Phylogeny Of Blaberidae Based On Transcriptome And Mitochondrial Genome

The family Blaberidae(Blattodea: Blaberoidea)with high species richness is worldwide distributed,and exhibits diverse geographic distribution,reproductive modes and habitats,which makes it as an important group in the field of biogeography and reproductive behavior.In recent years,there have been a number of studies on the phylogeny of Blaberidae based on mitochondrial genes and nuclear genes.However,due to the different gene markers used and the imbalance of representative samples in different studies,phylogenetic relationships within Blaberidae have not been clarified yet,and the non-monophyly of some subfamilies has not been well resolved.With the development of next-generation sequencing,transcriptome,which contains most of the orthologs that is suitable for phylogenetic analysis,has been widely used in recent phylogenies of insects and plants recently.Therefore,this study seeks to reconstruct the phylogenetic relationship of Blaberidae at the transcriptome level,and infer the divergence time of Blaberidae,as well as explore the role of different molecular data such as transcriptome,mitochondrial genome and nuclear gene data in the analysis of the phylogenetic relationship of Blaberidae.The transcriptome data of 15 Blaberidae species from 8 subfamilies were newly sequenced in this study.By combining the data obtained from our research team and NCBI,1830 orthologs and 129 loci were finally screened out,producing two transcriptome datasets containing 47 and 86 samples of Blaberidae,respectively(all subfamilies covered).Additionally,24 mitochondrial genome data were added to the existing mitochondrial genome data of Blaberidae,resulting in a total of 135 mitochondrial genome and nuclear gene datasets.In addition,to ensure consistent sampling and evaluate the analytical ability of different molecular data for the phylogenetic relationship of Blaberidae,the mitochondrial genome and nuclear gene datasets of 47 Blaberidae samples were selected.In conclusion,this study used IQ-Tree to construct phylogenetic trees of Blaberidae based on 6 datasets: Transcriptome dataset(Tr＿1),129 loci dataset(Tr＿2),mitochondrial complete dataset 1(Mt＿A1),mitochondrial complete dataset 2(Mt＿A2,with added nuclear gene markers to Mt＿A1),mitochondrial partial dataset 1(Mt＿P1,corresponding to Tr＿1),and mitochondrial partial dataset 2(Mt＿P2,with added nuclear gene markers to Mt＿P1).Main results are summarized as follows:1.The result of this study demonstrated that phylogenetic relationships of Blaberidae reconstructed based on transcriptome data and mitochondrial data were highly consistent on genus and species level.The topological relationship of subfamilies of Blaberidae was also in agreement among different transcriptome datasets with high support values.Furthermore,when nuclear genes(18S,28S)were incorporated into the mitochondrial genome,the phylogenetic result at the genus and species level were not significantly affected,with inconsistent topology and support values.2.The transcriptome data from Blaberidae revealed a distinct phylogenetic relationship: Oxyhaloinae +((Diplopterinae + Calolamprodes)+(((Gyninae +Panchlorinae)+(Blaberinae + Zetoborinae))+((Paranauphoetinae + Panesthiinae)+((Perisphaeriinae(Asiatica)+ Pycnoscelinae)+ Epilamprinae(Asiatica))))).This study highlighted the phylogenetic and biogeographic patterns of Blaberidae species,and revealed that the geographical distribution of some subfamilies agreed with the phylogenetic result.3.The result of this study supported the establishment of Calolamprodinae,Rhabdoblattellinae and Acutirhabdoblatta.It also supported the transference of Rhabdoblatta monticola to Opisthoplatia,and Lucihormetica from Blaberinae to Zetoborinae.4.In this study,transcriptome data(Tr＿1)and mitochondrial genome data(Mt＿P1)were used to infer the origin and divergence time of Blaberidae based on 8 fossil calibrations.The result showed that Blaberidae diverged from Blaberoidea during the Jurassic period(Tr＿1: 162.78 Ma;Mt＿P1: 178.8 Ma),suggesting that Blaberoidea experienced rapid evolution during the Cretaceous period,potentially due to the Cretaceous Terrestrial Revolution.Moreover,transcriptome data showed that subfamilies diverged during the Cretaceous period(Tr＿1: 73-110Ma),while mitochondrial genome data showed that the subfamilies diverged during the late Jurassic to the early Cretaceous period(Mt＿P1: 115-155Ma).