58 GERMINATION.CA NOVEMBER 2018 CLASSICAL GENETICS HAS been with us for a long time, ever since Gregor Mendel put forward his laws on the basic mechanisms of heredity in the 19th century. Classical genetics has led to wondrous developments in the area of agriculture, including GM and gene editing tech- nologies. And now, another area of study is on the cusp of changing our ideas about plant function even more. Epigenetics, although it has existed as a concept for nearly eight decades, is becoming a new buzzword that is causing lots of chatter in plant breeding and seed circles, and for good reason. “Epigenetic technologies are on the cusp of being industry-ready. Unlike techniques such as CRISPR, it’s not quite there yet — but very close,” says Michiel Van Lookeren Campagne, head of seeds research at Syngenta. A field like epigenetics holds great promise for compa- nies like Syngenta, he says, which invests a lot of time and money in dealing with the regulatory hurdles that invariably come with breeding plants that have had their genetic codes altered in some way. Flipping Switches Epigenetics comes from the Greek root word epi, mean- ing “on” or “on top of.” “Epigenetics essentially sits on top of the layer of clas- sical genetics, which has been the basis of all breeding programs,” says Van Lookeren Campagne. Epigenetics is the study of heritable changes in gene function that do not involve changes in the DNA sequence. Epigenetic changes in plants do not occur as a result of any changes to the plant’s DNA, but as a result of other factors like changes to chromosomes that affect gene activity and expression. Basically, Van Lookeren Campagne explains, epige- netic changes occur when various “switches” in DNA are flipped on and off, triggering different reactions within the plant. He notes that epigenetics as a field really took off in the 1990s when Dutch and American molecular biologists breeding purple petunias obtained a number of unexpected results that were difficult to explain. They were trying to increase the colour intensity of the petals in petunias by introducing a gene inducing the formation of red pigment in the flowers. But instead of intensifying the colour, this treatment led to a com- plete loss of colour and the petals turned white. The mechanism causing these effects remained elusive until Andrew Z. Fire and Craig C. Mello discovered the cause, earning them the Nobel Prize in Physiology for Medicine for 2006. Fire and Mello deduced that double-stranded RNA can silence genes, that this RNA interference is specific for the gene whose code matches that of the injected RNA molecule, and that RNA interference can spread between cells and even be inherited. EXPLORINGTHENEXT FRONTIEROFGENETICS For researchers studying epigenetics, looking at the surface of the genome could be the key to discovering the next big thing in plant and seed engineering. Marc Zienkiewicz, Marc Airhart and Dana Yates Alberta’s Igor Kovalchuk has gained the reputation as a world leader in epigenetics. Photo courtesy University of Lethbridge