Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: The pattern of genetic and environmental variation in relation to ageing in laying hens | Genet Sei Evol 1992 24 265-275 Elsevier INRA 265 Original article The pattern of genetic and environmental variation in relation to ageing in laying hens G Engstrom LE Liljedahl M Wilhelmson K Johansson Swedish University of Agricultural Sciences Department of Animal Breeding and Genetics s - 750 07 Uppsala Sweden Received 12 June 1991 accepted 31 March 1992 Summary - Data from a selection experiment with laying hens were used to study the structure of genetic correlations as well as additive genetic and environmental variation over a period of 26-60 weeks of age. Genetic correlations were positive between all age periods for the 2 traits investigated egg number and egg weight. Thus the results do not support the pleiotropy theory of ageing which predicts negative genetic correlations between early and late fitness. For egg weight no trend with age was found for the 2 components of variance investigated. For egg number there was an increase in additive genetic variation as well as in environmental variation with age. The results support the mutation accumulation theory of ageing and other theories which postulate an increasing genetic variation with age. genetic variation environmental variation genetic correlation I age changes Resume Evolution avec 1 âge de la variance génétique et de la variance de milieu chez des poules pondeuses. Les résultats d une experience de selection de poules pondeuses ont été utilises pour étudier entre 26 et 60 semaines d age 1 évolution des correlations génétiques et des variances génétiques et de milieu. Les correlations génétiques entre differents ãges étaient positives pour les 2 caractères étudiés nombre d ceufs et poids des eeufs. Ces résultats ne confortent pas la théorie de pléiotropie du vieillissement qui prédit des correlations génétiques negatives entre differents ages. Pour le poids des ceufs aucune variation systématique avec 1 âge des deux variances n a été relevée. Pour le nombre d ceufs par contre les 2 variances .
