Origin of Life

The problem of the origin of life is perhaps the most important unsolved problem of modern science. The development of life can be traced back nearly to the time when the Earth cooled almost 4 billion years ago, but there are limited clues as to how it might have developed from non-living matter. One problem is that every living organism has essentially the same core biochemistry, cellular organization, and genetic operation, which is a potent sign that all life shares a common origin but doesn't provide many clues as to how it started.

The simplest forms of life we know already possess a very sophisticated and intricately interdependent biological machinery. How could such a complicated thing have come into existence? Life as we know it requires metabolism to build and operate itself and genetic material to code for the metabolic machinery. Neither can exist without the other, so we are confronted with the chicken and egg problem at the most fundamental level.

Nobody knows how to solve these problems, but clues are starting to accumulate. Essentially these clues are discoveries that show that something like biological precursors can arise quite naturally under plausible initial conditions for our planet. Nicholas Wade, writing in this New York Times article, describes several new clues.

One is a series of discoveries about the cell-like structures that could have formed naturally from fatty chemicals likely to have been present on the primitive Earth. . .

Last month, John Sutherland, a chemist at the University of Manchester in England, reported in Nature his discovery of a quite unexpected route for synthesizing nucleotides from prebiotic chemicals. . .

Dr. Joyce reported in Science earlier this year that he had developed two RNA molecules that can promote each other’s synthesis from the four kinds of RNA nucleotides. . .

Another striking advance has come from new studies of the handedness of molecules. . .

But you need to read the article to get the interesting details, not to mention some useful background. The bottom line, though, is that strong hints about the path from prebiotic origins to life are starting to appear. It may be unlikely that we will ever understand this in detail - it's very unlikely that any fossil evidence has survived - but the story continues to become more plausible.