Over the years there has been discussion among scientists as to how much environment influences how an organism will behave, adapt or look. And while many scientist point to genes as the most important determining factor, Canadian scientists have recently increased the size of experimental ants by unlocking the mystery of how an animal’s environment affects how large they will become.
“It’s kind of making big news,” said Ehab Abouheif of McGill University’s evolutionary and developmental biology lab. Abouheif is also co-author of a paper published in Nature Communications.
Abouheif and other researchers observed ant colonies and asked the question; why are some ants of the same species large and others small? They found that their size seemed to depend on how much a single gene known as EGFR had been “coated” by a chemical process called methylation.
According to Abouheif, 70 percent of size differences between ants could be explained by how heavily methylated the gene was. The researchers turned the process around by manipulating the methylation of that one gene. They were able to grow ants twice as large as a normal ant.
“We used to think that traits like size that fall along a continuum were controlled by many, many, many genes, each having a small role, with the environment having a smoothing-out role,” said Abouheif. “What we’ve found is something quite fundamental . By putting a coat on a single gene, you can generate that whole continuum in size. You get this chemical coating on the gene that modifies the way the gene works. You don’t need any changes in the gene.”
Since methylation is influenced by outside factors such as food intake, Abouheif and his colleagues have not only defined exactly how environment works to control characteristics such as size, they’ve quantified the strength of that influence.
“What the food is doing is affecting these chemical modifications. What we’re showing is that genes and the environment are equal in their power to generate these continuous traits.