Wendy is an average whippet in almost every way however she is sometimes compared to the hulk or Arnold Schwarzenegger all because of a mutation in her myostatin gene. The myostatin gene otherwise formerly known as Growth Differentiation Factor 8 (GDF-8) produces a myostatin protein which belongs to the TGF superfamily of proteins and acts as a growth factor that limits muscle tissue growth. Hence less myostatin within a body may cause an animal to become ‘double muscled’.
Wendy demonstrates a homozygous (two mutated copies of the gene) mutation in her myostatin gene however muscle hypertrophy has also been known to occur in heterozygotes (one mutated copy of the gene). Previous studies have demonstrated that heterozygotes represented a significant proportion of animals in the top racing classes, some animals reaching speed of 60km/hr; whereas homozygotes generally appear more muscular and are less able runners, this clearly demonstrating a competitive edge which breeders are now striving to exploit. Having these mutations do however have their negative effects, ‘bully whippets’ which double-muscled whippets are otherwise referred to, have double the muscle mass yet the same sized heart and lungs possibly resulting in a shorter life span, they are also prone to shoulder and thigh cramping.
This mutation in the myostatin gene has not yet been discovered in any other dog species yet has occurred in various species of cattle, humans and mice. There is hope that further research into the myostatin gene may lead to the development of therapies to muscular dystrophy.
Wendy demonstrates a homozygous (two mutated copies of the gene) mutation in her myostatin gene however muscle hypertrophy has also been known to occur in heterozygotes (one mutated copy of the gene). Previous studies have demonstrated that heterozygotes represented a significant proportion of animals in the top racing classes, some animals reaching speed of 60km/hr; whereas homozygotes generally appear more muscular and are less able runners, this clearly demonstrating a competitive edge which breeders are now striving to exploit. Having these mutations do however have their negative effects, ‘bully whippets’ which double-muscled whippets are otherwise referred to, have double the muscle mass yet the same sized heart and lungs possibly resulting in a shorter life span, they are also prone to shoulder and thigh cramping.
This mutation in the myostatin gene has not yet been discovered in any other dog species yet has occurred in various species of cattle, humans and mice. There is hope that further research into the myostatin gene may lead to the development of therapies to muscular dystrophy.
By Bianca Corstorphan
Primary Reference:
Lee, SJ 2007, ‘Sprinting without myostatin: a genetic determinant of athletic prowess’, Trends in Genetics, vol. 23, no.10, pp.475-477. Available at: http://www.sciencedirect.com.ezproxy.library.uq.edu.au/science?_ob=ArticleURL&_udi=B6TCY-4PPFT1K-1&_user=331728&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000016898&_version=1&_urlVersion=0&_userid=331728&md5=75a458bd64e23c7683762c68c48c6c52
Secondary References:
Westad, K 2007, ‘Big Wendy the muscular whippet’, Times Colonist, 25 June. Available at: http://www.canada.com/victoriatimescolonist/story.html?id=67f15c17-2717-4022-bb76-1b982456e793
Primary Reference:
Lee, SJ 2007, ‘Sprinting without myostatin: a genetic determinant of athletic prowess’, Trends in Genetics, vol. 23, no.10, pp.475-477. Available at: http://www.sciencedirect.com.ezproxy.library.uq.edu.au/science?_ob=ArticleURL&_udi=B6TCY-4PPFT1K-1&_user=331728&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000016898&_version=1&_urlVersion=0&_userid=331728&md5=75a458bd64e23c7683762c68c48c6c52
Secondary References:
Westad, K 2007, ‘Big Wendy the muscular whippet’, Times Colonist, 25 June. Available at: http://www.canada.com/victoriatimescolonist/story.html?id=67f15c17-2717-4022-bb76-1b982456e793
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