Genetic Analysis Of Apostichopus Japonicus Germplasm From China,south Korea And Russion And Biological Evolution Analysis Of Sea Cucumber From Deep Sea In Western Pacific Seamounts

Sea cucumber?Apostichopus japonicus?is an aquatic product with important economic value in echinoderms.It mainly distributes along the Bohai Sea and Yellow Sea in China.In recent years,sea cucumber industry has developed vigorously.China's aquaculture base has gradually expanded to the West and south.In the process of industrialization of sea cucumber cultivation,diseases,germplasm degradation,natural disasters,especially the autolysis of sea cucumber caused by high temperature in summer,seriously restrict the sustainable development of sea cucumber industry.Overfishing and environmental pollution led to a sharp decline in the number of wild spine parameters in natural sea areas,and the natural resources of wild sea cucumber tended to be exhausted.The sea cucumber has been listed as Endangered?EN?in the Red List of Endangered Species by the World Conservation Union?IUCN?.Therefore,investigating and studying the germplasm differences of wild sea cucumber in different areas is significance for protecting the genetic diversity of sea cucumber population,improving the breeding varieties of sea cucumber and promoting the healthy and efficient development of sea cucumber industry.In this paper,we will focus on the analysis of the genetic diversity of sea cucumber from Qingdao,Yantai,Russion and Korean Kunsan,Mokpo and Posco from the aspects of its apparent characteristics,quality,ossicle and genetic diversity?including SSR and mtDNA?.The deep-sea sea cucumber Y30071 obtained in the laboratory were used to study the deep-sea resources in order to better develop the deep-sea echinoderm resources.Using the cooperative platform of our laboratory and Ruizi company,we collected different month age cultured sea cucumber seedlings for ossicle research,which provided theoretical basis for determining the age of sea cucumber.1 Analysis of genetic diversity and population structure of sea cucumber in different geographical populations along the coasts of China,South Korea and RussionMorphological analysis showed that there were differences in color,weight,body length and number of spines among different populations of sea cucumber.The most significant difference was that Russion sea cucumber had the largest number of spines,More than 90%of the individuals contained six rows of spines.Korean Posco red sea cucumber had the longest and heaviest body,and its body color was red,which was different from the common color system of sea cucumber.The results of quality study showed that the peeling rate of Kunsan was the highest?85.78%?.The polysaccharide content of Posco yellow sea cucumber was the highest group,reaching 51.168 mg/g.Therefore,the quality indexes were different,and it was difficult to form a unified conclusion.In the study of ossicles,the results showed that there were four types of ossicles,all of which were distributed in 8 populations,but different populations of sea cucumber can be distinguished according to the existence of the shapes of plates in parapodia,tentacles and back body wall,as well as the existenc of the shaps of buttons in sucker,tentacles and abdominal body wall.In order to evaluate the genetic structure of sea cucumber populations with different body color characteristics in different sea areas,eight sea cucumber populations from China,Korea and Russion coastal areas were analyzed by using microsatellite and mitochondrial DNA methods,using PCR amplification technology and sequencing support.All 13 microsatellites were able to amplify 8 populations steadily,and 253 alleles,6.5 average effective alleles were detected in 8 populations.UPGMA cluster analysis of different groups showed that Qingdao,Yantai and Mokpo black Apostichopus japonicus were clustered into one group,while Russion,Posco yellow group,Kunsan black group and Posco black clustered into one group,then Posco red group in Korea was clustered into one group as an external group.mtDNA analysis showed that 16S rRNA gene was highly conservative and had low variation.COI and D-loop sequences were rich in genetic diversity.The COI gene was used to analyze the genetic differentiation of three body color sea cucumbers collected from Posco.The genetic differentiation coefficient F_st was less than 0.05,and there was no genetic differentiation.A phylogenetic tree based on COI gene was constructed for the collected population,the results showed that Qingdao and Yantai Apostichopus japonicus group were clustered into one group,then Korean Kunsan Apostichopus japonicus join this group and Korean Mokpo join it too.The outward order was Russian group and Korean Posco groups.Microsatellite cluster analysis and phylogenetic analysis of COI gene showed that the genetic structure an d differentiation of different populations of sea cucumber were not only related to geographical location,but also affected by ocean current and body color.2 Species identification and Germplasm analysis of important echinoderms in deep seaIn this study,we present the mitochondrial genome sequence and amplification analysis of COI gene of the sea cucumber?number Y30071?from Western Pacific Seamounts.This complete mitochondrial genome is 15920 bp in length and consists of 13 protein-coding genes,two ribosomal RNA genes and 22 transfer RNA genes.Most of these genes are coded on the H strand except for one protein-coding gene?nad6?and five tRNA genes which are coded on the L strand.In this study,we constructed the secondary structure maps of ribosomal RNA and transporting RNA in this sample,and 37 annotated genes in the mitochondrial genome was compared with that of 6 known species.The results showed that Y30071 was consistent with the gene arrangement of Apostichopus japonicus and Sea urchin,but different from Cucumaria miniata of Sea Cucumber.The phylogenetic tree showed that Y30071 and Synallactes sp.were clustered together,indicating that the sample belonged to Synallactidae and Synallactes.3.Difference analysis of ossicle morphology and composition in different month age stages of sea cucumberIn this study,ossicle morphology and species composition of sea cucumber at different months of age cultured in the same batch were studied.There were mainly table-shaped and rod-shaped bodies in sea cucumber at the age of 1 month.By the age of 6 months,the individuals of sea cucumber had adult morphology and all kinds of ossicles appeared.At the age of 10 months and 12 months,the table shape of sea cucumber ossicles was further improved.At the age of 20 months,the table shape had degenerated and the outer edge of table body chassis gradually became uneven from smooth circles.Among the tissues of sea cucumber,besides tentacles,the number of table-shaped bodies was the largest,accounting for 78%-94%.In the tentacles,the rod content was higher,accounting for 100%,19%,78%and 76%of the 6 months,10months,12 months and 20 months respectively.The distribution of the buttons shapes and plates shaps was less in all tissues,accounting for 0-17%and 0-8%respectively.At different age stages,the table body appears a certain degree of degradation,which is mainly manifested in the reduction of the number of holes in the chassis of the table body and the process of the outer edge becoming smooth from uneven,then gradually degenerating into rough and uneven circumference.The results will provide scientific data basis and theoretical basis for age determination of sea cucumber.