Revealing fine scale subpopulation structure in the Vietnamese H'Mong cattle breed for conservation purposes.

BACKGROUND: During the last decades, there has been an acceleration of the loss of domestic animal biodiversity. For conservation purposes, the genetic diversity of the H'Mong cattle, an indigenous local breed was studied. Single-nucleotide polymorphisms (SNP) of the SRY gene and mtDNA D-Loop sequence were analysed to clarify the origin of the breed. The genetic diversity was assessed through genetic data with twenty-five FAO microsatellites, and morphometric data with five body measurements from 408 animals sampled from eight districts of the Ha Giang province. RESULTS: The SRY genes were all of the zebu type. Among the 27 mtDNA haplotypes, 12 haplotypes were of the taurine type and the remaining 15 of the zebu type. This indicates female taurine introgression in the zebu H'Mong. The observed and expected heterozygosity ranged from 0.616 to 0.673 and from 0.681 to 0.729 respectively according to district, with low genetic differentiation (F ST = 0.0076). Multivariate analysis on morphometric and genetic data shows a separation of districts into two groups following a south-west/north-east cline and admixture analysis confirmed the two clusters, but no differentiation of taurine introgression between clusters was observed. A possible admixture with the Yellow cattle breed from a neighbouring province was suggested through genetic data and householder interviews. CONCLUSIONS: In this study we demonstrate the interest of fine-scale sampling for the study of genetic structure of local breeds. Such a study allows avoiding erroneous conservation policies and on the contrary, proposes measures for conserving and limiting crossbreeding between the H'Mong and the Yellow cattle breeds.

Genetic and morphometric characterization of a local Vietnamese swamp buffalo population.

The water buffalo plays a key role in the socio-economy of South-East Asia as it is the main draught power for paddy rice cultivation. While in the Indian subcontinent the water buffalo is the riverine type, in South-East Asia the majority of buffaloes are of the swamp type. In the poor remote northern province of Ha Giang in Vietnam, improvement of the swamp buffalo breed may be one of the best ways to increase sustainability of farming systems. Therefore, analysis of the genetic structure of the province buffalo population is a prerequisite to any conservation or improvement project. A total of 1122 animals were described for 11 body and horn measurements for morphometric characterization. From this sample set, 744 animals were genotyped for 17 microsatellite markers. Also 17 animals from southern provinces of Vietnam were genotyped as a comparative sample. The results showed that genetic diversity as well as inbreeding value in the Ha Giang was high. The F(ST) values within the province and across Vietnam were low indicating that most of the population variation is explained by individual variability. Bayesian clustering analysis did not highlight the presence of subdivided populations. These results are useful for the implementation of a conservation and improvement strategy of the swamp buffalo in order to guarantee the householders' needs for sustainability of the farming system in the Ha Giang province.