RESUMO
In the Junggar Basin plague focus, Rhombomys opimus and Meriones meridianus live together, and their parasitic fleas have a similar community structure. However, R. opimus has significantly higher positive rates of Yersinia pestis and anti-F1 antibody compared with M. meridianus. In this study, Y. pestis- and antiF1 antibody-negative R. opimus and M. penicilliger were collected in Qitai county, Fukang city and Mulei county of the eastern part of the Junggar Basin. The genomic DNA was extracted from their spleen tissues, and RT1-Db1*exon1 was amplified through PCR procedure and then sequenced. Sequence analysis was performed and molecular diversity parameters were calculated and compared. The results showed that there were significant differences in nucleotide composition, amino acid composition, number and distribution of single nucleotide polymorphism (SNP) sites and number of haplotypes between R. opimus and M. penicilliger. The nucleotide diversity (π) for R. opimus was 0.00420 ± 0.00139, the haplotype diversity (h) was 0.833 ± 0.086, and the average number of nucleotide differences (K) was 2.02564. The π for M. penicilliger was 0.06569 ± 0.02524, and the h was 1.000 ± 0.045, and the K was 10.4444. The fixation index (FST) value between R. opimus and M. penicilliger was 0.9207. Furthermore, the FST value within R. opimus (0.0275) was significantly lower than that within M. penicilliger (0.2106), indicating a greater genetic variation of M. penicilliger compared with R. opimus. In conclusion, the genetic diversity analysis based on RT1-Db1*exon1 showed that M. penicilliger had higher gene polymorphism and greater genetic differentiation compared with R. opimus in the Junggar Basin plague focus, which might be associated with the low infection rate of Y. pestis.
