The deeper we look, the more complex order we discover.
Biologists studying DNA have discovered another pattern of code within the genetic code. This pattern may regulate the placement of nucleosomes:
Biologists have suspected for years that some positions on the DNA, notably those where it bends most easily, might be more favorable for nucleosomes than others, but no overall pattern was apparent. Drs. Segal and Widom analyzed the sequence at some 200 sites in the yeast genome where nucleosomes are known to bind, and discovered that there is indeed a hidden pattern.
Knowing the pattern, they were able to predict the placement of about 50 percent of the nucleosomes in other organisms.
The pattern is a combination of sequences that makes it easier for the DNA to bend itself and wrap tightly around a nucleosome. But the pattern requires only some of the sequences to be present in each nucleosome binding site, so it is not obvious. The looseness of its requirements is presumably the reason it does not conflict with the genetic code, which also has a little bit of redundancy or wiggle room built into it. (via the New York Times)
Another way of looking at it: If chunks of genetic code are like pages in a recipe book, then the nucleosome code would be like the binding holding the pages in order. It makes me wonder how many other hidden patterns are holding together these tiny books of life.
Out in space, other hidden layers have been revealed this week, as Cassini captures radar images of extra-terrestrial lakes:
(via NASA Planetary Photojournal)
Of course, these lakes, which appear near Titan's poles, are not filled with the crystal blue water that we are familiar with. Rather, these lakes are probably filled with a murky, brownish solution of liquid hydrocarbons. For this reason, I wouldn't expect these lakes to become some space tourist destination any time soon. These pools of ethane and methane probably make places like the Great Salt Lake or Hot Sulfur Springs smell nice in comparison.
Image notes: Chromosomes via Ceska, image of Titan via NASA Planetary Photojournal
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The paper is both interesting and perplexing. I realize that 50% is actually quite better than it sounds on first approximation, but it is written in quite an obscure fashion and the figures are not very reader friendly. Their methodology though I think was the correct one.
Ethane and methane are both odorless in their pure form. . . The nasty smell associated with methane gas is put there intentionally: the gas company puts a sulfur-containing compound (say, ethyl mercaptan) into domestic gas so people can sniff leaks.
I wonder what the actual sulfur content of Titan beachfront property is?
Punko, I've only had a chance to glance at the paper, so I couldn't agree with you on the style, one way or the other.
Blake, I knew that... I suppose I was having one of those brain farts (which are also odorless?) I would be surprised if the brownish organic haze of Titan smelled unpleasant, though.
nice article
Please could you tell me where did you get that wonderfull chromossome image?