- A team of scientists have traced the evolutionary path of Yersinia pestis, a deadly bacterium that transmits through the bite of infected fleas.
- When Y. pestis strains from around the world were analysed, it was found that the bacteria first emerged in China about 6,400 years ago.
- It emerged due to variations in another bacteria Y. pseudotuberculosis that colonized the gut of rodents and other mammals. Y. pestis then gradually entered into the blood stream of the animal later finding its way into the fleas that fed on these animals.
- The bacteria enter into the midgut of the fleas and replicate rapidly forming a biofilm that blocks the entry to its mid-gut. Post this, each time the flea takes a blood meal in an uninfected animal, it regurgitates and the bacteria enter into the animal.
- Its evolution is attributed to it picking up the ymt gene from another bacterium, and losing 3 genes.
- The study reinstates how gene loss can be critical to the evolutionary process as gene acquisition.
- Read at: http://www.thehindu.com/todays-paper/tp-features/tp-sci-tech-and-agri/evolution-of-a-killer/article6035205.ece
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