QTL analysis of type I and Type IIA fibers in soleus muscle in a cross between LG/J and SM/J mouse strains
- 1 School of Medical Sciences, College of Life Sciences and Medicine, University of Aberdeen, Aberdeen, UK
- 2 Department of Human Genetics, The University of Chicago, Chicago, IL, USA
- 3 Department of Psychiatry and Behavioral Neuroscience, The University of Chicago, Chicago, IL, USA
Properties of muscle fibers, i.e., their type, number and size, are important determinants of functional characteristics of skeletal muscle, and of the quality of meat in livestock. Genetic factors play an important role in determining variation in fiber properties, however, specific genes remain largely elusive. We examined histological properties of soleus muscle fibers in two strains of mice exhibiting a twofold difference in muscle mass, LG/J and SM/J, and their F2 intercross. The total number of muscle fibers (555 ± 106; mean ± SD) did not differ between the strains or between males and females. A higher percentage of type I fibers was observed in the LG/J compared to the SM/J strain (P < 0.001) in both males (45 ± 3 vs. 37 ± 4%) and females (58 ± 4 vs. 41 ± 3%). Across strains, females had a higher percentage of type I fibers than males (P < 0.001), and the sex effect was greater in the LG/J strain (strain-by-sex interaction, P < 0.001). The cross-sectional area (CSA) did not differ between type I and type IIA fibers, but was greater in the LG/J than the SM/J strain (1365 ± 268 vs. 825 ± 229 μm2, P < 0.001). Three significant quantitative trait locus (QTL) affecting CSA for type I and type IIA fibers mapped to chromosomes (Chr) 1, 6, and 11 and three suggestive QTL for percentage of type I fibers mapped to Chr 2, 3, and 4. Within each significant QTL, regions of conserved synteny were also implicated in variation of similar traits in an analogous study in pigs. Our results provide the evidence that the intercross between the SM/J and LG/J strains is a promising model to search for genes affecting muscle fiber properties.
Keywords: skeletal muscle, muscle fiber types, genetic variation
Citation: Carroll AM, Palmer AA and Lionikas A (2012) QTL analysis of type I and Type IIA fibers in soleus muscle in a cross between LG/J and SM/J mouse strains. Front. Gene. 2:99. doi: 10.3389/fgene.2011.00099
Received: 01 October 2011; Paper pending published: 01 November 2011;
Accepted: 08 December 2011; Published online: 06 January 2012.
Edited by:
Rongling Wu, Pennsylvania State University, USA
Copyright: © 2012 Carroll, Palmer and Lionikas. This is an open-access article distributed under the terms of the Creative Commons Attribution Non Commercial License, which permits non-commercial use, distribution, and reproduction in other forums, provided the original authors and source are credited.
*Correspondence: Arimantas Lionikas, School of Medical Sciences, University of Aberdeen, Health Sciences Building, Room 106, Foresterhill, Aberdeen AB25 2ZD, UK. e-mail: a.lionikas@abdn.ac.uk