Analysis Of Population Genetic Diversity In Triplophysa Yarkandensis Based On Morphology And Microsatellite Markers

The purpose of this paper is to study the differences in the Triplophysa yarkandensis in the Tarim River Basin due to regional faults and analyze their genetic diversity.This research has completed three parts,the specific content is as follows:(1)Morphological biology of T.Yarkandensis in the lower reaches of Tarim RiverIn order to better protect the fishery resources of TarimRiver system,restoring the ecological balance of the Tarim River basin,the morphological biology of loach in three lower reaches of Tarim River was determined by classical biological method.The results showed that the body length range of T.Yarkandensis of Akesu River,Tainan River,Algan,Taitema lake and Che'erchen river was 69.23~137.51 mm,63.24~85.54 mm,56.71~78.61 mm,65.7~76.58 mm,58.78~65.26 mm.In terms of condition factor,the difference between Akesu River,Algan and Taitema lake was not significant(P> 0.05),while the difference between lake Tainan River and Che'erchen river was extremely significant(P< 0.01),and the Tainan River has a high degree of fullness.The groups of Aksu River,Algan and Lake Tetima decreased in turn,and the Che'erchen river had the lowest plumpness.The differences in eye distance/body length and eye distance/eyes interval between the five groups were very significant(P< 0.01);Differences in body height/body length,body width/body length between the Aksu River and the Tainan River,the Algan,Taitema Lake,and the Che'erchen River were very significant(P< 0.01);The cluster analysis showed that the Algan population and the Taitema Lake population were grouped into one group,the Aksu River population and the Tainan River population were grouped into one category,and the Che'erchen River population was separately grouped into one category.The results indicated that the morphology of the Tarim River showed anisotropy due to the long-term discontinuity of flow,although there are already signs of characteristic alienation among individuals,they have not yet reached the level of subspecies differentiation.The inability of communication between populations and the different living conditions caused by habitat fragmentation.Therefore,it is urgent to increase the ecological water flow of the Tarim River and protect fish resources.(2)Screening and analyzing of microsatellite loci of T.Yarkandensis based on the whole genome de novo sequencingThe study sequenced and synthesized 100 pairs of microsatellite primers with double and triple base repeat through high throughput sequencing in order to develop microsatellite markers of the populations of T.Yarkandensis in the Tarim River basin.Finally,33 pairs of primers with high polymorphism were selected.Polymorphism analysis was performed on 102 T.Yarkandensis using 33 pairs of primers obtained.The results showed that,the average allele and the effective allele were 43.848 and 12.163.The mean observed heterozygosity(Ho)and expected heterozygosity(He)were 0.239 and 0.902,respectively.The polymorphism information content(PIC)was 0.890.In the sequence of microsatellite,the more the base number,the less the repetition times,and with the increase of the base number,the corresponding number of microsatellite markers gradually decreased.The polymorphism index of SSR markers of dibasic repeat was significantly higher than that of trinucleotide repeat.(3)Isolation of microsatellite loci and genetic diversity analysis of T.YarkandensisIn order to study the genetic diversity of the five populations of loach in the T.Yarkandensis in the Tarim River,fifteen pairs of primers with high polymorphism were selected and amplified in the populationof loach in the T.Yarkandensis,in order to analyze its genetic diversity and population differentiation.The results showed that,The average alleles and effective alleles of the five populations of T.Yarkandensis were48.467 and 15.181,respectively.The observed heterozygosity(Ho)and expected heterozygosity(He)were0.578 and 0.929,respectively.The polymorphism information content(PIC)was 0.893,The index of gene differentiation(Fst)was 0.102.Among them that the alleles of Che'erchen were the most(18.143)and the alleles of Akesu River were the least(10.429).The observed heterozygosity of the Akesu River group was the highest(0.706),while the observed heterozygosity of the Taitema lake group was the lowest(0.517).The polymorphic information content of Algan population was the highest(0.877),while the polymorphic information content of Akesu River population was the lowest(0.760).The genetic distance between Akesu River and Tainan River population was the smallest(0.606),while the genetic distance between Algan river and Tainan River population was the largest(1.901).The genetic similarity between Algan population and Tainan River population was the least(0.149),while the genetic similarity between Akesu River population and Tainan River population was the greatest(0.545).The genetic structure of the population showed that the Che'erchen and Taitema lake,Akesu River and Tainan River,and Algan group gathered into one branch,and finally got together.The results showed that there were some differences among T.Yarkandensis in different reaches of Tarim River,but there was still gene exchange.