EST-SSR Marker Development Based On Artemia Transcriptome And Study Of Genetic Diversity Among Artemia Populations

In present study,170 novel simple sequence repeats(SSR)markers were identified from the obtained Unigene sequences of Artemia transcriptome library.Three geographic populations(Artemia parthenogenetica from Ebinur Lake,Artemia sinica from Yuncheng Lake and Artemia tibetiana from Shuanghu Lake)were used for marker screening,and 21 pairs of primers could amplify constant and legible expected DNA products.Finally,8 pairs of primers showed polymorphism through fluorescence labeling technique.The low number of microsatellite markers may be due to the low versatility of markers in three Artemia populations.The developed eight microsatellite loci were developed to characterize three Chinese Artemia geographical populations from different salt lakes.The results showed the number of alleles and number of effective alleles at each locus ranged 2 to 10 and 1.071 to 4.388,respectively.The averege expected and observed heterozygosity varied from 0.437 to 0.504 and from 0.592 to 0.640,respectively.The average polymorphism information content ranged from 0.370 to 0.432.These observations indicated that Yuncheng poluation has the highest genetic diversity,whereas Shuanghu population has the lowest.The genetic differentiation coefficient value indicated that the three populations are highly differentiated(Fst=0.333),this is related to the fact that the three Artemia populations belong to different species.Genetic identity analyses revealed that Yuncheng and Shuanghu population have the closest genetic relationship(0.429),and the cognate relationship between Yuncheng population and Ebinur population was the furthest.The possible reason is that Yuncheng and Shuanghu population belong to bisexual Artemia species and Ebinur Lake Artemia population belongs to parthenogenetic Artemia.Parthenogenetic Artemia from five lakes in central Asia(Kunlundinskoye,R4;Big Yarovoe,R6;Big Medvejie,R19;Seten,K6 and Aral,K25)were characterized genegtic diversity of five Artemia populations through 8 EST-SSR.The average polymorphism information content showed that 8 microsatellite loci in R4 and R6 populations were moderate polymorphism,while in other three groups were highly polymorphic.The number of alleles in the five populations ranged from 2 to 6,the effective alleles ranged from 1.516 to 4.205,the expected heterozygosity ranged from 0.34 to 0.77,and the Shannon index ranged from 0.612 to 1.568.The genetic diversity of K25 and R19 populations were the highest,which may be related to the high diversity of the population.The total genetic differentiation coefficient of the five populations was 0.132,indicating that the five populations were moderately differentiated.The Fst between R4 and R19 groups was the lowest(0.022),followed by R6 and R19(0.042),and the two groups with the highest Fst were R6 and K6(0.143),it may be related to their geographical location.Structure analysis showed that the genetic structures between R4 and R19 population were similar,the gene flow of two populations was widely.This study showed that microsatellite polymorphism loci based on the transcriptome of parthenogenetic Artemia can be used as a valuable tool for genetic diversity analysis.The results provide a basic understanding for Artemia resources of genegtic diversity and structure in some Chinese and central Asian salt lakes,which could establish a technology platform for the evaluation and sustainable utilization of Artemia resources in China and all over the world.