AN EXPERIMENTAL EVALUATION OF GENETIC CORRELATION

J. J. Rutledge ¹, E. J. Eisen ¹, and J. E. Legates ¹

¹ Department of Animal Science, North Carolina State University, Raleigh, North Carolina 27607

Heritability and genetic correlations realized from both single-trait and antagonistic index selection were compared with paternal half-sib estimates. Primary attention was focused on the genetic correlation between six-week body weight and six-week tail length. Parameters realized from single-trait selection were in excellent agreement with paternal half-sib estimates. However, the realized genetic correlation between six-week body weight and six-week tail length obtained from index selection was significantly greater than the other estimates. Differential inbreeding levels and realized selection intensities were considered and rejected as being causative factors for these results. Linkage disequilibrium probably was not a factor either, as the base population had been randomly mated and randomly selected with a large effective population size for many generations. It was concluded that with antagonistic index selection, the pleiotropic effects of genes may be more powerful in retarding response in aggregate genotype than current theory would suggest. Replication of all selected and control lines allowed the use of between-line estimators of sampling variances of realized genetic parameters in the above comparisons. Generally, standard errors of realized genetic parameters were much smaller than corresponding paternal half-sib standard errors. Thus, selection was an efficient method of estimation.

This article has been cited by other articles:

				K. M. Middleton, S. A. Kelly, and T. Garland Jr Selective breeding as a tool to probe skeletal response to high voluntary locomotor activity in mice Integr. Comp. Biol., September 1, 2008; 48(3): 394 - 410. [Abstract] [Full Text] [PDF]

				G. Davidowitz, D. A. Roff, and H. F. Nijhout A Physiological Perspective on the Response of Body Size and Development Time to Simultaneous Directional Selection Integr. Comp. Biol., June 1, 2005; 45(3): 525 - 531. [Abstract] [Full Text] [PDF]

				S. H. Rice Developmental Associations Between Traits: Covariance and Beyond Genetics, January 1, 2004; 166(1): 513 - 526. [Abstract] [Full Text] [PDF]

				F. A. Smith, J. L. Betancourt, and J. H. Brown Evolution of Body Size in the Woodrat over the Past 25,000 Years of Climate Change Science, December 22, 1995; 270(5244): 2012 - 2014. [Abstract] [PDF]

				D. Jablonski and D. JABLONSKI Heritability at the Species Level: Analysis of Geographic Ranges of Cretaceous Mollusks Science, October 16, 1987; 238(4825): 360 - 363. [Abstract] [PDF]