title: Impact of strong selection for the PrP major gene on genetic variability of four French sheep breeds(Open Access publication).
abstract: Effective selection on the PrP gene has been implemented since October 2001 in all French sheep breeds. After four years, the ARR "resistant" allele frequency increased by about 35% in young males. The aim of this study was to evaluate the impact of this strong selection on genetic variability. It is focussed on four French sheep breeds and based on the comparison of two groups of 94 animals within each breed: the first group of animals was born before the selection began, and the second, 3-4 years later. Genetic variability was assessed using genealogical and molecular data (29 microsatellite markers). The expected loss of genetic variability on the PrP gene was confirmed. Moreover, among the five markers located in the PrP region, only the three closest ones were affected. The evolution of the number of alleles, heterozygote deficiency within population, expected heterozygosity and the Reynolds distances agreed with the criteria from pedigree and pointed out that neutral genetic variability was not much affected. This trend depended on breed, i.e. on their initial states (population size, PrP frequencies) and on the selection strategies for improving scrapie resistance while carrying out selection for production traits.
authors.affiliation: INRA, UR631 Station d'Amélioration génétique des animaux, 31326 Castanet-Tolosan, France. isabelle.palhiere@toulouse.inra.fr
authors.forename: Isabelle
authors.initials: I
authors.lastname: Palhiere
authors.forename: Mickaeël
authors.initials: M
authors.lastname: Brochard
authors.forename: Katayoun
authors.initials: K
authors.lastname: Moazami-Goudarzi
authors.forename: Denis
authors.initials: D
authors.lastname: Laloeë
authors.forename: Yves
authors.initials: Y
authors.lastname: Amigues
authors.forename: Bertrand
authors.initials: B
authors.lastname: Bed'hom
authors.forename: Etienne
authors.initials: E
authors.lastname: Neuts
authors.forename: Cyril
authors.initials: C
authors.lastname: Leymarie
authors.forename: Thais
authors.initials: T
authors.lastname: Pantano
authors.forename: Edmond Paul
authors.initials: EP
authors.lastname: Cribiu
authors.forename: Bernard
authors.initials: B
authors.lastname: Bibé
authors.forename: Etienne
authors.initials: E
authors.lastname: Verrier
mesh_terms: D000818:Animals; D014644:Genetic Variation; D018895:Microsatellite Repeats; D008957:Models, Genetic; D010375:Pedigree; D011110:Polymorphism, Genetic; D018620:PrPSc Proteins / Q000235:genetics*; D012608:Scrapie / Q000235:genetics* / Q000517:prevention & control; D012641:Selection, Genetic; D034561:Sheep, Domestic / Q000235:genetics*
chemical_list: D018620:PrPSc Proteins