Why Pigs 'Pig Out'
We are all familiar with the phrase “eat like a pig,” however it is uncommon to ponder the reason behind this display of gluttony we consider characteristic of pigs. Genetics has suggested that the reason behind this behaviour may lie in the genes. Geneticists have discovered that different forms of a particular gene can cause a pig to really pig out.
Various forms of a gene affecting appetite exist in pigs. One form produces leaner pigs that eat less and exhibit slower growth rates. A different form of the gene causes them to eat more and therefore grow faster and fatter. After studying the protein encoded by the malanocortin-4 receptor gene (MC4R) present in mammals, scientists discovered that altering a single amino acid subunit caused a significant variation in body fat. The replacement of the amino acid asparagine with aspartic acid produced pigs with 9% less backfat and a reduced growth rate. The suggested reason for this drastic difference is that the protein operates on the brain cells’ surface, affecting the pig’s appetite. The substitution of the single amino acid may alter the proteins capability of accepting incoming signals, thereby downgrading the hunger message.
This information can be utilized in the manipulation of economically important growth and performance traits in the pig. With the discovery of this hunger gene, genetic testing can offer a shortcut to selective breeding, giving direct information regarding the genes an animal carries and allowing farmers to identify whether a pig will make a real pig of itself.
By Zoe Sifonios
41300600
References:
Kim, S.K., Larsen, N., Short, T., Plastow, G., & Rothschild, M.F. A missense variant of the porcine melanocortin-4 receptor (MC4R) gene is associated with fatness, growth, and feed intake traits. Mamm Genome 11, 131-135 (February 2000).
Trived, B (2000) “Apetite Gene Suspected in Pigs” J. Craig Venter Institute
URL: http://www.genomenewsnetwork.org/articles/05_00/fat_gene.shtml
(date accessed: 27/5/07)
Various forms of a gene affecting appetite exist in pigs. One form produces leaner pigs that eat less and exhibit slower growth rates. A different form of the gene causes them to eat more and therefore grow faster and fatter. After studying the protein encoded by the malanocortin-4 receptor gene (MC4R) present in mammals, scientists discovered that altering a single amino acid subunit caused a significant variation in body fat. The replacement of the amino acid asparagine with aspartic acid produced pigs with 9% less backfat and a reduced growth rate. The suggested reason for this drastic difference is that the protein operates on the brain cells’ surface, affecting the pig’s appetite. The substitution of the single amino acid may alter the proteins capability of accepting incoming signals, thereby downgrading the hunger message.
This information can be utilized in the manipulation of economically important growth and performance traits in the pig. With the discovery of this hunger gene, genetic testing can offer a shortcut to selective breeding, giving direct information regarding the genes an animal carries and allowing farmers to identify whether a pig will make a real pig of itself.
By Zoe Sifonios
41300600
References:
Kim, S.K., Larsen, N., Short, T., Plastow, G., & Rothschild, M.F. A missense variant of the porcine melanocortin-4 receptor (MC4R) gene is associated with fatness, growth, and feed intake traits. Mamm Genome 11, 131-135 (February 2000).
Trived, B (2000) “Apetite Gene Suspected in Pigs” J. Craig Venter Institute
URL: http://www.genomenewsnetwork.org/articles/05_00/fat_gene.shtml
(date accessed: 27/5/07)
