Callipyge gene in sheep
Double muscled sheep
What is Callipyge gene or "beautiful buttocks'
- CLPG phenotype is a single gene that is dominant when inherited from the sire.
- The occurrence of this phenotype is 50% when a heterozygous male is mated to a population of normal, noncarrier females.
- Mating heterozygous carrier females to normal noncarrier males results in 100% normal phenotype.
- When lambs from the latter matings are phenotyped, 50% carry the CLPG gene, which results in 50% CLPG expression in lambs produced from these males when mated to normal noncarrier females.
- This unique inheritance pattern has been termed "polar" overdominance.
Two big-bottomed sheep will have snake-hipped offspring. How the two mutants cancel each other out is still a mystery.
Performance traits of normal and callipyge rams, wethers, and ewes.
A is the normal carcass and B is callipyge gene lamb.
Implications of allowing the breed to proliferate within the Southdown breed
2. Discrimination against Southdowns for those who do not want the gene in their flocks.
3. Disqualification of Southdowns at stock shows that exhibit the gene.
4. Fraudulent representation of these animals by some breeders as normal, well- muscled sheep... duping uneducated buyers into purchasing a Callipyge carrier.
5. Increased disputes between buyer and seller from the sale of animals carrying the gene.
6. Promotion of a gene that could have a negative industry-wide implications
7. Potential for more difficulty during lambing.
8. Increased cost for genetic testing for the gene
9. Extreme difficulty in eliminating the gene for your herd once it has been introduced due to irregular inheritance pattern and lack of a commercial test.
Spread of the Callipyge gene
Red flags that may indicate that the gene may be present in an individual
2. Tendency to have a steep hip
3. Be wary of flocks that tend to have some lambs that are extreme in their muscle design with the other sheep in the same flock having average to below average amounts of muscle mass.
4. These sheep tend to be marketed in the wool and when they are less than 90 days old in order to mask some of the more extreme aspects of their muscle mass.
5. If you view a lamb and the muscle mass appears almost too much to be true, then be very suspicious that the lamb may be carrying the gene.
Diagnosis and control/ eradication of gene
American Sothdown Breeders Association. "News." American Southdown Breeders Association. American Southdown Breeders Association, 27 Apr. 2015. Web. 29 Apr. 2016. <http://southdownsheep.org/blog/2015/callipyge-gene>.
Gutknecht, Kurt, and Noelle Cockett. "Gene Marker Aids Livestock Production." EurekAlert! Utah State University, 12 July 1996. Web. 29 Apr. 2016.
Jackson, S.P., and J.R. Blanton, JR. "Review: The Callipyge Gene in Sheep." Professional Animal Scientist, n.d. Web. 29 Apr. 2016. <http://www.professionalanimalscientist.org/article/S1080-7446(15)31600-4/pdf>.
Jirtle, Randy L. "Geneimprint." : Press : 'Beautiful Buttocks' Pinned Down. Geneimprint, 15 Sept. 2002. Web. 29 Apr. 2016. <http://geneimprint.com/site/press/12368241-1154726026>.
Whitfield, John. "Mutation Gives Sheep Beautiful Buttocks." Nature.com. Nature Publishing Group, 17 Sept. 2002. Web. 29 Apr. 2016. <http://www.nature.com/news/2002/020917/full/news020916-3.html>.
Winstead, Edward R. "Genetic Mutation Explains beautiful Buttocks in Sheep." Genetic Mutation Explains beautiful Buttocks in Sheep. Genome News Network, 25 Oct. 2002. Web. 29 Apr. 2016. <http://www.genomenewsnetwork.org/articles/10_02/beautiful_buttocks.shtml>