关键词: 橘小实蝇, 线粒体基因组, 遗传多样性, 种群动态

Abstract:  【Aim】 Based on mitochondrial genome data, we aim to clarify the genetic diversity and genetic structure of the population of Bactrocera dorsalis in Yunnan Province, southwestern China, and reveal the dispersal routes of B. dorsalis in Yunnan, so as to provide the theoretical basis for the formulation and plan of the control strategy of B. dorsalis. 【Methods】 From July to September in 2022, we collected 15 geographical populations of B. dorsalis in Yunnan Province. The mitochondrial genomes were sequenced, assembled and annotated using the DNBSEQ-T7 platform. The genetic diversity and genetic differentiation were detected using MEGA-X 10.0.5, DnaSP 6.12 and Arlequin 3.5.2 software based on the sequences of 13 protein-coding genes (PCGs). The phylogenetic tree was constructed using maximum likelihood method and the haplotype network was constructed using PopART 4.8.4 software based on the sequences of 13 PCGs and COI. The historical dynamics of the populations were analyzed by neutrality test and mismatch distribution. 【Results】 A total of 149 complete mitochondrial genomes from 15 geographical populations of B. dorsalis in Yunnan were obtained， including 1 697 variable sites, showing a high level of genetic diversity (Pi=0.00783, K=87.591，Hd=0.9994). The genetic distance between the populations ranged from 0.00702 to 0.00874, and the genetic differentiation index was from -0.02345 to 0.05203. The phylogenetic tree and haplotype network did not show obvious population structure. The B. dorsalis population expansion occurred in Yunnan. The western and southern regions of Yunnan were the earliest invaded areas of B. dorsalis, while the northern region of Yunnan was one of the invaded areas later. 【Conclusion】 Different groups of B. dorsalis in Yunnan Province showed a high level of genetic diversity and weak genetic structure, and the mitochondrial genome variable sites were abundant and widely distributed in all populations. There was no obvious difference among these geographical populations. It is speculated that B. dorsalis spreads from the western and southern to the northern regions of Yunnan.

Key words: Bactrocera dorsalis, mitochondrial genome, genetic diversity, population dynamics