Relationship Between Gene Expression Networks and Muscle Contractile Physiology Differences in Anolis Lizards

Area of Science:

• Comparative genomics and transcriptomics
• Molecular basis of muscle physiology
• Animal behavior and biomechanics

Background:

• Muscles enable diverse animal behaviors, requiring varied contractile properties.
• Sprinting demands rapid contractions, while biting requires greater force.
• Understanding molecular differences in muscle function is key to behavioral adaptation.

Purpose of the Study:

• To identify genes associated with variations in muscle contractile physiology.
• To compare gene expression between leg and jaw muscles in Anolis lizards.
• To correlate gene expression modules with specific muscle contractile metrics.

Main Methods:

• Transcriptomic sequencing of leg and jaw muscles from four Anolis lizard species.
• Measurement of muscle contractile physiology: Vmax, V40, power ratio, and twitch time.
• Weighted Gene Co-Expression Analysis (WGCNA) to cluster genes and correlate modules with physiological data.

Main Results:

• No significant species-specific gene expression differences were observed.
• Jaw and leg muscles differed significantly in twitch time, V40, and power ratio.
• Genes related to muscle contraction and extracellular matrix correlated with higher power and V40, while aerobic respiration genes correlated with slower twitch times.

Conclusions:

• Molecular mechanisms underlying muscle contractile variation can explain behavioral optimization.
• Differences in gene expression for muscle contraction, energy synthesis, and extracellular structures distinguish jaw and leg muscles.
• Aerobic respiration gene modules correlate with slower ATP utilization (slower twitch time), while muscle contraction and extracellular structure genes relate to force transmission.