Experiences Leave Behind Epigenetic Traces in Our Genetic Material

phys.org |  An ideological dispute is taking place in biology. And it's about a big topic that's central to everything: heredity. In his epoch-making book On the Origin of Species of 1859, Darwin wrote of the reigning ignorance about how differences between individuals come about. It was only with 'modern evolutionary synthesis' in the 1940s that people became convinced that heredity functions through genetics – in other words, that the characteristics of living creatures are passed on to the next generations through their genetic substance, DNA.

This perspective was helpful in providing a focus for research in the ensuing decades, which brought about extraordinary discoveries. As a result, many aspects of the form and function of living creatures can now be explained. But already in the 1950s, different observations called into question the seemingly exclusive control of the genes. For example, maize kernels can have different colours even if their DNA sequence is identical.

Plants remember aridity

Further investigations brought to light the fact that when individuals with identical genetic material have a different outward appearance, this can be traced back to different degrees of activity on the part of the genes. Whether a particular section of DNA is active or not – i.e., whether it is read – depends to a decisive degree on how densely packed the DNA is.

This packing density is influenced by several so-called epigenetic mechanisms. They form a complex machinery that can affix or detach tiny chemical attachments to the DNA. Here, the rule applies that the tighter packed the DNA, the more difficult it is to read – and this means that a particular gene will be more inactive.

Living creatures can adjust to a volatile environment by steering their epigenetic mechanisms. In this manner, for example, the epigenetic machinery can ensure that plants can deal better with a hot or arid climate if it at some point they already had to live through a similar situation. So in this sense, the epigenetic markings in the genetic material form a kind of 'stress memory' of the plants. This much is today a matter of consensus among biologists.

Doubts on heredity over generations

Several studies, however, suggest that the descendants of stressed plants are also better prepared against the dangers already faced by their ancestors. "However, these studies are a matter of controversial debate," says Ueli Grossniklaus, the director of the Department of Plant and Microbial Biology at the University of Zurich. Like many other epigeneticists who are involved in deciphering these mechanisms, he believes that, "since the evidence is patchy, we can't yet say to what degree acquired characteristics can be transmitted in stable form over several generations." So it still remains to be proven whether epigenetics actually brings organisms long-lasting advantages and thus plays a role in evolution. It's an attractive idea, thinks Grossniklaus, but it's still to be demonstrated.

It's not just in plants that results on the heredity of epigenetic markings are causing a stir – the same is true in mice. In order to investigate the possible long-term effects of severe childhood trauma, for example, the research group led by Isabelle Mansuy, a professor of neuro-epigenetics at the University of Zurich and ETH Zurich, has been taking mouse offspring away from their mothers for three hours each day, just a few days after being born.

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medium | The next five years will see the international market for ‘riot control systems’ boom to a value of more than $5 billion at an annual growth rate of 5%, according to a new report by a global business intelligence firm.

The report forecasts a dramatic rise in civil unrest across the world, including in North America and Europe, driven by an increase in Ferguson-style incidents and “extremist attacks.”

The Middle East, North Africa and Asia-Pacific regions will also experience a persistent rise in conflicts.

This increasing trend in instability promises billions of dollars of profits for global defence firms, concludes the report, published last month by Infiniti Research Ltd., a market intelligence firm whose clients include Fortune 500 companies.

“Protests, riots, and demonstrations are major issues faced by the law enforcement agencies across the world,” said Abhay Singh, a lead defence technology analyst at the firm. “In addition the increase in incidents of civil wars in countries such as Syria, Iraq, Lebanon, and Egypt along with an increase in the global defence budget will generate demand for riot control systems.”

Europe, the Middle East and Africa will be the largest market, collectively experiencing a rate of growth at over 5%, exceeding $2 billion by 2020. Under the subheading, ‘EMEA: increase in extremist attacks to boost growth’, the report, priced at over $2,000, explains:

“Over the past years, Europe witnessed an increase in extremist attacks, which has raised concerns among the law enforcement and defense industries to equip themselves with modern equipment and protect civilians from external threats. In 2015, the Paris attacks and the killing of journalists in France are some of the examples of growing terrorism in Europe.”

The combination of intensifying conflict, terrorism, and civil unrest will lead to rocketing demand for riot control systems over the next 5 years “led by Germany, Russia, France, Poland, Saudi Arabia, Turkey, the UAE, Iran, and South African countries.”