Throughout most of human history the principle that all human beings are morally equal is largely unique to the Jewish and Christian traditions. This blog, "The Moral Christian", explores the clash between those whose lives are ordered according to the transcendent teachings of God as expressed in the Hebrew scriptures and Christian Gospels and those for whom no transcendent moral authority exists

Wednesday, August 10, 2011

DNA Components Found In Ancient Meteorites

I’m not quite sure why this is newsworthy except, perhaps, to rile the waters in which creationists and atheists swim. However, I call your attention to this paragraph from the story:

For decades the scientific community had hypothesized that a chemical process inside comets and meteorites could create elements of DNA, or Deoxyribonucleic acid. The ladder-like molecule contains genetic “blueprints” needed to create life and living organisms. It’s made up of four different molecules, called nucleobases, which lock together rung-by-rung in the now-iconic double-helix shape. (my emphasis)

The claim that DNA is necessary to create life is objectively wrong. Scientists do not know the criteria (chemical, physical, or biological) necessary to create life. The importance of nucleic acids for life lies in its ability to mediate reproduction, not create life. How life came into being? No one knows.

Nor is this a minor point. Both sides of the origin-of-life debate often conflate reproduction with creation and this surely obscures the controversy. At the moment, science and scientists do not understand how life came into being.

Truth in advertising: I am a firm believer in evolution by natural selection (ENS, aka Darwinian evolution). But when discussing the merits of ENS, anti-creationists must first acknowledge this essential truth.


AstraSequi said...

I’m not sure about “objectively wrong” – while I think you’re probably right, we don’t know enough about life to say it’s definitely false. There are certainly quite stringent criteria which any candidate for a genetic material must pass – enough variants to encode information, able to be copied with efficiency, stable enough to transmit information with fidelity, simple enough that the building blocks can be easily made from elements that are common enough in the universe.

While there are indeed other candidates, as far as I know they are all nucleic acids (the group of compounds including DNA). Since what they found in the paper was not DNA itself, but nucleobases (some of the building blocks that are found in nucleic acids in general), the data from the paper is still interesting. I think the distinction is a fine one in any case, since as far as we know all life on Earth requires DNA, and has since the earliest forms of life; even if we started with another molecule, as might be the case, we quickly switched over to DNA. I do, though, still strongly agree with your statement that we need to not confuse creation and reproduction (or I would say, abiogenesis and heredity/evolution).

In fact, part of the importance of the paper is that it supports this hypothesis – if these building blocks are found on meteorites, they might be distributed to many planets in the universe, and life would have the same starting point. It is also a likely piece in the puzzle of how life may have arisen ‒ it shows where some of the most important components may have come from. (Not only that, it also provides evidence towards a plausible mechanism for their synthesis, although the articles seem to ignore that.)

I would say it’s being hyped because it’s probably important to our understanding of life. While it doesn’t imply anything conclusively, it will almost certainly be an important component in any theory of the origin of life – whether it is to say that the components came from ammonium cyanide chemistry on asteroids, or to explain why those components probably didn’t play a role. Given that it’s also difficult to find evidence in this field, and that formation of nucleobases in space has long been speculated but never confirmed...Of course, the scientists being from NASA may have something to do with it, since they have more resources to use for outreach. :)

You can also read the full paper for free here.

Michael said...

Thanks for your thoughtful post. I would only take your post as an excuse to once again, make the point that reproduction and creation are two very different concepts. In our debates on the origins of life, we need to keep these two ideas separate.