Understanding the Role of Epigenetics in Evolution

The DNA you inherit from your parents provides the blueprint for the person you are today. But did you know that chance events and your environment can cause subtle changes to the chemical makeup of your DNA? These chemical modifications affect how your genes work, and the study of this process is called epigenetics. It’s central to work being carried out at the University of Jyväskylä (JYU) by Dr Ilkka Kronholm, an Academy of Finland Research Fellow in the Department of Biological and Environmental Science. For several decades, researchers at JYU have strived to improve our understanding of the world around us, aiming to shape the future by solving global problems.

Ilkka is using fungal and yeast models to understand the role of epigenetics in evolution and in helping organisms adapt to their environment. He’s also examining the effect of genetic mutations, which are permanent alterations to the organism’s genetic code. This fundamental research could give clues at the molecular level as to how animals and plants cope with environmental changes, such as rising temperatures due to climate change. “We can sequence the genomes and see how many mutations occurred and what kind of mutations they are,” he explains. “We’re particularly interested in the properties of mutations and the mutation rate. We’re also looking at the epigenetic changes that have occurred and the rate of these changes.” The excellent laboratory infrastructure at JYU facilitates Ilkka’s high-quality research. This will soon be enhanced with new top-of-the-range equipment so his team can perform sequencing work in-house.  

Estimating the rate of epigenetic change can be quite challenging. Unlike genetic mutations, which are usually passed on to offspring, epigenetic modifications may fluctuate from generation to generation. Ilkka is working with collaborators in Germany who are developing statistical models to allow them to estimate the rate of epigenetic change more accurately. Networking and forging international collaborations to advance research are encouraged by JYU. One type of epigenetic change Ilkka’s team is examining is DNA methylation, where a methyl group is added to cytosine, one of the four building blocks that make up the DNA molecule. This can affect gene expression, that is, whether a gene is switched on or off. “You have to consider the possibility that an unmethylated base might change to a methylated state and then back again. So we have to account for that mathematically,” he says.

The burning question for many is, can epigenetic changes be passed from one generation to the next? Some people believe, for example, that offspring can inherit stress responses induced in the parents. If true, this could change the way we think about  heredity and evolution. There is solid evidence that epigenetic inheritance occurs in plants, and Ilkka’s group hopes to publish soon that it also occurs in filamentous fungi, Neurospora crassa. However, he urges caution when it comes to humans. “I don’t think there is very good evidence yet that these sort of methylation changes are inherited in humans,” he says. “We know that they change within the lifetime of a single person. But when human gametes are made, there is quite a bit of reprogramming in the germ cells, and that probably erases the majority of spontaneous methylation changes.”

Since arriving at JYU in 2014 after a postdoc in the UK, Ilkka has been very successful at attracting funding for his research from organisations like the Finnish Research Council and the EU. He comments that JYU recently provided valuable training to support EU grant applications. He enjoys living in Jyväskylä with all of the excellent opportunities for outdoor sport and recreation. And a short five-minute commute by bike to work means he doesn’t have to rely on a car every day. As a new parent, he also appreciates the excellent social supports available in Finland, where affordable childcare and excellent schooling are widely available. The university has an International Staff Services team to ensure that researchers and their families relocating from abroad are well looked after. There are also benefits to being part of the lively JYU community. “There’s a good atmosphere here in the department. Everybody is really friendly with each other,” he says. “And because there are so many students in Jyväskylä, there are always a lot of cultural things going on, quite a bit more than you would expect for a small city.”