Open Access

Genetic heterogeneity of residual variance in broiler chickens

  • Suzanne J Rowe1Email author,
  • Ian MS White1,
  • Santiago Avendaño2 and
  • William G Hill1
Genetics Selection Evolution200638:617

https://doi.org/10.1186/1297-9686-38-6-617

Received: 31 January 2006

Accepted: 9 June 2006

Published: 28 November 2006

Abstract

Aims were to estimate the extent of genetic heterogeneity in environmental variance. Data comprised 99 535 records of 35-day body weights from broiler chickens reared in a controlled environment. Residual variance within dam families was estimated using ASREML, after fitting fixed effects such as genetic groups and hatches, for each of 377 genetically contemporary sires with a large number of progeny (> 100 males or females each). Residual variance was computed separately for male and female offspring, and after correction for sampling, strong evidence for heterogeneity was found, the standard deviation between sires in within variance amounting to 15–18% of its mean. Reanalysis using log-transformed data gave similar results, and elimination of 2–3% of outlier data reduced the heterogeneity but it was still over 10%. The correlation between estimates for males and females was low, however. The correlation between sire effects on progeny mean and residual variance for body weight was small and negative (-0.1). Using a data set bigger than any yet presented and on a trait measurable in both sexes, this study has shown evidence for heterogeneity in the residual variance, which could not be explained by segregation of major genes unless very few determined the trait.

Keywords

broiler chickens body weight genetic variance environmental variance heterogeneity of variance

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Authors’ Affiliations

(1)
Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh
(2)
Aviagen Ltd., Newbridge

Copyright

© INRA, EDP Sciences 2006

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