No I’m not talking about the Global Financial Crisis (for once), a study into recessive and semi-dominant genetic disorders has shown that they can be caused by interactions between multiple genes instead of a single mutation.
The first discovery linking biological abnormalities to genetics happened only two years after the discovery of Mendelian Genetics. Sir Archibald Garrod observed that alkaptonuria, a rare urinal disorder caused by high levels of amino acids tyrosine and phenylalanine, followed a recessive pattern in the families it was found in.
Scientists in Sydney University in 2004 identified that mutation of the gene SLC6A19 on chromosome 5 is responsible in Hartnup disorder, which has similar urinary effects. This autosomal recessive disorder affects the transport of amino acids such as leucine, valine, isoleucine, methionine and tryptophan in the tubules of the kidney and the lumen of the small intestine. The research was then widened to investigate other metabolic disorders iminoglycinuria (IG) and hyperglycinuria (HG) which also affected the amount of amino acid found in urine. It was expected that the research would yield a single gene responsible for the disorder once again.
The results however were completely the opposite, and multiple genes were found to contribute to the effect. Only one out of the seven families investigated corresponded to a monogenic pattern, displaying the huge complexity of the genes affecting the kidneys. Interactions between two or three genes were most common and some of the genes even retained partial function. Leading researcher, Professor John Rasko, says that these multiple gene interactions may in fact apply to many traits exhibiting Mendelian recessive or semi-dominant patterns. Once again research into the human genome has uncovered more intricate gene relationships.
Ekta Paw
s42037538
O’Neil, G. (22 April, 2009). Redundancy begets complexity. In Australian Life Scientist. Retrieved April 26, 2009 from
https://www.biotechnews.com.au/article/300292/redundancy_begets_complexity?pp=1&fp=4&fpid=1012
