云南西花蓟马rDNA-ITS2遗传多态性及其种群扩张

Genetic diversity and population expansion in different geographic populations of Frankliniella occidentalis in Yunnan,China

应用rDNA-ITS2基因序列对云南各地理种群西花蓟马Frankliniella occidentalis(Pergande)的遗传结构和遗传分化程度进行初步研究。经过比对112条序列,共发现了59个变异位点,定义了30种单倍型。云南省西花蓟马的单倍型多态性较高(Hd=0.90219),而核酸多态性较低(Pi=0.00891)。各地理种群西花蓟马的遗传分化指数Fst为0.00810,基因流Nm为30.61,表明各地理种群间遗传分化程度非常低,种群间存在充分的基因交流。对群体进行中性检验、错配分析表明西花蓟马群体曾经历过近期的种群扩张。分子方差分析(AMOVA)表明,云南西花蓟马的遗传变异主要来自于种群内部,种群间的遗传变异水平还非常低。从分子生物学的角度上也证实了西花蓟马近期入侵云南的事实。

The rDNA-ITS2 gene was used to investigate genetic structure and differentiation among populations of Pergande,Frankliniella occidentalis（Pergande）,in Yunnan Province.112 rDNA-ITS2 sequences were analyzed,including 59 variable sites,defining 30 haplotypes.Haplotype diversity was quite high （Hd=0.90219） overall but nucleotide diversity was low （Pi=0.00891）.The Fst value was 0.00809 and gene flow was Nm=30.64 among all populations.These results suggest that genetic differentiation was low and that gene flow between different geographic populations was sufficient.Neutral test and mismatch analysis indicate that F.occidentalis has undergone a recent population expansion.The results of AMOVA also suggest that observed genetic differences mainly originate from inter-population differences,with relative little genetic variation within populations.These molecular data are consistent with the recent invasion of Yunnan by F.occidentalis.