The Detection Of Diatom Population Diversity In Dianchi Lake By 18srDNA Clone Library And SEM

Objective:The distribution characteristics of diatoms in different areas of Dianchi Lake were detected by 18srDNA clone library and SEM,which was used for drowning identification in forensic science.Methods:We have designed diatom 18SrDNA primers by the Primer Primer 5 software based in diatom population of Dianchi Lake,and chosen 18srDNA specific primers A145F/Dia516R and universal primer 18sF/18sR from the literatures.diatom DNA was extracted from samples of Dianchi Lake using Power Soil DNA Isolation Kit,then amplified,cloned,sequenced by four pairs of primers respectively,and then compared their specificity and sensitivity.In the end,we obtained specific primer for diatom 18srDNA polymorphism test in Dianchi Lake.In Dianchi,we set up 6 collection points to collect water samples,extracted diatom DNA,then amplified by the primer which came from last step,constructed the 18srDNA clone library,clones were randomly selected and sequenced,the NCBI database sequence was applied to make compare and the right classification.Afterwards,We examined the diatom population in Dianchi Lake by SEM,compared the results of two detection methods,and compiled the SEM pattern of diatoms in Dianchi Lake.Results:(1)Power Soil DNA Isolation Kit can effectively extract diatom DNA in water samples,and the DNA have high purity and can be directly used for downstream applications.(2)The strongest specificity was 605F/605R,467F/467R and 18sF/18sR took the second and third,A145F/Dia516R was the last.605F/605R was the first about sensitivity,18sF/18sR caught the second,467F/467R and A145F/Dia516R were the weakest.(3)11 diatom genera,including Achnanthes,Melosira,Navicula,Nitzschia,Stephanodiscus,Cyclotella,Diatoma,Gomphonema,Rhoicosphenia,Fragilaria,Thalassiosira,were found in the samples by the method of 18srDNA clone library.(4)14 diatom genera,including Achnanthes,Melosira,Navicula,Nitzschia,Stephanodiscus,Cyclotella,Diatoma,Gomphonema,Rhoicosphenia,Fragilaria,Cymbella,Coconeis,Synedra,Tabellaria,were found in the samples by the method of SEM.Conclusion:(1)Power Soil DNA Isolation Kit can isolate diatom genomic DNA effectively,and the method of 18SrDNA clone library can be used in the analysis of water sample diatom population.It need to intensive study and explore about the method of 18srDNA clone library be used in the diagnosis of drowning in water.(2)The primer 605F/605R is suitable for alternative primer to examine diatom in Dianchi Lake.(3)15 diatom genera,including Achnanthes,Melosira,Navicula,Nitzschia,Stephanodiscus,Cyclotella,Diatoma,Gomphonema,Rhoicosphenia,Fragilaria,Cymbella,Coconeis,Synedra,Tabellaria,Thalassiosira,were found in the Dianchi Lake.There are certain differences in difference areas of Dianchi Lake.