Study On Genetic Diversity Of Mitochondrial DNA Genome Of Yunling Cattle

Mitochondria are organelles that exist in the cytoplasm of eukaryotic cells.It has a set of genetic material similar to nuclear DNA,call mitochondrial DNA(mt DNA),which can independently replicate,transcribe,and translate.mt DNA has the characteristics of high mutation rate,non-recombination,maternal inheritance and other characteristics,and is a key tool for evaluating the origin,genetic diversity,phylogeny and population structure of livestock maternal lines.Yunling cattle is the first beef cattle breed in China that has been bred using a three-way cross.It combines 1/2 Brahman blood,1/4 Murray Grey blood,and1/4 Yunnan native blood lineage.Yunling cattle has strong environmental adaptability,strong resistance to rough feeding,strong resistance to internal and external parasites,and has the potential to produce snowflake beef.Evaluating the genetic characteristics of Yunling cattle and the origin of the maternal line is particularly important for the rational formulation of breeding strategies for Yunling cattle and the protection plan for Yunnan local cattle.In this study,129 Yunling cattle and 31 Brahman cattle ear tissue samples were collected,and the mitochondrial genome was sequenced using next-generation sequencing technology to discuss the genetic diversity of Yunling cattle and the origin of the maternal line.Below are key research findings:1.Based on mitochondrial genome analysis,47 different haplotypes were found in 129 Yunling cattle.The haplotype diversity is 0.964 ± 0.007,and the nucleotide diversity is0.00784 ± 0.00013,indicating that Yunling cattle have rich genetic diversity.2.Phylogenetic analysis results show that Yunling cattle have two maternal origins:ordinary cattle and zebu.The clustering shows that the mitochondria of Yunling cattle can be divided into seven haplotype groups: normal cattle T1,T2,T3,T4,T6 and tumor cattle I1,I2.Among them,the rumen I1 haplotype group accounted for the largest proportion(41.86%),followed by the ordinary bovine T3 haplotype group(28.68%).3.A new haplotype group T6 was found in Yunling cattle,which may be related to the complicated origin of Yunnan local cattle.This study systematically analyzes the genetic diversity and phylogenetic situation of the mitochondrial genome of Yunling Cattle,which helps to comprehensively understand the population structure and the origin of the maternal line of Yunling Cattle,and provides a theoretical basis for the evaluation and effective management of Yunling Cattle.Theconservation and utilization of genetic resources of local cattle also provide a certain scientific basis.