Mini Muscle Lab Report

Introduction
This study approaches the understanding of the autosomal recessive “mini-muscle” phenotype in mice. Smaller body size and muscles as well as increased maximal oxygen intake are observed in mice with the “mini-muscle” phenotype. This observation raises an issue about why the selectively bred mice with the “mini-muscle” phenotype have reduced triceps and thigh muscle mass as they are able to cover greater distances; due to faster running speed, on an activity wheel compared to normal mice. However, greater exercise and load is thought to result in muscle hypertrophy.
Purpose
This study seeks to understand the adaptations and components that cause “mini-muscle” mice to have altered muscle structures and characteristics by observing
Also, the body mass in selected and control lines showed a positive correlation in relation to the mass of the tibialis. However in “mini-muscle” mice, body mass was negatively correlated with the mass of the tibialis. These results of mass indicate that the total body mass of the wheel exposed mice were less than that of the mice without wheel exposure. However, the “mini-muscle” mice showed lesser tibialis mass compared to both the wheel exposed and non-wheel exposed mice. In addition, results show that the “mini-muscle” mice showed the greatest hexokinase and citrate synthase enzyme activities than the selected and control group mice. The selected mice displayed greater hexokinase and citrate synthase enzyme activities than the control. Furthermore, the “mini-muscle” mice only showed the presence of type IIA+IID muscle fibers in tibialis whereas the selected and control group mice showed only about 60% of the muscle fibers in tibialis to be type IIA+IID. These results support the purpose of this study as noticeable changes and differences in muscle fiber type are observed in the “mini-muscle” mice compared to the normal wheel exposed and non-wheel exposed mice. The “mini-muscle” mice differed from the selected and control group mice in which there was an absence of type IIB fibers and an abundance of oxidative fibers. This factor contributes to the abilities of these mice to run longer distances than normal phenotype mice as the difference in selected and control groups are relative to enzyme