THE SEQUENCE BETWEEN MITOCHONDRIAL NAD1-NAD2 GENES ARE POTENTIAL MOLECULAR MARKERS OF HARPACTORINAE PREDATORS (HETEROPTERA: REDUVIIDAE)

Abstract

Assassin bugs are terrestrial predators belonging to the family Reduviidae. Among the 24 subfamilies, harparctorinae is predominant and extensively investigated for biocontrol applications compared to the others subfamilies in Reduviidae. Being natural enemies of phytophagous insects, understanding the phylogeny of these predatory bugs can precise the selection of candidates to employ in insect pest management. In addition to morphological systematics, complete mitochondrial genome sequences provide great insights into the phylogeny for resolving evolutionary complexity. Complete mitochondrial genomes of four potential predatory harpactorinae and one outgroup triatominae were retrieved from NCBI GenBank database. Comparative analysis of the five mitogenomes and the nucleotide sequence between nad1 and nad2 genes were selected as the best option to distinguish. The nucleotide sequence between nad1- nad2 are found to be biased towards A and T similar to their respective complete mitogenomes. Tajima’s test of neutrality suggest that the evolutionary selection at nad1-nad2 was parallel to the complete mitogenome and showed positive and significant (p > 0.1) with high nucleotide diversity. Unequal evolutionary rate at nad1-nad2 between lineages observed in Tajima’s relative rate test and proved the nucleotide sequences of nad1-nad2 between species are highly variable. Comparing the phylogenetic trees generated using the complete mitogenomes and nad1-nad2 genes uncovered the correlation between the trees and having identical branches with varying bootstrap values. Conventionally the highly conserved protein-coding cox1 gene is used for molecular taxonomy whereas this study provides an additional and/or a possible alternative molecular marker for genetic comparative test (the nucleotide sequence between nad1-nad2) to understand the systematics and phylogeny of Reduviidae. The significant nucleotide diversity, high genetic distance and less genetic similarity of the sequence between nad1-nad2 genes among the species studied, Agriosphodrus dohrni, Rhynocoris fuscipes, Scipinia horrida, and Velinus nodipes undoubtedly propose the possible utilization of nad1-nad2 region as distinguishable molecular marker.