Loss of ACTN3 gene function alters mouse muscle metabolism and shows evidence of positive selection in humans.
More than a billion humans worldwide are predicted to be completely deficient in the fast skeletal muscle fiber protein alpha-actinin-3 owing to homozygosity for a premature stop codon polymorphism, R577X, in the ACTN3 gene. The R577X polymorphism is associated with elite athlete status and human muscle performance, suggesting that alpha-actinin-3 deficiency influences the function of fast muscle fibers. Here we show that loss of alpha-actinin-3 expression in a knockout mouse model results in a shift in muscle metabolism toward the more efficient aerobic pathway and an increase in intrinsic endurance performance. In addition, we demonstrate that the genomic region surrounding the 577X null allele shows low levels of genetic variation and recombination in individuals of European and East Asian descent, consistent with strong, recent positive selection. We propose that the 577X allele has been positively selected in some human populations owing to its effect on skeletal muscle metabolism.
MacArthur
Daniel G
DG
Institute for Neuromuscular Research, Children's Hospital at Westmead, Sydney, New South Wales 2145, Australia.
Seto
Jane T
JT
Raftery
Joanna M
JM
Quinlan
Kate G
KG
Huttley
Gavin A
GA
Hook
Jeff W
JW
Lemckert
Frances A
FA
Kee
Anthony J
AJ
Edwards
Michael R
MR
Berman
Yemima
Y
Hardeman
Edna C
EC
Gunning
Peter W
PW
Easteal
Simon
S
Yang
Nan
N
North
Kathryn N
KN
D000185:Actinin / Q000235:genetics* / Q000502:physiology; D000483:Alleles; D000818:Animals; D044466:Asian People; D014644:Genetic Variation; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D018345:Mice, Knockout; D023421:Models, Animal; D008957:Models, Genetic; D018482:Muscle, Skeletal / Q000378:metabolism*; D010807:Physical Endurance / Q000235:genetics; D011110:Polymorphism, Genetic; D012641:Selection, Genetic; D044465:White People