Abstract
ABSTRACTContinuous reciprocal backcrossing results in individuals which are 67% heterozygous, and which, assuming a linear relationship between heterozygosity and heterosis, would be expected to exhibit 67% of the heterosis found in Fi hybrids. An experiment was undertaken to investigate this relationship in the reproductive traits of mice. By crossing and repeated backcrossing in both directions using two unrelated strains of outbred mice, females were produced which were 25, 50, 75 and 100% heterozygous. The crossbred females and the two purebred strains (922 females in all) were mated to a sire line of a genetically distinct strain to standardize foetal heterosis. The reproductive performance of females with different percentage heterozygosity gave estimates of maternal heterosis. A significant positive linear relationship was found between heterozy-gosity and heterosis in litter size, total weight of litter and individual weight of progeny both at birth and at weaning. The relevance of these results for livestock breeding is discussed.
Publisher
Cambridge University Press (CUP)
Subject
Animal Science and Zoology
Reference23 articles.
1. Touchberry R. W. 1978. The role of crossing dairy breeds in intensive milk production in temperate climates. In Proc. int. Symp. Optimum Methods of Cattle Breeding, Warsaw, pp. 107–140.
2. Eisen E. J. 1974. The laboratory mouse as a mammalian model for the genetics of growth. In Proc. 1st Wld Congr. Genetics Applied to Livestock Production. Madrid, pp. 467–492.
3. Relationships between exploratory behaviour and genic heterozygosity in the oldfield mouse
4. Economic efficiency of pig breeding schemes: A breeding company view
5. Cost-effectiveness and population structure in cattle breeding programmes
Cited by
23 articles.
订阅此论文施引文献
订阅此论文施引文献，注册后可以免费订阅5篇论文的施引文献，订阅后可以查看论文全部施引文献