Mechanisms of adaptation in a predator-prey arms race: TTX-resistant sodium channels.
Populations of the garter snake Thamnophis sirtalis have evolved geographically variable resistance to tetrodotoxin (TTX) in a coevolutionary arms race with their toxic prey, newts of the genus Taricha. Here, we identify a physiological mechanism, the expression of TTX-resistant sodium channels in skeletal muscle, responsible for adaptive diversification in whole-animal resistance. Both individual and population differences in the ability of skeletal muscle fibers to function in the presence of TTX correlate closely with whole-animal measures of TTX resistance. Demonstration of individual variation in an essential physiological function responsible for the adaptive differences among populations is a step toward linking the selective consequences of coevolutionary interactions to geographic and phylogenetic patterns of diversity.
Department of Biology, Utah State University, Logan, UT 84322, USA.
Shana
S
Geffeney
Edmund D
ED
Brodie
Peter C
PC
Ruben
Edmund D
ED
Brodie
D000200:Action Potentials; D000222:Adaptation, Physiological; D000818:Animals; D005075:Biological Evolution; D017812:Colubridae / Q000502:physiology*; D004351:Drug Resistance; D016014:Linear Models; D008124:Locomotion / Q000187:drug effects; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000502:physiology; D018482:Muscle, Skeletal / Q000187:drug effects / Q000502:physiology*; D009469:Neuromuscular Junction / Q000187:drug effects / Q000502:physiology; D011235:Predatory Behavior; D012455:Salamandridae / Q000378:metabolism; D012867:Skin / Q000737:chemistry; D015222:Sodium Channels / Q000187:drug effects* / Q000502:physiology; D013779:Tetrodotoxin / Q000633:toxicity*; D014481:United States
D015222:Sodium Channels; D013779:Tetrodotoxin