The Complete Mitochondrial DNA Sequence And Phylogenetic Analysis Of The Myodes Rutilus,Microtus Fortis,and Cricetulus Barabensis

The Circetidae,belonging to the order Rodentia,is also the most abundant family of rodent mammals,including 103 genera and 652 species.Hamsters are mainly concentrated in the low-and medium-dimensional areas of the Paleobec.The unique geographical conditions and arid monsoon climate endow this species with strong viability,so it is an ideal species for rodent origin.Mitochondria are typical semi-autonomous organelles in cells.They are characterized by a large number of gene copies,but a small genome and relatively conservative gene arrangement.Therefore,mitochondria are ideal materials for studying the phylogeny of species.In recent years,with the rapid development of molecular biology,the mitochondrial genomes of more and more species have been determined,and the work of determining the complete sequence of the mitochondrial genome of a species has become a hot topic.This study combines traditional morphology and phylogeny to determine the three species of Circetidae,Myodes rutilus,Microtus fortis,and Cricetulus barabensis.The entire mitochondrial genome sequence was annotated and analyzed.The measured mt DNA sequence was uploaded to the NCBI-Gen Bank sequence database.The sequence numbers were MK482363,MK805519,and MN056361,respectively.And downloaded the mt DNA of 22 species of Circetidae from the sequence library to combine with the measured 3 species,select the Sorex roboratus as the outgroup,and use the GTR+G+I model as the most suitable evolution model,Using the maximum likelihood method(ML)and the neighbor-joining method(NJ)for systematic evolution analysis.The main results obtained in this research are as follows:(1)Accumulate the 3 samples to be tested with the 36 species selected in Gen Bank,and select the Sorex roboratus as the outer group.The results showed that HB1 should be Myodes rutilus,DF1 should be Microtus fortis Pelliceus,HX1 should be Cricetulus barabensis,and the phylogenetic tree constructed by mitochondrial Cytb gene was consistent with the result of morphological identification.(2)The complete mitochondrial genomes of Myodes rutilus,Microtus fortis Pelliceus,and Cricetulus barabensis were determined.The complete mitochondrial genomes of the three Circetidae species are double-stranded ring-packed molecules,with full lengths of 16296 bp,16310 bp,and 16282 bp,And each contains 13 protein coding genes,2 r RNA genes,22 t RNA genes,1 L chain replication origin and 1 DLoop control region;The gene arrangement and transcription direction of the three species are similar to those of other Circetidae species.(3)The A+T% content of the whole mitochondrial genome of the Myodes rutilus,Microtus fortis Pelliceus,and Cricetulus barabensis are 59.8%,59.9%,and62.4%,respectively,and the base composition has a certain A/T bias Sex.(4)In the use of the start codon of the protein encoding gene,except for ND1,ND2,ND3,and ND5 with special GTG,AT T and ATA,the rest have ATG as the start codon;the stop codon is used On the other hand,the stop codons of the Myodes rutilus and Microtus fortis Pelliceus have incomplete monodeoxynucleotides(T--or TA-),while the stop codons of Cricetulus barabensis only have incomplete monodeoxynucleotides(T--),the rest are typical stop codon TAA.(5)The r RNA sequences of the mitochondrial genomes of the Myodes rutilus,the Microtus fortis Pelliceus,and the Cricetulus barabensis are relatively conservative;except for t RNA-Ser,the remaining 21 t RNAs belong to the typical clover structure;the length of 12 s RNA is 949 bp,950 bp,and 954 bp;the length of16 s RNA is 1516 bp,1563 bp,and 1561 bp;the length of t RNA is 59-75 bp.The length of the D-Loop region is 948 bp,921bp,and 885 bp,and they all contain three structures: the extended end associated sequence(ETAS)domain,the central conserved domain(CD)and the conserved sequence block(CSB)domain.(6)Using Cytb gene sequence and mt DNA full gene sequence,using ML and NJ methods to construct a phylogenetic relationship consistent with the information shown in the genetic distance table.Among the three species studied,Myodes rutilus is closely related to the Microtus fortis Pelliceus.Among the 25 selected species of the Circetidae species,the genetic relationship between Myodes rutilus and Myodes glareolus is the closest,and the genetic relationship with Allocricetulus eversmanni is the furthest;the Microtus fortis Pelliceus and the same species The named Microtus fortis fortis and the Microtus fortis calamorum are closely related,in addition to Microtus kikuchii,and the most distant from the Allocricetulus eversmanni;The Cricetulus barabensis is the closest to the Cricetulus griseus,and the farthest to the Microtus cabrerae.