Phylogenetic characterization of two common sandflies, Phlebotomus major and P. kandelakii, in Inebolu District of the West Black Sea Region, Türkiye based on mitochondrial gene sequence analysis

Abstract

Phlebotomus major and P. kandelakii are members of the Larroussius subgenus, which includes important vector sand fly species. Most members of the subgenus Larroussius have the ability to transmit Leishmania infantum, the causative agent of visceral leishmaniasis. Here, we investigated the genetic diversity within each species collected from the West Black Sea Region of Türkiye using mitochondrial DNA markers, specifically cytochrome oxidase I (COI) and cytochrome b gene sequences (Cytb). A total of 1889 sand fly specimens were collected from the study area in June 2021 and August 2022; 1596 (84.49%) were identified as P. major sensu lato, and 253 (13.40%) were identified as P. kandelakii. Nine and four haplotypes of P. major were determined in the study area based on COI and Cytb sequences, respectively. Analysis of the phylogenetic datasets generated from our isolates and published isolates in GenBank revealed high haplotype diversities within P. major (COI = 0.933, Cytb = 0.714). For P. kandelakii, we detected four and three haplotypes within the COI and Cytb sequences, and the haplotype diversities were also high in the datasets, including our isolates and published isolates in GenBank (COI = 0.978, Cytb = 1.000). Pairwise mean genetic distances calculated from the COI and Cytb datasets were 0.4% and 1.4% for P. major and 1.0% and 0.2% for P. kandelakii, respectively, suggesting the absence of cryptic species. Phylogenetic analyses revealed three and two major clusters of the Larroussius subgenus in the COI and Cytb datasets, respectively. Our study contributes to molecular information for P. major and P. kandelakii distributed in Türkiye and provides valuable insights into the phylogenetic relationships among species within the subgenus Larroussius