Sunday, April 17, 2016

Future Nobel for Soren Overballe-Petersen ?

Followers of this blog will know that Henry Dawson began pushing the importance of the fact that bacteria could take up loose bits of genetic material (now known to be DNA) from their environment and incorporate in their genome, way back in 1928.

Dr Overballe-Petersen claimed much the same thing in 2013, eighty five years later.

So why should the world even care ---- let alone give the man not just a medal, but the most valued medal around ?

There are at least a hundred different strains of strep pneumonia bacteria, based simply on their differing outer wall of sugar slime alone, and Dawson and others showed that if any one strain was left alone with the dead bodies of any other strain, it would soon have outer walls of the exact same composition as those of the specific dead bacteria.

Even in the inadequate genetic knowledge of the 1920s, that could only mean the living bacteria flawlessly taking up the entire and exact gene off the dead bacteria - genes were known not to be swiss army knives or all purpose entities but rather highly specific things - bungle them a tiny tiny bit and they don't work.

Dawson probably focussed his promoting of the importance of this activity on what it revealed of the unexpected sophistication of the supposedly stupid microbe ---- rather than what their taking up of random genes from the environment could mean for evolution.

After all, he could only see the results of entire genes being taken up and then used as intended but in a different being.

He might have suspected bacteria might take up bits of others' genes and use them in new altered ways, but the technology back then was far too primitive to see those sort of events.

Eventually, seventy years later, it was increasingly accepted that many microbes take up DNA from all sorts of beings and slipped them into all sorts of beings - in both cases, that includes us.

But it was still thought that, more or less as Dawson had observed, that they only took the rare big - hence new - pieces of fragile DNA and put them into their genome --- the far more abundant smaller (ie older) bits they simply ate.

Enter young Danish post-doc Overballe-Petersen and the question he sought to answer:

"Let us check to see if all of the short bits of DNA are simply eaten or are some also taken up into the genome."

After all, Soren reasoned, while short bits of DNA are far too short to hold entire genes they are plenty long enough to hold things like stop and start buttons - and putting those buttons in places where they have never been before sometime gives us entirely new genes, not just an old gene in a new place.

He found (probably much to his own surprise and soon rising excitement) that indeed they did.

Not just short new undamaged pieces either but short damaged new pieces and short ancient pieces and even short, ancient and damaged pieces.

So, an extinct Ice Age animal could die and its DNA lie frozen in the ice for tens of thousands of years, then river melt waters could carry it down to the soil home of present day bacteria, hundreds of miles away, tens of thousands of years later, in another kingdom of the Dominion of Life - and still be put into the bacteria's genome and do something.

And on a rare occasion, even do something quite new and quite useful - driving the entire course of global Evolution.

No wonder the tiny weak microbes survived for four billion years - Overballe revealed that all the world's genome, past and present, near and far, whole or damaged was part of their own personal scrapyard of DNA.

Huge new scientific visas now open up in front of us --- all because young Soren dared ask, and then answer, an unexpected question ...

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