According to http://www.genetic-future.com Approximately 70 percent of the Jamaican population contain a gene called α-actinin-3. α-actinin-3 is responsible for the explosive contraction of fast twitch muscle fibers, which muscle fiber is responsible for Highly intense short duration activities. There are two types of α-actinin-3, which are 577R and 577X. α-actinin-3 577R is the functional form of the gene whilst α-actinin-3 577X is the defective version of the gene and results in no muscle enhancing whatsoever. People who have both forms of the gene produce no α-actinin-3 in their fast twitch muscles at all. Research shows that at least 1/6 and 1/4 of the world’s population contain both forms of the gene.
Reference:
http://www.genetic-future.com/2008/08/gene-for-jamaican-sprinting-success-no.html (3/9/2009)
(Posted by Bennett Aue)
