Maternal and sex-linked effects on size and conformation in domestic fowl

Analysis of gene action in the control of body conformation and egg weight in the chicken

“…The CH line dams increased shank length, significantly in females, and the CH line Z chromosome increased shank length, significantly in males, in which there was also marked homogametic heterosis. The first two of these results confirm the findings of Cock and Morton (1963), whose data included the S and S generations of the present analysis, but without separate analysis of the two sexes. Not only did the additive-dominance model fit the autumn 5-egg weights, but only the additive (d) and dominance (h) parameters reached significance.…”

“…The modular difference between the length of the right and left shanks was calculated as a possible measure of homeostasis of body form. And as an index of plumpness the allometric form of (body weight)/(mean shank length)25 was used (Cock and Morton, 1963). At 20 weeks of age pullets were selected to be placed in a battery house for the estimation of egg weights.…”

Analysis of gene action in the control of body weight and tail length in the mouse

“…In the rat Jinks and Broadhurst (1963) found that maternal effects were more important at 50 days of age than at weaning (21 days). In the chicken, where direct maternal influence ceases when the egg is laid, Cock and Morton (1963) found that none the less the pure-line maternal effect remained nearly constant, as a percentage of total body weight, throughout growth up to 20 weeks post-hatching. Thus the present results fit into a general pattern in which maternal effects on body size, far from ceasing with the break from the mother, persist at least throughout the acceleratory phase of growth.…”

Influence of sex chromosomes and maternal effects on production traits in the fowl

“…However, the reciprocal cross difference was not significant. Similarly Cock and Morton (1963) reported that the sex chromosome from the smaller of two lines used in reciprocal crosses in creased pullet weight by three percent.…”

“…Other sex-linked effects have been reported for egg shell color (Redman and Shoffner, 1961), yolk riboflavin (Collins £t £l,, 1970), hemoglobin content of the blood (Cock and Morton, 1963), Newcastle virus hemagglutination scores (Reta et al^., 1963), and histocompatibility (Bacon and Craig, 1967).…”