analysis of the species in the Yangtze River estuary.Through the research,the following progress has been made:1.In view of the important and difficult species of macrobenthic invertebrates in the Yangtze River Estuary,the DNA barcode data of cyathura shanghaiensis is supplemented,which provides the data basis for molecular identification of this species.On the one hand,it further consolidated the identification evidence of this species,and provided basic data for the taxonomic study of this genus.2.Assimina sp.is widely distributed in the Yangtze River Estuary and is an important dominant population in the intertidal zone.In this study,we used the universal primer sequence combined with the fine anatomy technology to supplement the description of the fine anatomy characteristics and DNA barcode data of Assimina sp.and identified it as Assimina grayana which was the first record in the Yangtze River estuary.It provides a direction for the artificial breeding,development and utilization of the species,and provides some basic data support for the related research and development and utilization.3.Onchidiidae is a large benthic invertebrate widely distributed in the Yangtze River estuary and southeast coastal areas of China,which has important scientific research and economic value.However,the taxonomic identification of Chinese Onchidiidae species has not been clear,the habitat condition is complex and the morphological characteristics are changeable so only relying on traditional taxonomy cannot carry out accurate taxonomic identification.In this study,we analyzed and identified several common difficult species of Onchidiidae in the Yangtze River estuary area and the southeast coastal area of China.The phylogenetic analysis and morphological difference of dentoglossus were completed by using DNA barcode and fine anatomy.This paper revised the conclusion that there are 5 genera and 6 species of Onchidiidae in China.It is believed that there are Platevindex sp.,Peronia verruculata,Platevindex mortoni,Onchidium reevesii,Onchidium stuxbergi,Paromoionchis tumidus,Wallaconchis graniferus and unknown species from Zhejiang Province in China.Among them,sample from Zhejiang Province is suspected to be new species.4.There are many kinds of whale activities or stranded records in the Yangtze River estuary.Based on the micro DNA barcode technology,this study completed the identification and analysis of a whale skeleton sample stranded in the Yangtze River estuary,and identified the sample accurately as Balaenoptera omurai,a new primer was provided for the first record of this species found in Shanghai waters,which was used to analyze the short target segments of whale DNA barcode.It also provided a certain data experience for the DNA extraction of the seriously polluted samples of difficult species and the primer design of the short target sequences of micro DNA barcode technology.