Signatures of evolution of multicellularity in oxygen limiting conditions

The transition of unicellular to multicellular life occurred along with the first presence of oxygen in the environment, leading to the evolution of aerobic metabolism and multicellularity. How this exactly happened is still unknown.

Signatures of evolution of multicellularity in oxygen limiting conditions

“We know multicellularity has evolved at least 25 different times in the history of life on Earth, but we don’t know exactly how it happened,” says Cyrus Mallon, PhD in theoretical and evolutionary community ecology in Groningen. “One thing we do know is that at the time multicellularity first appeared the amount of oxygen in the atmosphere was a fraction of what it is today. So we’re recreating those conditions in the laboratory, evolving bacteria under those conditions, and trying to understand why evolution might favor a multicellular rather than unicellular strategy of survival.”

In the project professor Rampal Etienne and his team hypothesize that minute and fluctuating levels of the early oxygenic atmosphere provided unique conditions for multicellular life to evolve because such conditions selected for a division of labor (DoL) amongst unicellular organisms.

With the use of experimental evolution in chemostats, the research team will evolve all possible pairs of three facultatively anaerobic bacterial species across an oxygen gradient of anoxic, dysoxic, fluctuating anoxia and dysoxia, and oxic conditions.

A chemostat is an apparatus that continuously cultures microbes, such a bacteria, yeast, or even algae. The reactor vessel is constantly fed with fresh nutrient media. At the same time, spent media is also getting removed out of the reactor into a waste vessel. The speed at which the pump feeds fresh media and removes spent media controls the growth rate of the microbial culture.
The chemostat setup in Groningen. It is possible to run 24 chemostats in parallel. The word chemostat is meant to imply that the growing conditions are chemically static, due to the fact the reactor is a closed system. This will allow us to manipulate the level of oxygen in the culture and see how such conditions may influence multicellular evolution.

After 500 generations, the research team hypothesizes a DoL to evolve in the fluctuating treatment, where complete glucose fermentation (anaerobic) is selected for in one species, creating fermentation products (ethanol, acetate, lactate) that will be aerobically metabolized by a second species. This clear separation of anerobic and aerobic metabolism will be confirmed by comparing the transcribed genomes of all treatments. Professor Etienne and his team will also use metabolic modelling to study whether evolving a DoL in dynamic oxygen conditions indeed provides an advantage to each species, and provides a more (evolutionarily) stable solution than a single species performing glycolysis.

This project start in May 2021 and runs until October 2021


Word een fan van het Origins Center en blijf altijd op de hoogte van de laatste nieuwtjes omtrent al onze onderzoeksvelden!
Ik wil me inschrijven

Deze website maakt gebruik van cookies

Cookies kunnen gebruikt worden voor het bijhouden van statistieken, het optimaliseren van de website, integratie van social media en voor marketingdoeleinden.

cookies aanpassen
alle cookies accepteren

Lees meer over cookies in onze privacyverklaring.

deze cookies accepteren