Identification of host animals for plague by DNA barcoding in the epidemic focus of Lasiopodomys brandti

Abstract

Objective To study the feasibility of DNA barcoding in identification of host animals with plague.Methods Seven species were collected,including Lasiopodomys brandti,Spermophilus dauricus,Ochotona daurica,Phodopus campbelli,Allactaga sibirica,Meriones unguiculatus and Rhombomys opimus in the epidemic focus of Lasiopodomys brandti,Inner Mongolia,China.Liver was extracted and mitochondrial cytochrome oxidase subunit Ⅰ gene （CO Ⅰ） was analyzed.The GC content and genetic distance by Kimura-2-parameter（K2P） were calculated using MEGA5.0,and the phylogenetic trees were constructed with Neighbor-Joining （NJ） method.Results Sixty-one CO Ⅰ gene sequence fragments were barcoded,and each sequence was 657 bp in length.The GC% of A llactaga sibirica,Lasiopodomys brandti,Meriones unguiculatus,Ochotona daurica,Phodopus campbelli,Rhombomys opimus and Spermophilus dauricus were （46.945 ± 0.109）%,（43.836 ± 0.000）%,（40.313 ± 0.084）%,（47.514 ± 0.073）%,（41.838 ± 0.073）%,（40.335 ± 0.000）% and （39.467 ± 0.032）%,respectively,and the differences between them were significant（all P 〈 0.05）,except the difference between Rhombomys opimus and Meriones unguicalatus（P 〉 0.05）.The 1st codon GC contents of the seven species were （57.534 ± 0.000）%,（55.251 ± 0.000）%,（54.338 ± 0.000）%,（57.078 ± 0.000）%,（55.308 ± 0.057）%,（53.881 ± 0.000）% and （56.164 ± 0.000）%,respectively,and the differences between them were significant （all P 〈 0.05）,except the difference between Lasiopodomys brandti and Phodopus campbelli （P 〉 0.05）; the 3rd codon GC content of the seven species were （40.835 ± 0.328）%,（33.790 ± 0.000）%,（24.136 ± 0.253）%,（43.455± 0.218）%,（27.740 ± 0.207）%,（24.201 ± 0.000）% and （19.772 ± 0.097）%,respectively,and the differences were significant （all P 〈 0.05） among species,except the difference between Rhombomys opimus and Meriones unguicalatus （P 〉 0.05）.The average intraspecific genetic distance （K2P） was 0.003 and the average interspecific genetic distance was 0.234 8.A NJ tree showed 7 major clusters.Conclusion CO Ⅰ sequencing of DNA barcoding can be used to identify host animals with plague in the epidemic focus of Losiopodomys brandti,and can provide stronger evidences in identification of species based on morphology. Key words: DNA barcoding; CO Ⅰ gene; Plague