Mitochondrial Genomes from Two Specialized Subfamilies of Reduviidae (Insecta: Hemiptera) Reveal Novel Gene Rearrangements of True Bugs

Abstract

Reduviidae, a hyper-diverse family, comprise 25 subfamilies with nearly 7000 species and include many natural enemies of crop pests and vectors of human disease. To date, 75 mitochondrial genomes (mitogenomes) of assassin bugs from only 11 subfamilies have been reported. The limited sampling of mitogenome at higher categories hinders a deep understanding of mitogenome evolution and reduviid phylogeny. In this study, the first mitogenomes of Holoptilinae (Ptilocnemus lemur) and Emesinae (Ischnobaenella hainana) were sequenced. Two novel gene orders were detected in the newly sequenced mitogenomes. Combined 421 heteropteran mitogenomes, we identified 21 different gene orders and six gene rearrangement units located in three gene blocks. Comparative analyses of the diversity of gene order for each unit reveal that the tRNA gene cluster trnI-trnQ-trnM is the hotspot of heteropteran gene rearrangement. Furthermore, combined analyses of the gene rearrangement richness of each unit and the whole mitogenome among heteropteran lineages confirm Reduviidae as a ‘hot-spot group’ of gene rearrangement in Heteroptera. The phylogenetic analyses corroborate the current view of phylogenetic relationships between basal groups of Reduviidae with high support values. Our study provides deeper insights into the evolution of mitochondrial gene arrangement in Heteroptera and the early divergence of reduviids.

Comparative mitogenomic analyses provide evolutionary insights into the retrolateral tibial apophysis clade (Araneae: Entelegynae)

“…The atp8 gene had the highest Ka / Ks value, consistent with the previously identified Ka / Ks ratios in spider species ( Kumar et al, 2020 ; Li et al, 2021 ), and insects ( Chakraborty et al, 2018 ; Li et al, 2019 ; Chang et al, 2020 ; Ye et al, 2021 ). It has been reported that different mitochondrial PCGs evolved at different rates ( Li et al, 2012 ; Zapelloni et al, 2021 ), as has been found in RTA species.…”

“…These ten RTA mitogenomes were biased toward A and T, consistent with previous findings ( Zhu et al, 2019 ; Li et al, 2020 ). Arthropod mitogenomes tend to have a positive AT-skew and a negative GC-skew on the J-strand, i.e., most species showed the strand asymmetry ( Wang et al, 2017 ; Ye et al, 2021 ). However, the strength of the skews in the mitogenomes of the RTA clade showed the opposite pattern, indicating that the J-strands of these mitogenomes have strand asymmetry reversal and favored T and G. This seemed to be a common phenomenon in Araneae ( Wang et al, 2016 ).…”

“…The atp8 gene in RTA mitogenomes may have experienced a positive selection in adaption to the environment. The cox1 had the lowest Ka/Ks ratio, as has been found in most of the arthropod mitogenomes (Chakraborty et al, 2018;Li et al, 2019;Ye et al, 2021), which represented fewer changes happened in amino acids and this gene was the most conserved one (Tyagi et al, 2017). Hence cox1 is widely used as a potential molecular marker for species identification and phylogenetic analysis.…”

Novel Mitochondrial Gene Rearrangement and Intergenic Regions Exist in the Mitochondrial Genomes from Four Newly Established Families of Praying Mantises (Insecta: Mantodea)

“…The gene arrangement of almost all insect mitogenomes is compact according to the ancestral phenotype, but exceptions have been detected in some orders, including Hymenoptera, Hemiptera, Ephemeroptera, and Mantodea, among others [ 28 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ]. Gene rearrangements are a relatively common phenomenon in insects, but gene duplications are rare [ 26 ].…”

Mitochondrial genome sequencing, mapping, and assembly benchmarking for Culicoides species (Diptera: Ceratopogonidae)

“…Despite gene content being preserved in most metazoans, gene arrangements and duplications can distinguish specific evolutionary lineages [ 6 ]. As gene rearrangements are generally uncommon within but vary among major lineages, their study allows for the resolution of taxonomic relationships using mitochondrial genome analysis (mitogenomics), unravelling complex evolutionary histories [ 6 , 8 ]. Fragments of the mitogenomes can also be transferred into the nuclear DNA, constituting nuclear mitochondrial DNA sequences (NUMTs).…”