In fact, because ENCODE hasnt looked at every possible type of cell or every possible protein that sticks to DNA, this figure is almost certainly too low. Birneys estimate is that its out by half. This means that the total proportion of the genome that either creates a protein or sticks to one, is around 20 percent.
To get from 20 to 80 percent, we include all the other elements that ENCODE looked for not just the sequences that have proteins latched onto them, but those that affects how DNA is packaged and those that are transcribed at all. Birney says, [That figure] best coveys the difference between a genome made mostly of dead wood and one that is alive with activity.
[Update 5/9/12 23:00: For Birney's own, very measured, take on this,
check out his post.
]
That 80 percent covers many classes of sequence that were thought to be essentially functionless. These include introns the parts of a gene that are cut out at the RNA stage, and dont contribute to a proteins manufacture. The idea that introns are definitely deadweight isnt true, says Birney. The same could be said for our many repetitive sequences: small chunks of DNA that have the ability to copy themselves, and are found in large, recurring chains. These are typically viewed as parasites, which duplicate themselves at the expense of the rest of the genome. Or are they?
To me they have a lot more work to do and haven't sampled the total gnome. So who knows what they will find. Im just think that if there are more parts of the gnome that do something even if its a relatively small role then it expands the importance of some sort of activity through more of the gnome.
As time goes on we may find that more and more of the gnome plays an important role in how our features are made and its relation to disease. It may identify us more specifically from other species and make it harder to see how we could have evolved from apes and how other species evolved to become new species. It may show that this is virtually impossible.
According to
Axel Visel of the Lawrence Berkeley National Laboratory in California and his colleagues, more variation is controlled by distant-acting enhancers. These are short sequences of DNA, in non-coding regions of the genome, that can influence the activity of the facial genes, even if they are a long way along the DNA strand.
"Enhancers are part of the 98 per cent of the human genome that is non-coding DNA long thought of as 'junk DNA'," says Visel. "It's increasingly clear that important functions are embedded in this 'junk'."
So maybe there is more to it that will identify us from apes and other species from each other. It may show that each species is specific and that it is even harder to have mutations affecting change within the gnome to create an new creature. The process maybe more complicated that has been made out and therefore harder to believe that we evolved from a common ancestor.