China Animal Husbandry and Veterinary Medicine ›› 2020, Vol. 47 ›› Issue (1): 63-73.doi: 10.16431/j.cnki.1671-7236.2020.01.008

• Genetics and Breeding • Previous Articles     Next Articles

Genetic Diversity and Evolutionary Analysis of mtDNA D-loop Region in Jianchang Horse

ZHOU Fanli1, HUANG Weiping2, JIN Suyu1, YANG Shizhong2, HUANG Lin1, RAO Kaiqing1, ZHENG Yucai1   

  1. 1. Sichuan Provincial Key Laboratory of Conservation and Utilization of Animal Genetic Resources, Southwest Minzu University, Chengdu 610041, China;
    2. Sichuan Liangshan Prefecture Institute of Animal Science, Xichang 615042, China
  • Revised:2019-11-28 Online:2020-01-20 Published:2020-01-17

Abstract: In order to study the maternal genetic diversity and phylogenetic evolution of Jianchang horse using mitochondrial DNA (mtDNA),the genomic DNA was extracted from the blood of Jianchang horses (n=39),and the genetic diversity of mtDNA D-loop was assayed by PCR and direct sequencing.A 247 bp mtDNA D-loop hypervariable sequence was analyzed,the haplotypes and mutation sites of this region were assayed,and the haplotype diversity (Hd),nucleotide diversity (Pi) and average number of nucleotide differences (K) were calculated.The Neighbour-Joining (NJ) phylogenetic tree of 19 horse breeds including Jianchang horse was constructed,and the genetic distances among the breeds were calculated.The experiment obtained the PCR products with good resolution,and about 1 200 bp sequences were obtained by direct sequencing.The AT base content of the 247 bp mtDNA D-loop sequences from 39 samples (one of which lacked 1 bp) was 61.45%,with a characteristic of AT base pair enrichment region.26 unique haplotypes with 33 polymorphic sites were detected,and 4 of which were shared haplotypes,Hap7 and Hap1 were the dominant haplotypes.The Hd, Pi and K were 0.947,0.02399 and 5.901,respectively,indicating abundant maternal genetic diversity;The NJ phylogenetic tree demonstrated the presence of 6 major lineages (A,C,D,E,F and G),and about 50% were distributed in the A branch,indicating the complicated maternal origins of Jianchang horse.The genetic distance were the minimum (0.021) between Jianchang and Guanzhong horses,followed by Sanhe,Wenshan and Cheju horses (0.024),and the genetic distance with Jeju native horse was the maximum (0.032).In conclusion,the present study demonstrated that the mtDNA D-loop hypervariable region was rich in genetic diversity in Jianchang horse,showing multiple maternal origins,and the A branch had obvious advantages,which suggested that Jianchang,Guanzhong and Wenshan horses might have a common maternal origin.

Key words: Jianchang horse; mtDNA D-loop; genetic diversity; phylogenetic

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