Genetic correlation between two types of nesting in Mus musculus: direct and indirect selection

The genetic correlation between maternal nesting (weight of cotton used in the nest built on the day of parturition) and thermoregulatory nesting (total weight of individual nests built on four consecutive days) was estimated from the correlated response of the former to selection for the latter. The best estimate was rA = 0.58 +/- 0.32, indicating a substantial amount of common genetic influence. Indirect selection seems to have produced a greater response in maternal nesting than could have been achieved by direct selection.