Population structure and genetic variability of a closed Jaffarabadi buffalo herd from Brazil

Abstract

Small closed herds could have signifi cant negative genetic consequences including small effective size, inbreeding depression and the loss of diversity through genetic drift. Here we evaluate the population structure and genetic variability of a closed Jaffarabadi herd through careful analysis of the pedigree. The herd was characterized by a high generation interval (10.17±5.43 years), small effective population size (10) and very low effective number of ancestors (7) and founders (8). Four ancestors explained 50% of the genetic variability in the population and the most representative ancestor contributed approximately 33% of the population genetic variability. Estimated inbreeding was moderate with a value of 4.22%. However, this may be underestimated because of the shallow pedigree. Based on our results we strongly recommend the introduction of new reproductive individuals, with lowest possible average relatedness coeffi cients with the herd, to reduce the deleterious effects associated with inbreeding and low levels of genetic variability. Moreover, immediate action should be implemented to increase effective population size and to reduce the generation interval.