生物谷報道：能不能跑馬拉松很可能要看你的基因,。澳大利亞科學家一項最新的研究表明，基因變異可以廣泛地提升人類的肌肉耐力,。相關論文9月9日在線發(fā)表于《自然—遺傳學》上,。
人類有兩種類型的骨骼肌纖維,。一種是快纖維,，它不需要氧,，直接以糖類作為能源，主要參與需要極限力量和快速反應的運動,，比如短跑,。另一種是慢纖維，主要以有氧的方式參與需要耐力的運動,，比如馬拉松,。快纖維可以制造一種α輔肌動蛋白（ACTN3）,，它表明了機體產(chǎn)生快速力量的能力。已有研究證實,，從事耐力項目的運動員ACTN3基因的變異頻率比其他運動員更高,。
領導最新研究的是澳大利亞神經(jīng)肌肉研究所（Institute for Neuromuscular Research）的遺傳學家Kathryn North，她的小組深入研究了ACTN3基因如何影響小鼠的肌肉活力,。研究人員發(fā)現(xiàn),，缺乏ACTN3功能基因的小鼠會在快纖維中產(chǎn)生大量與有氧代謝相關的酶，且它們的濃度比正常小鼠要高得多,。此外,，在跑步測試中，變異鼠在精疲力竭之前的跑動距離也比正常鼠多33%,，這表明ACTN3基因的變異可以提升耐力,。
之前的研究表明，ACTN3基因在不同地域的人類中的變異頻率存在差異,，非洲平均為10%,，而歐洲和亞洲約為50%。為了進一步追溯該基因在人類中的進化歷史,，研究小組對共96位歐洲,、亞洲和非洲人的相關DNA片斷進行了測序。結(jié)果發(fā)現(xiàn),，ACTN3基因的可變性要高于其周圍的基因序列,，說明這是一個正向自然選擇過程。也就是說,，ACTN3基因變異一定賦予了現(xiàn)代人（6萬年前從非洲遷移到歐洲和亞洲）某種適應性優(yōu)勢,。
美國亞利桑那大學的遺傳學家Michael Nachmann認為，最新的研究是對ACTN3作用的一個極佳檢測，它支持了該基因變異會影響特定運動能力的結(jié)論,。巴西Paraná大學的進化生物學家Marcio Pie表示,，盡管North和同事沒有進一步推測ACTN3賦予的進化優(yōu)勢到底是什么，但這將是一個值得繼續(xù)探討的有趣問題,。（科學網(wǎng) 任霄鵬/編譯）
原始出處:
Nature Genetics
Published online: 9 September 2007 | doi:10.1038/ng2122
Loss of ACTN3 gene function alters mouse muscle metabolism and shows evidence of positive selection in humans
Daniel G MacArthur1,2, Jane T Seto1,2, Joanna M Raftery1, Kate G Quinlan1,2, Gavin A Huttley3, Jeff W Hook4, Frances A Lemckert4, Anthony J Kee5, Michael R Edwards6, Yemima Berman1, Edna C Hardeman5, Peter W Gunning2,4, Simon Easteal3, Nan Yang1 & Kathryn N North1,2
More than a billion humans worldwide are predicted to be completely deficient in the fast skeletal muscle fiber protein -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 -actinin-3 deficiency influences the function of fast muscle fibers. Here we show that loss of -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.
Institute for Neuromuscular Research, Children's Hospital at Westmead, Sydney, New South Wales 2145, Australia.
Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, Sydney, New South Wales 2006, Australia.
John Curtin School of Medical Research, The Australian National University, Canberra, Australian Capital Territory 0200, Australia.
Oncology Research Unit, Children's Hospital at Westmead, Sydney, New South Wales 2145, Australia.
Muscle Development Unit, Children's Medical Research Institute, Sydney, New South Wales 2145, Australia.
Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia.
Correspondence to: Kathryn N North1,2 e-mail: [email protected]
