四川省不同流域日本沼虾群体遗传多样性分析

Genetic diversity of Macrobrachium nipponense populations in different river basins in Sichuan province

【目的】四川省河流众多,野生日本沼虾资源丰富,深入了解四川省日本沼虾种质资源现状,开展不同流域日本沼虾遗传多样性评估具有重要意义。【方法】基于线粒体Cytb序列,对四川省巴河(BH)、涪江(FJ)、嘉陵江(JLJ)、岷江(MJ)和思蒙河(SMH)5个日本沼虾野生群体的遗传多样性进行分析。【结果】所有群体的201尾日本沼虾中共检测出36种单倍型,单倍型多样性(H_(d))值为0.345~0.959,Hd均值为0.802,其中JLJ群体的Hd值最高(0.959),而MJ、SMH和BH群体的Hd值相对较低,H_(d)值均小于0.5。所有群体的核苷酸多样性(P_(i))值为0.00225~0.01547,P_(i)均值为0.01583,其中JLJ群体的P_(i)值最高(0.01547),BH群体的P_(i)值最低(0.00225)。日本沼虾的遗传变异主要来自群体间(68.20%),群体间存在显著的遗传分化,系统发育树分析显示所有群体呈现3个较明显分支。单倍型MJ网络图显示所有单倍型也呈现3个明显谱系,其中谱系A包含优势单倍型Hap 14,谱系B包含优势单倍型Hap 16,谱系C包含优势单倍型Hap 1。【结论】日本沼虾群体遗传多样性总体上处于较高水平,但不同流域的群体间遗传多样性水平差异较大,其中MJ、BH和SMH群体的遗传多样性相对较低,对这些流域内日本沼虾种质资源的保护有待进一步加强。本研究为四川省日本沼虾种质资源的保护与合理开发利用提供了参考依据,有利于促进四川省日本沼虾产业的可持续发展。

[Objective]Sichuan province has abundant rivers and rich resources of wild Macrobrachium nipponense.Understanding the genetic diversity of M.nipponense in dfferent river basins within Sichuan province is significant.[Method]In the present study,the genetic diversity of wild M.nipponense populations in the Bahe river(BH),Fujiang river(FJ),Jialingjiang river(JLJ),Minjiang river(MJ)and Simenghe river(SMH)in Sichuan province was analyzed based on the mitochondrial Cytb sequence.[Result]The study detected 36 haplotypes among 201 M.nipponense individuals from five populations.The average haplotype diversity(H_(d))for all populations ranged from 0.345 to 0.959,with an average H_(d) value of 0.802.The JLJ population had the highest H_(d) value(0.959),while the MJ,SMH and BH populations had relatively low H_(d) value,all of which were less than 0.5.The nucleotide diversity(P_(i))values of all populations ranged from 0.00225 to 0.01547,and the mean P_(i)value was 0.01583.The P,value of JLJ population was the highest(0.01547),and the P,value of BH population was the lowest(0.00225).The genetic variation of M.nipponense was mainly due to differences among populations(68.20%),indicating significant genetic differentiation.The phylogenetic tree analysis revealed three distinct branches among all populations.The MJ network map of haplotypes revealed that all haplotypes could be grouped into three distinct lineages.Lineage A contained the dominant haplotype Hap 14,lineage B contained the dominant haplotype Hap 16,and lineage C contained the dominant haplotype Hap 1.[Conclusion]The genetic diversity of M.nipponense populations is generally high,but varies greatly among different basins.The populations in MJ,BH and SMH have relatively low genetic diversity.Additional efforts are needed to enhance the conservation of the genetic resources of M.nipponense in MJ,BH and SMH.The study provides a reference basis for the conservation and sustainable development of wild M.nipponense,and is conducive to the sustainable development of aquaculture in Sichuan province.