Can differential expression of genes contribute to variation in muscle mass?

In addition to locomotion, respiration and glucose homeostasis, skeletal muscle plays an important role in energy expenditure. Low muscle mass correlates with low energy expenditure and preponderance to obesity. Muscle mass can range between 19 and 50 kg in adult healthy males. Approximately half of this variation is determined by genes, whose identity is poorly understood. Intensity of expression of a gene can differ markedly among individuals leading to the differences in traits affected by that particular gene. Our study has implicated seven genes as potential modifiers of muscle mass in the mouse model. The aim is to examine if intensity of expression of these genes in the muscle is determined by innate genetic mechanisms which could affect muscle mass.