Wetenschap - 14 april 2016

Catching evolution in the laboratory

Rob Ramaker

Understanding evolution and ultimately even predicting it. That is the ambition of the evolution biologist Arjan de Visser, who held his oration on Thursday.

Photo: Guy Ackermans

How did the zebra get its stripes, the giraffe a long neck and how did humans loose hair? When talking about evolution, previously biologists could only share rich tales. That time has passed. With controlled experiments scientists are observing how species change in a laboratory setting. The ultimate goal: understanding evolution and predicting it. ‘But’, says Arjan de Visser, personal professor Evolutionary genetics, ‘that is damn difficult.’

Such insights in evolution are not only interesting for scientists, says De Visser. He also applies his work on concrete problems. For example he tests how insensitivity (resistance) to antibiotics arises in bacteria. But also in illnesses such as cancer evolution plays a role. Selection processes cause tumour cells to sometimes become resistant for medicines. It is only an open question how predictable evolution really is.

[Predicting evolution], that is damn difficult.
Arjan de Visser, personal professor Evolutionary genetics.

To answer that question De Visser studied the evolution in a simple system. For example, how does the resistance to one antibiotic in one gene develop. The reduction of evolution to this essence is an approach which he learned in the laboratory of Richard Lenski. This biologist known for experiment which lasted more than 25 years in which he allowed twelve bacterial strains evolve. In this way the process can be followed on the square millimetre, and – because each generation was frozen – they could also look back in time.

De Visser wants to do something similar on a greater scale, and simultaneously follow a greater number of evolving bacteria. In this manner he wants to get an impression of the predictability of evolution. Soon one of his employees is going to start with a machine which puts bacteria in minuscule droplets. In such a droplet a small ecosystem is formed. De Visser questions how the ‘social relationships’ between bacteria influence further evolution.