Heredity of muscle fiber composition and correlated response of the
synergistic muscle in rats.
Suwa, Masataka, Tomohiro Nakamura, and Shigeru Katsuta.
Institute of Health and Sport Sciences, University of Tsukuba,
Tsukuba, Ibaraki 305, Japan, Department of General Education, Osaka
Institute of Technology, Asahi-ku, Osaka, 535, Japan
APStracts 3:0080R, 1996.
The extent to which muscle fiber composition was determined by genes
transmitted from parents, and the correlated response of the
synergistic muscle were analyzed by using successive selection of
rats. The foundation population (G0) was prepared by random choice
from heterogeneous stock produced by random-mating of three strains,
Wistar-Imamichi, Fischer 344 and Donryu. Selective mating for a high
percentage of fast twitch fiber (%FT) in the deep portion of the the
lateral head of the gastrocnemius muscle and random mating were made
from G0 to the seventh generation (G7). Successive selection caused a
significant increase (P < 0.05) of %FT in the gastrocnemius
muscle. The realized heritability for 7 generations was 0.29. %FT in
the soleus muscle of the selected line also increased (P <
0.05). In addition, significantly positive correlations (P <
0.05) were found between %FT in the gastrocnemius and soleus muscles
in G1-G7. We conclude that about 29% of the variation of %FT was
determined by genes transmitted from parents and %FT in the
gastrocnemius muscle was positively correlated with that of the
soleus muscle.
Received 7 August 1995; accepted in final form 26 February 1996.
APS Manuscript Number R496-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 20 March 96