两种细蚤rDNA—ITS2序列的研究

SEQUENCES ANALYSIS OF RDNA-ITS2 OF TWO SPECIES IN GENUS LEPTOPSYLLA

本文首次测定和分析缓慢细蚤Leptopsylla segnis（Schonherr，1811）和距细蚤Leptopsylla lauta （Rothschild，1913）的rDNA—ITS2序列，为蚤的分类和系统发育研究提供有意义的基础资料。通过聚合酶链反应（Polymerase chain reaction，PCR）扩增缓慢细蚤L．segnis和距细蚤L．lauta各3个个体的rDNA．ITS2序列，并对扩增产物进行PCR直接测序和分析。结果显示，缓慢细蚤和距细蚤的rDNA．ITS2序列的长度均为309bp；缓慢细蚤序列的CG含量为50．9％～52．1％；距细蚤序列的CG含量为49．5％～50．6％。缓慢细蚤与距细蚤的rDNA—ITS2序列有16个碱基不同，其中7个是颠换，9个为转换，两种细蚤之间有一定差异。

To study the sequences of rDNA-ITS2 in Leptopsylla segnis （Schonherr, 1811 ） and Leptopsylla lauta （Rothschild, 1913） for providing basie information for the researches on siphonaptera phylogenesis. The rDNA-ITS2 sequences in the two species were amplified by PCR, and then sequenced directly and analyzed. The length of rDNA-ITS2 in both L. segnis and L. laura was 309 bp. The contents of base pair CG were 50. 9% -52. 1% in the rDNA-ITS2 sequence of L. segnis, and 49.5% -50. 6% in L. lauta. Sixteen base pairs in L. segnis were different from that in L. lauta, including 7 reverses and 9 conversions, implying a significant difference existed between the two Leptopsylla species.