In what may be an enormously important piece of scientific work, chemist John D. Sutherland of the University of Manchester has discovered a reaction path by which RNA nucleotides can have been assembled from molecules likely to have been present in the Earth’s early environment.
From a story in today’s Times we read:
For more than 20 years researchers have been working on this problem. The building blocks of RNA, known as nucleotides, each consist of a chemical base, a sugar molecule called ribose and a phosphate group. Chemists quickly found plausible natural ways for each of these constituents to form from natural chemicals. But there was no natural way for them all to join together.
The spontaneous appearance of such nucleotides on the primitive earth “would have been a near miracle,’ two leading researchers, Gerald Joyce and Leslie Orgel, wrote in 1999. Others were so despairing that they believed some other molecule must have preceded RNA and started looking for a pre-RNA world.
This explanatory difficulty been a favorite talking point of proponents of the creationist stalking-horse known as “Intelligent Design”; if this new model is correct it will be one less gap for God to lurk in. Peer response seems favorable:
The reactions he has described look convincing to most other chemists. “The chemistry is very robust ”” all the yields are good and the chemistry is simple,’ said Dr. Joyce, an expert on the chemical origin of life at the Scripps Research Institute in La Jolla, Calif.
Not everyone is convinced just yet, however:
Dr. Sutherland’s proposal has not convinced everyone. Dr. Robert Shapiro, a chemist at New York University, said the recipe “definitely does not meet my criteria for a plausible pathway to the RNA world.’ He said that cyano-acetylene, one of Dr. Sutherland’s assumed starting materials, is quickly destroyed by other chemicals and its appearance in pure form on the early earth “could be considered a fantasy.’
Dr. Sutherland is untroubled by this objection, however:
Dr. Sutherland replied that the chemical is consumed fastest in the reaction he proposes, and that since it has been detected on Titan there is no reason it should not have been present on the early earth.
All in all, exciting news. Read the story here.
One Comment
Very interesting stuff.
There is a lot of interesting work on chemical evolution: creating reproducing molecular structures robust to environmental disturbance. One important component seems to be a kind of cell-like wall or boundary separating internal and external environments (political interpretations aside). I think this can be understood in terms of limiting the kinds of information effecting chemical processes can contaminate what must be a somewhat delicate machinery.
If you’ve ever played around with Conway’s game of Life, you probably share my appreciation for the profoundly complicated, beautiful, and yes, life like, patterns emerging from a few simple rules in this cellular-automata, developed by enthusiasts. Most interesting for me are those patterns that repeat themselves. Yet, all of these elaborate structures are toppled into chaos by the flimsiest of winds- they are not robust with respect to disturbance. And so, I think, cannot evolve.