What is ‘junk DNA’?

I’m always hearing people bring up the modern understanding of ‘junk DNA’ as if it somehow lends evidence to the existence of God. It’s not an argument I really get. Whether most of an organism’s DNA is needed or not doesn’t magically disprove evolution. Maybe people just don’t get the concept, I don’t know. I’ll try and give a brief explanation.

About 30 or 40 years ago it was understood that most of the human genome was composed of DNA that served no discernible purpose. That understanding changed with time, morphing from a position of no purpose to one where most DNA was noncoding. This was partially a technical change. Most DNA is noncoding; it doesn’t produce proteins. “Junk” is a misnomer in this context. But we’re discovering more and more that previously deemed purposeless DNA actually does have a function. Often enough it is important in regulation. But still, some 95% of our DNA has no function at all. We may be finding that more of it serves some purpose than we previously thought, but the fact that most of it is useless remains.

I bring this up because of a recent post I saw on an anti-science website (better known as the inspiration for my still-new Punching Bags series – I use it as a hunting ground now). What I find so entertaining about these creationists and their infatuation with junk DNA is that one of the reasons biologists (not creationists, of course) are able to determine that DNA has a function is because of evolution. Sometimes we can directly determine a function through experiment and observation, but much of the time we rely upon inference. DNA which is noncoding yet none-the-less conserved is said to have some sort of function. It must. It makes no sense for a given sequence to exist over millions of years and across distant lineages if it doesn’t serve some function. Of course, this is no problem for those of us on the side of science. Everything really does make sense in the light of evolution. (And you thought that saying was just rhetoric.) But this does pose a problem for creationists. While they’re trying to inanely deny that most of our DNA is not usefully transcribed, they are necessarily relying upon the fact of evolution – the very thing they want to deny.

If it wasn’t for the harm to all of science they cause, I would more easily delight in pointing out how ill-considered creationist ideas really are.

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Oh, woe is me! I’m only white!

This is fucking ridiculous:

  • A recent Public Religion Research Institute poll found 44% of Americans surveyed identify discrimination against whites as being just as big as bigotry aimed at blacks and other minorities. The poll found 61% of those identifying with the Tea Party held that view, as did 56% of Republicans and 57% of white evangelicals.
  • U.S. Census Bureau projections that whites will become a minority by 2050 are fueling fears that whiteness no longer represents the norm. This fear has been compounded by the recent recession, which hit whites hard.

Uh-huh. All that bigotry I face, day in, day out. I just wish brown folk could recognize how bad I’ve really got it. People see me walking down the street and I just know they’re staring! I must stick out like a sore thumb. Especially in Maine. And when I go for a job? Oh, man. Talk about bigotry. I can’t begin to describe how many times I haven’t even been offered a cup of coffee at an interview. And when I go down to the coast in the summer? I swear I got an undersized lobster one time. Bigots.

Augment your reading with Shambling After.