div class=ts-pagebuttonPage 1button div class=ts-image amp-img class=ts-thumb alt=Page 1: medical23andmecom · Muscle composition is influenced by a genetic marker in the ACTN3 gene ACTN3 The ACTN3 gene contains instructions for making alpha-actinin-3 a protein found src=https:reader034vdocumentsmxreader034viewer20220505025f9440fb76458a536f14f6a1html5thumbnails1jpg width=142 height=106 layout=responsive amp-img divdiv