Published online by Cambridge University Press: 14 April 2009
A pedigreed control strain was divided into three lines which were maintained genetically distinct over nine generations. Mean coefficients of inbreeding of about 0·1 were attained. Results suggest that discernible genetic drift had occurred in several traits. Separate estimates of genetic variance were obtained from observed variation between and within lines. These estimates differed significantly in the case of only one of the eight traits observed. Observed variation between lines agreed reasonably well with that predicted.