Population Genetic Structure of Neoschoengastia Gallinarum in China Based on Mitochondrial DNA Markers
Abstract Background: Neoschoengastia gallinarum is a widespread agricultural pest in China.The larvae of N. gallinarum are parasitic on the body surface of poultry. Performance, carcass quality, and normal marketing of mite infected broilers are severely affected by pruritus and pockmark lesions on the body surface. In China, N. gallinarum research has primarily focused on occurrence regularity, biology, and control methods. The genetic structure, variation, and genetic relationship between the N. gallinarum populations in China are still unclear.Methods: Genetic variations and structure among populations of N. gallinarum was examined and analyzed based on the nucleotide sequences of a 1522 nt variable region of the mitochondrial tandem genes (COI, COII, and ND5) among 4 populations from 7 collection sites in southern China.Results: A total of 192 individuals in 4 populations were analyzed. The tandem genes sequences were aligned, and 75 haplotypes were detected, 4 of these shared between populations. The range of haplotype diversity was from 0.860 (FJ) to 0.978 (GX). The pairwise FST values among populations were higher (0.096-0.551).The haplotype network mediation map and phylogenetic tree showed that the haplotypes were divided into two clade, Which did not completely follow the distribution rule of geographical populations. The AMOVA result showed that the percentage of variation within populations (72.94%) was higher than that among populations (27.06%). Neutral test and mismatch analysisrevealed that N. gallinarum had not experienced an obvious population expansion in recent historical periods, and the population size was relatively stable.Conclusions: The N. gallinarum population showed high genetic diversity based on mitochondrial tandem genes analysis and strong ecological adaptability. Despite the fact that geogrphic isolation causes certain genetic differentiation among populations, N. gallinarum high gene flow among populations as a result of human trade activities, and there was no obvious geographical genetic structure.