The year 2022 marks the 34th anniversary of the longest running experiment on evolution. It is believed that evolution is caused due to environmental changes, as organisms learn to adapt to new conditions. Humans are also believed to have evolved from primates according to various theories. Organisms respond to change and alterations over a course of several generations. However, findings from this experiment disprove our understanding of how evolution works.
In 1988, Prof. Richard Lenski of Michigan State University conceived this idea. It started with a single petri dish of E.coli bacteria immersed in a solution of glucose, potassium phosphate and citrate. The bacteria metabolized glucose as its only source of energy. In the first few days of inception, bacteria from the dish were taken out and placed in separate containers filled with the same solution. After the experiment reached a large enough scale, only 1% of the contents of each petri container were transferred and the remaining were incinerated. The chance of a genetic mutation to show through was very bleak.
At an interval of every 65 days, a sample was taken out and stored in a cryo-chamber for observation. Many had believed that such an experiment was only a waste of time and would not lead to any alterations in genetics, because the environment (solution) in which the bacteria thrived remained the same. It was only after 15 long years that a change was observed. A strain of E.Coli had somehow managed to utilize citrate as a nutrient source, a major change in its metabolism.
Over the course of two decades, several more findings were made. In some strains, genetic changes had reduced the reproduction speed, while others had deleterious mutations. Such evolution or devolution is seen in humans too, but the fact that they all descended from a common ancestor and thrived in the same environment was astonishing.
Currently the experiment is on its 76,000th generation with many more to come and many discoveries to be made. Evolution without environmental change was a drastic conceptual leap for us humans and has even revealed our false perception of evolution. Such findings beg the question, ‘Whether change causes change?’
Human DNA strand
Comments