Fitness trade-offs linked to population size in E. coli

Scientists at IISER, Pune, have discovered a link between population sizes of Escherichia coli bacteria with the fitness trade-off adopted by them.

Escherichia coli

Escherichia coli is a bacterial species commonly found in the gut of humans and several animals. It is a rod shaped, gram negative bacteria that are mostly harmless in nature. However, some of their species can cause illnesses of the digestive system.


The bacteria can cause food poisoning in its host. It is transmitted through the oral- faecal route. The consumption of contaminated food and water can lead to diseases of the digestive system with symptoms like vomiting, abdominal cramps, diarrhoea, fever, etc.


Living organisms have a finite energy capacity i.e. an organism cannot maximize all its traits simultaneously. This is called fitness trade-off. This means that when an organism increases its proficiency in one trait (eg: adaptation to a certain environment), its proficiency in the other traits declines.

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