Uncontrolled admixture and loss of genetic diversity in a local Vietnamese pig breed

Berthouly-Salazar Cécile, Thevenon Sophie, Thu Nhu Van, Trong Nguyen Binh, Pham Lan Doan, Vu Chi Cuong, Maillard Jean-Charles. 2012. Uncontrolled admixture and loss of genetic diversity in a local Vietnamese pig breed. Ecology and Evolution, 2 (5) : 962-975.

https://doi.org/10.1002/ece3.229

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Quartile : Q3, Sujet : ECOLOGY

Résumé : The expansion of intensive livestock production systems in developing countries has increased the introduction of highly productive exotic breeds facilitating indiscriminate crossbreeding with local breeds. In this study, we set out to investigate the genetic status of the Vietnamese Black H'mong pig breed by evaluating (1) genetic diversity and (2) introgression from exotic breeds. Two exotic breeds, namely Landrace and Yorkshire used for crossbreeding, and the H'mong pig population from Ha Giang (HG) province were investigated using microsatellite markers. Within the province, three phenotypes were observed: a White, a Spotted and a Black phenotype. Genetic differentiation between phenotypes was low (0.5-6.1%). The White phenotypes showed intermediate admixture values between exotic breeds and the Black HG population (0.53), indicating a crossbreed status. Management practices were used to predict the rate of private diversity loss due to exotic gene introgressions. After 60 generations, 100% of Black private alleles will be lost. This loss is accelerated if the admixture rate is increased but can be slowed down if the mortality rate (e.g., recruitment rate) is decreased. Our study showed that a large number of markers are needed for accurately identifying hybrid classes for closely related populations. While our estimate of admixture still seems underestimated, genetic erosion can occur very fast even through indiscriminate crossbreeding.

Mots-clés Agrovoc : porcin, variation génétique, race introduite, race indigène, ressource génétique animale, génétique des populations, conservation des ressources, amélioration des animaux

Mots-clés géographiques Agrovoc : Viet Nam

Classification Agris : L10 - Génétique et amélioration des animaux

Champ stratégique Cirad : Axe 1 (2005-2013) - Intensification écologique

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