Summary
The CH and IA inbred lines and crosses between them up to the S3 and sibbed backcross generations are used to analyse the genetic control of shank length and body conformation (1500 cocks and 1626 pullets) and egg weight in the autumn (854 pullets) and spring (670 hens).
Hatch effects are demonstrated for shank lengths and autumn egg weight. After adjustment for hatch effects, the genes controlling shank lengths and autumn egg weight are found to be associated with the genes for large size in the CH line. But association is less complete for spring egg weight, and such genes as might control the two derived measures of body conformation, an allometric index of plumpness and the modular difference between right and left shanks, show almost complete dispersion.
In the main analyses, by least squares equation of generation means to parameters for various genetic and maternal effects, the modular difference between shank lengths is not demonstrably heritable. Autumn egg weight shows only additive and dominant effects, the latter appearing more important. The remaining characters are best fitted by a model including interaction between pairs of linked loci. Maternal and sex-linked effects are shown for shank lengths. But shank lengths and plumpness in females are controlled primarily by duplicate gene interaction. In the less satisfactory analyses of spring egg weight and male plumpness, complementary gene interaction is indicated.
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Morton, J. Analysis of gene action in the control of body conformation and egg weight in the chicken. Heredity 33, 203–216 (1974). https://doi.org/10.1038/hdy.1974.87
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DOI: https://doi.org/10.1038/hdy.1974.87
