Unravelling the mysteries of sexual attraction...
Research conducted by Prof Stephen Michnick and his team at the University of Montreal suggests that a molecular mechanism could explain the mystery of sexual attraction...
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We are all attracted to a certain type of man or woman, but don’t really know why. This is somewhat clearer in the animal kingdom, where a peahen chooses the peacock with the most handsome plumage. But as we all know, human sexual attraction isn’t so clear…
Prof Stephen Michnick and his team recently offered a molecular explanation for this mystery. The research team worked on a much simpler organism than man, namely a yeast used to leaven bread. According to Prof Michnick, "Although yeast is dramatically different from people, at a molecular and cellular level we have a lot in common".
The yeast’s mating decision depends on one single protein called Ste5 being modified. According to the Prof Michnick, this change occurs whenever the cell is exposed to a pheromone produced by another cell (pheromones are chemical signals sent to attract other animals of the same species). As the pheromone signal increases, two enzymes in the cell begin to compete with each other, one adding, the other removing a chemical modification on the protein.
According to researchers, the pheromone causes the two enzymes to modify the protein, adding that the mating decision is "Controlled by a simple chemical switch that converts an incoming pheromone signal into a cellular response".
When the cell is exposed to a sufficient amount of pheromone, "One of the enzymes overwhelms the other’s capacity to modify Ste5, triggering a sudden, switch-like cascade of chemical messages to be delivered to the cell to say it's time to mate".
This decision, which implies the presence of a close-by mate, is very swift. More surprisingly, it appears that the yeast chooses who to mate with, and does so only after a critical threshold of pheromone signal is reached. "Their decision to mate is not just fast, but precise, resulting in the selection of the best available partner, even though there may be many competing potential mates nearby."
This new finding apparently builds a molecular factor into Charles Darwin’s sexual selection theory. More importantly, this research explains how cells respond to pheromones and make critical decisions. Professor Michnick even suggests that, "Perhaps in the near future we can look forward to more discoveries of such switching mechanisms, with the potential of understanding and predicting how humans emerge from the complex process of cells deciding to become different tissues during development and how these decision-making switches break down in diseases."
Likening human sexual attraction to such an uncompromising scientific process seems a bit far-fetched, though, don’t you think? Not much room for mystery and romance there if we are all behaving like yeast!
Source: "The scaffold protein Ste5 directly controls a switch-like mating decision in yeast," Stephen W. Michnick et coll., Nature, April 2010
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Posted 20.02.2012
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