Genetic analysis of a divergent selection for resistance to Rous sarcomas in chickens.
Selection for disease resistance related traits is a tool of choice for evidencing and exploring genetic variability and studying underlying resistance mechanisms. In this framework, chickens originating from a base population, homozygote for the B19 major histocompatibility complex (MHC) were divergently selected for either progression or regression of tumors induced at 4 weeks of age by a SR-D strain of Rous sarcoma virus (RSV). The first generation of selection was based on a progeny test and subsequent selections were performed on full-sibs. Data of 18 generations including a total of 2010 birds measured were analyzed for the tumor profile index (TPI), a synthetic criterion of resistance derived from recording the volume of the tumors and mortality. Response to selection and heritability of TPI were estimated using a restricted maximum likelihood method with an animal model. Significant progress was shown in both directions: the lines differing significantly for TPI and mortality becoming null in the "regressor" line. Heritability of TPI was estimated as 0.49 +/- 0.05 and 0.53 +/- 0.06 within the progressor and regressor lines respectively, and 0.46 +/- 0.03 when estimated over lines. Preliminary results showed within the progressor line a possible association between one Rfp-Y type and the growth of tumors.
Pinard-van der Laan
Marie-Hélène
MH
UMR Génétique et diversité animales, Institut national de la recherche agronomique, 78352 Jouy-en-Josas, France. pinard@dga2.jouy.inra.fr
Soubieux
Denis
D
Mérat
Laurence
L
Bouret
Danièle
D
Luneau
Gillette
G
Dambrine
Ginette
G
Thoraval
Pierrick
P
D000818:Animals; D001358:Avian Sarcoma Viruses / Q000276:immunology*; D002645:Chickens / Q000235:genetics / Q000276:immunology / Q000821:virology*; D003627:Data Interpretation, Statistical; D007113:Immunity, Innate / Q000235:genetics* / Q000276:immunology; D016018:Least-Squares Analysis; D008285:Major Histocompatibility Complex / Q000235:genetics / Q000276:immunology; D010641:Phenotype; D001357:Sarcoma, Avian / Q000276:immunology*; D012641:Selection, Genetic