Epigenetics: Are Darwin’​s Theories About To Evolve?

Detail of an epigenome.
Detail of an epigenome.
Markus C. Schulte von Drach

MUNICH â€" The field of epigenetics is being lauded for its discoveries, which some describe as revolutionary. There’s talk of a wide range of scientific textbooks being rewritten. But are the findings really that groundbreaking?

First, what is epigenetics? It is any additional information that gets tacked on top of the genome. Epigenetics refer to changes in genetic activity that don't change the DNA itself. Among the field's potential wide-ranging effects are the ways that experience of an animal or human affects its offspring, even if those experiences took place before the offspring’s conception.

One study found that the grandchildren of women who had been pregnant during the Dutch famine of 1944 were, on average, fatter than their peers. The experience of the grandmothers had apparently had an impact on two generations after them.

Last year, scientists from Mount Sinai Hospital in New York reported that the children of Holocaust survivors were more likely than others to suffer from problems like post-traumatic stress. In other words, trauma could be passed from one generation to the next.

What’s really spectacular about these results is that they question the basic principles of Charles Darwin’s theory of evolution, which says, in a nutshell: Organisms develop certain characteristics based on their genes. Mutation allows the offspring to develop modified or new characteristics, which are then passed on to the next generation. If such a modification proves to be useful, these genes would become more widespread in a given population.

But with the recent findings, an idea that has been around for a long time but was considered outdated has now resurfaced, that is, Lamarckism from the 19th century. A classic example of giraffes illustrates the idea: The long necks of the animals apparently developed by stretching towards leaves on high trees. Their slightly stretched neck then had been passed on to their children, whose necks then stretched further, and so on.

These findings redefine parental responsibility. Now we have to ask ourselves how much our children really have to suffer from our behavior, whether it’s an unhealthy diet or a lack of physical activity.

But along with enthusiasm about these findings, there’s also criticism about the interpretation of these scientific studies. It has been clear for a long time that in specialized body cells specific genes can be activated, and this process can, in theory, be "passed on" to the cells of female offspring. The impact of a person’s diet and other environmental factors on genes has long been evident.

What’s new and actually exciting is the observation that epigenetics affects the genetic material in egg cells and sperm, which can then be passed on to offspring. Epigenetically active molecules are being removed from the DNA in these cells so that all different kinds of specialized cells can be redesigned in the embryo.

Scientists have known for a while that that's exactly what happens with some species of plants and animals through environmental factors. "It’s wrong to assume that during the development, the whole genome is being cleaned," says Isabelle Mansuy, professor for neuro-epigenetics in Zurich. "Some genes’ epigenetic profile will be erased, others will not." The concept of reprogramming has wrongly been generalized.

Scientists don’t expect any significant medical findings from the epigenetic research so far. According to the American geneticist, John Greally, most studies that are looking for causes of illness in the epigenome "are suffering from significant problems when it comes to their design as well as conduct, which is strongly affecting their interpretability." Moreover, molecular biologist Steven Henikoff from Seattle can’t imagine "a way to define at all what is really nature, and what’s environmentally determined, without experiments on humans, which are, per se, forbidden."

Mansuy, on the other hand, stresses the importance of epigenetics when it comes to understanding and treating diseases. "The epigenetic inheritance is an extremely important phenomenon." According to her, it’s also vital for evolution because it allows for quick adaptation to environment. In the long run, modifications of the genome might even be necessary.

"But even a few epigenetic adjustments can be stable and permanent. And there’s a theory that says that epigenetic alterations can also lead to genetic alterations and can thereby contribute to classic evolution," she says.

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Feed The Future

COP26 Should Mark A Turning Point In Solving The Climate Crisis

Slow Food calls for an action plan to significantly reduce and improve the production and consumption of meat, dairy, and eggs by 2050.

A new dawn?

If, as the saying goes, we are what we eat, the same also goes for the animals that end up on our plate. How we feed our own food can have knock-on effects, not just for our own health but also for the planet. We are now aware of the meat and dairy industry's significant carbon footprint, responsible for more than a third of global anthropogenic greenhouse gas emissions.

Large-scale cattle productions that favor pure profit over more sustainable practices also add to environmental woes through biodiversity loss, deforestation and pesticide use — with some of the world's richest countries contributing disproportionately: The five biggest meat and milk producers emit the same amount of greenhouse gases as the oil giant Exxon.

The good news is that we could meet — if we would — some of these challenges with an array of innovative solutions, as the fields of farming, breeding and nutrition look at ways to shift from centralized intensive agro industry toward a more localized, smaller-scale and more organic approach to production.

Cows fed corn and grain-based diets may grow larger and are ready to be processed at a younger age — but this requires significant energy, as well as land and water resources; in contrast, grass and hay-fed cows support a regenerative farming model in which grazing can contribute to restoring the health of soil through increased microbial diversity. Compared to highly processed GM crops, natural-grass diets with minimal cereals also lead to more nutrient-rich livestock, producing better quality meat, milk and cheese. Farmers have started focusing on breeding native animal species that are best adapted to local environmental contexts.

This new approach to agricultural practices is closely linked to the concept of agroecology, where farming works in tandem with the environment instead of exploiting it. If mowed a few times a year, for instance, natural meadows produce hay that is rich in grasses, legumes and flowers of the sunflower family, like daisies, dandelions, thistles and cornflowers. These biomes become reservoirs of biodiversity for our countryside, hosting countless species of vegetables, insects and birds, many of which are at risk of extinction. Until recently, these were common habitats in meadows that were not plugged or tilled and only required light fertilization. Today, however, they are becoming increasingly threatened: in the plains, where the terrain is used for monocultures like corn; or in hills and mountains, where fields are facing gradual abandonment.

It is worth noting that extensive agriculture, which requires smaller amounts of capital and labor in relation to the size of farmed land, can actually help curb climate change effects through carbon dioxide absorption. Researchers at the University of California, Davis determined that in their state, grasslands and rangelands have actually acted as more resilient carbon sinks than forests in recent years. Through a system of carbon uptake, these lands provide a form of natural compensation, going as far as canceling the farms' impact on the planet, rendering them carbon "creditors."

In the meantime, grasslands and pastures allow animals to live in accordance with their natural behavioral needs, spending most of the year outside being raised by bonafide farmers who care about animal welfare. A recent study by Nature found that allowing cows to graze out of doors has both psychological and physical health benefits, as they seem to enjoy the open space and ability to lie on the soft ground.

Some might worry about the economic losses that come with this slower and smaller business model, but there are also opportunities for creativity in diversifying activities, like agro-tourism and direct sales that can actually increase a farm's profit margin. This form of sustainable production goes hand-in-hand with the Slow Meat campaign, which encourages people to reduce their meat consumption while buying better quality, sustainable meat.

Others may assume that the only environmentally-conscious diet is entirely plant-based. That is indeed a valuable and viable option, but there are also thoughtful ways to consume meat in moderation — and more sustainably. It also should be noted that many fruits and vegetables have surprisingly large carbon footprints: The industrial-scale cultivation of avocados, for example, requires massive amounts of water and causes great hardship to farming communities in Latin America.

But forging a broad shift toward more "biodiversity-friendly" pastoralism requires action by both those producing and eating meat, and those with the legislative power to enact industry-wide change. It is urgent that policies be put into place to support a return to long-established agricultural practices that can sustainably feed future generations. Although no country in the world today has a defined strategy to decrease consumption while transforming production, governments are bound to play a key role in the green transition, present and future.

In Europe, Slow Food recommends that the Fit for 55 package include reducing emissions from agriculture activities by 65% (based on 2005 levels) by 2050. Agriculture-related land use emissions should also reach net-zero by 2040 and become a sink of -150 Mt CO2eq by 2050. But these targets can only be met if the EU farming sector adopts agroecological practices at a regional scale, and if consumers shift to more sustainable diets. If we are indeed what we eat, we should also care deeply about how the choices we make impact the planet that feeds us.

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