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Maternal effects on weaning weight of mice

Lucia Galeão de Albuquerque; Roberto Gomes da Silva

Departamento de Melhoramento Genético Animal, FCAV - UNESP, 14870 Jaboticabal, SP, Brasil

ABSTRACT

The role of maternal effects on weaning weight was analysed in a population of mice under selection for this trait, with a total of 7042 records. Weaning weight was significantly affected by sex, class of litter size at birth, and generation number, together with linear and quadratic effects of dam inbreeding. Offspring inbreeding had no significant effect on weaning weight. Covariances among paternal half-sibs, full sibs, darn-offspring, and individuals with the same maternal grandsire were estimated by least squares. Covariances among relatives were taken as dependent variables, while the independent variables were the theoretical coefficients of causal components of genetic and environmental variances. Heritabilities of maternal and direct effects were obtained from the causal components, the coefficients being 0.286 and 0.275 respectively. However, the environmental component represented by littermates accounted for 41.83 percent of the phenotypic variance, constituting therefore, the main source of variation for weaning weight. The covariance between direct and maternal additive genetic effects was negative, and the respective correlation coefficient was -0.652. Total heritability of weaning weight was 0.079, i.e., less than the magnitude of heritability estimated from paternal half-sib correlations.

Keywords: Maternal effects; Weight of mice.

REFERENCES

Ahlschwede, W.T. and Robison, O.W. (1971). Prenatal and postnatal influences on growth and backfat in swine. J. Anim. Sci. 32: 10-16.

Blunn, C.T. (1969). Preweaning growth of cross-transferred rats. J. Anim. Sci. 28: 300-304.

Brandsch, H. and Kadry, A.E.H. (1977). The relative importance of prenatal and postnal maternal influences on growth in mice. Theor. Appl. Genet. 51: 119-125.

Cox, D.F., Legates, J.E. and Cockerham, C.C. (1959). Maternal influence on body weight. J. Anim. Sci. 18: 519-527.

Cundiff, L.V. (1972). The role of maternal effects in animal breeding: VIII. Comparative aspects of maternal effects. J. Anim. Sci. 35: 1335-1337.

Dickerson, G.E. (1947). Composition of hog carcasses as influenced by heritable differences in rate and economy of gain. Iowa Agr. Exp. Sta. Bul. 354: 489-524.

Eisen, E.J. (1967). Mating designs for estimating direct and maternal genetic variances and direct-maternal genetic covariances. Can. J. Genet. Cytol. 9: 13-22.

Eisen, E.J. (1974). The laboratory mouse as a mammalian model for the genetics of growth. In: 1st World Congress on Genetics Applied to Livestock Production, Editorial Garsi, Madrid, pp. 467-492.

Eisen, E.J., Legates, J.E. and Robison, O.W. (1970). Selection for 12-day litter weight in mice. Genetics 64:512-532.

El Oksh, H.A., Sutherland, T.M. and Williams, J.S. (1967). Prenatal and postnatal maternal influence on growth in mice. Genetics 57: 79-94.

Foulley, J.L. and Lefort, G. (1978). Méthods d'estimation des effects directs et maternels en sélection animale. Ann. Genet. Sel. Anim. 10: 475-496.

Hanrahan, J.P. and Eisen, E.J. (1974). Genetic variation in litter size and 12-day weight in mice and their relationships with post-weaning growth. Anim. Prod. 19: 13-23.

Harvey, W.R. (1960). Least-Squares analysis of data with unequal subclass numbers lth Ed. Agricultural Research Service, U.S. Department of Agriculture pp. 157.

Itulya, S., Ray, D.E. and Roubiceck, C.B. (1983). Maternal influence on growth of laboratory rats. J. Anim. Sci. 56: 330-335.

Koch, R.M. (1972). The role of maternal effects in animal breeding: VI. Maternal effects in beef cattle. J. Anim. Sci. 35: 1316-1323.

Legates, J.E. (1972). The role of maternal effects in animal breeding: IV. Maternal effects in laboratory species. J. Anim. Sci. 35: 1294-1302.

Robison, W.A. Jr., White, J.M. and Vinson, W.E. (1974). Selection for increased 12-day litter weight in mice. Theoret. Appl. Genet. 44: 337-344.

Rutledge, J.J. and Chapman, A.B. (1975). Systematic crossfostering within contro1 lines. J. Anim. Sci. 40:70-74. Rutledge, J.J., Robinson, O.W., Eisen, E.J. and Legates, J.E. (1972). Dynamics of genetic and maternal effects in mice. J. Anim. Sci. 35: 911-918.

Van Vleck, L.D. (1970). Index selection for direct and maternal genetic components of economic traits. Biometrics 26: 477-483.

Willham, R.L. (1963). The covariance between relatives for characters composed of components contributed by related individuals. Biometrics 19: 18-27.

Willham, R.L. (1972). The role of maternal effects in animal breeding. III. Biometrical aspects of maternal effects in animals. J. Anim. Sci. 35: 1288-1293.

Willham, R.L. (1980). Problems in estimating maternal effects. Livest. Prod. Sci. 7: 405-418.

Young, C.W., Legates, J.E. and Farthing, B.R. 91965). Prenatal and postnatal influences on growth, prolificacy and maternal performance in mice. Genetics 52: 553-561.