Study of hereditary trends in the shape of the murine mandible.
Inbred mice are a suitable material for genetic studies, and mandibular shape in particular provides a highly quantitative hereditary trait. We investigated which genetic trait in F1, F2 and N2 hybrid mice was most strongly affected by the presence of a large or small mandible in the parents. Ten C57BL/6By strain mice as parents with a small mandible and 10 MRL/n strain mice as parents with a large mandible were employed. Twenty-five (C57BL/6By male X MRL/n female) F1 and 67 F2 hybrids, and 28 (F1 male X C57BL/6By female) N2 backcross hybrids were obtained by laboratory mating. The inter-landmarks of the right mandible were measured by an electronic digitizer. Each mean value of horizontal dimensions in F1 mice resembled that in MRL/l mice, and that in N2 mice was intermediate between C57BL/6By and MRL/n mice. On the other hand, the mean values of vertical dimensions in F1, F2 and N2 hybrids were intermediate between those of C57BL/6By and MRL/n mice. Hence we suggest that horizontal dimensions are predominantly inherited by mice with a large mandible, and that vertical dimensions show intermediate inheritance between mice with large and small mandibles in the C57BL/6By and MRL/n strains.
Maeda
T
T
Department of Pedodontics, Nihon University School of Dentistry at Matsudo, Chiba, Japan.
Okamoto
K
K
Yoshida
A
A
Kurihara
Y
Y
D000818:Animals; D002508:Cephalometry; D004582:Electronics, Medical / Q000295:instrumentation; D005260:Female; D005823:Genetics; D008297:Male; D008334:Mandible / Q000033:anatomy & histology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation; D014716:Vertical Dimension