Genetic relationship among lines and smooth muscle and ovarian follicular development within lines of Japanese quail in two long-term selection studies

Smooth muscle tumor and ovarian follicular development were studied in line s of Japanese quail selected for increased 4-wk BW (HW, P, and T) and their randombred controls (C and R1). The lines studied were from long-term sele ction studies at The Ohio State University (HW and R1) and The University o f Georgia (P, T,and C). To study the genetic relationship among the lines i n the two selection studies, the C, P, HW, and R1 lines were DNA-fingerprin ted by digestion of the DNA with the HaeIII restriction enzyme and using Je ffreys' 33.6 probe. The BW of females at 4 wk of age and at the end of a 240-d egg production p eriod were similar for the C and R1 lines. The BW of the selected lines was ranked P > T > HW for both measurements. Smooth muscle tumors were found i n the oviducal ligaments adjacent to the magnum. A greater percentage of he ns from the BW-selected lines had smooth muscle tumors of greater weight th an the randombred control lines, which did not differ in tumor incidence or weight. The P and T lines had a greater incidence of multiple-lobed tuners than the HW line. Based on bandsharing (BS) of DNA fingerprints, the Georg ia and Ohio lines did not appear to be closely related, suggesting that, pe rhaps, the smooth muscle tumors in the BW-selected lines in the two studies might have resulted from pleiotrophic effects of genes affecting growth or to genes closely linked to the growth genes. The BW-selected lines in both selection studies had more ovarian follicles in rapid development, which were of greater weight than the randombred cont rol lines. The HW line had a larger number of ovarian follicles in rapid de velopment than the P and T lines. The percentage of hens with atretic folli cles was greater in the BW-selected lines. The results of the present study suggest that the effect of BW selection on ovarian follicular development may occur early in selection (within the first 30 generations) and is not i nfluenced by additional genetic changes in BW.