Estimates of heritability of response to Rous sarcomas of chickens.

The stocks used for this investigation consisted of 1039 F3 generation progeny from the cross of two highly inbred lines and 355 and 462 offspring from subpopulations UNH 105A and UNH 105B, respectively, of a noninbred line of New Hampshires. Matings were such that B complex alleles were segregated in the three experimental populations with minor exceptions. Each chicken was inoculated at 6 weeks of age with a subgroup of Rous sarcoma virus (RSV). Resulting tumors were subjectively scored on a scale from 0 (no tumor) to 6 (massive tumor) six times during a 10-week experimental period. Based upon the six tumor scores, each chicken was then assigned a tumor profile index (TPI), a criterion of antitumor response. The TPI were analyzed by least squares analysis of variance and corrected for hatch, sex, and virus prior to obtaining components of variance and estimates of heritability from a nested analysis of variance. Estimates of heritability from the sire component ranged from 0 to .41 +/- .27 and from the dam component .18 +/- .09 to .26 +/- .14, which are rather low estimates in general.