Table 5.

$H_{RI\overline{x}}^2$ (heritability accounting for repeated sampling of the same genome) estimates for quantitative ultrasonic vocalization traits in the BXD family, measured on postnatal days 7, 8, and 9.

Phenotypes	Postnatal day	$H_{RI\overline{x}}^2$
Number of calls	7	0.7
Number of calls	8	0.77
Number of calls	9	0.55
Duration of calls	7	0.84
Duration of calls	8	0.88
Duration of calls	9	0.74
Frequency of calls	7	0.75
Frequency of calls	8	0.65
Frequency of calls	9	0.63
Amplitude of calls	7	0.82
Amplitude of calls	8	0.89
Amplitude of calls	9	0.78

Up to 315 animals were used each day, from the 41 BXD strains, B6, D2, B6D2F1, and D2B6F1.