It's also turning out that one of the widely-accepted assumptions - the assumption that vast amounts of DNA were little more than vestigial junk (an assumption that intelligent design people have been predicting for fifteen years would turn out to be false) - is turning out to be false. Researchers are finding that as much as 80% of our genetic material has a function in the cell and that number appears to be a lower limit.
All of which is to say that however the cellular machinery came about it's becoming increasingly unlikely with every passing year that it came about by purely purposeless, mechanistic processes.
Here's an excerpt from the New Scientist article:
After the genome was sequenced, another major project was launched to try to understand which bits of the genome do what. The results, released this week, reveal that our genome is far more complex and mysterious than biologists imagined just a decade ago.You can read the entire article at the link for free for the next four days.
Back in the 1960s, a beautifully simple picture emerged. Our DNA consisted of recipes for proteins. The double helix could be unzipped to allow RNA copies of these recipes to be made and sent to the protein-making factories in cells. But by the 1970s, it had become clear that only a tiny proportion of our DNA codes for proteins - just 1.2 per cent, we now know. What about all the rest? Some assumed it must do something, others suggested it was mostly junk. "At least 90 of our genomic DNA is 'junk' or 'garbage' of various sorts," the geneticist Susumu Ohno wrote in 1972.
Ohno knew, though, that some of the DNA that didn't code for proteins still played a vital role. For instance, the process of making RNA copies of genes - transcription - involves clusters of proteins binding to specific sequences near the genes. These proteins - called transcription factors - control the activity of genes by either boosting or blocking transcription, so the sequences to which they bind are known as regulatory DNA or switches.
So how much DNA acts a switch, or has some other function? To provide an overall picture of which parts of the genome do what, the Encyclopedia of DNA Elements (ENCODE) project was set up in 2003. It involves many teams around the world using a variety of techniques. The results of a pilot study looking at just 1 per cent of the genome were released in 2007. This week, the results of its study of the entire genome were released, with the publication of more than 30 papers in Nature and other journals.
Among other things, ENCODE looked for switches that control gene activity. The researchers did this by taking known transcription factors and seeing which bits of DNA these proteins bound to. So far, they have found 4 million sites, covering 8.5 per cent of the genome - far more than anyone expected.
Even this is likely to be a gross underestimate of the true number, because ENCODE hasn't yet looked at every cell type, or every known transcription factor. "When we extrapolate up, it's more like 18 or 19 per cent," says Ewan Birney of the European Bioinformatics Institute in Cambridge, UK, who is coordinating the data analysis for ENCODE. "We see way more switches than we were expecting, and nearly every part of the genome is close to a switch."
It used to be that anyone who believed that living things were the product of intentional, intelligent engineering were thought to be benighted, hopelessly superstitious, credulous simpletons. It seems that that description is currently shifting toward those who insist that this breathtaking complexity could just happen by mindless accident.
