Slashdot Mirror

← Back to Stories (view on slashdot.org)

Parity Code And DNA

Posted by timothy on from the how-many-noses-sir dept.

jnana writes "There's an interesting article in Nature about error-correcting parity code in DNA. It seems that there are enzymes that check for even-parity nucleotides (according to a 0 and 1 assignment scheme in the article) and recognize odd-parity nucleotides as errors. The authors argue that this parity scheme is the reason that adenine, thymine, cytosine, and guanine became the building blocks of nucleotides instead of other types of purines and pyrimidines that must have coexisted with them."

1 of 43 comments (clear)

  1. No parity, interesting complementarity by Ichoran · · Score: 5, Interesting

    As the previous poster pointed out, there isn't any parity to speak of in DNA. I have no idea why they're trying to make the comparison.

    Hydrogen bonding is a much higher-fidelity error correcting system than parity checking. With parity checking, you can catch any single error (the number of 1's changes), but not any pair. With hydrogen bond donors and acceptors, you have to have an exact match at all positions. Any number of errors ruins the complementarity.

    For what it's worth, the base pairing system is quite elegant: due to size constraints, purines (A,G) and pyrimidines (C,T) must pair with each other. Using the article's notation of 0=H-bond acceptor, 1=donor, the four nucleotides are
    A = 10_
    C = 100
    G = 011
    T = 101
    where _ is simply a hole. The best pairwise complementarity is (evidently) AT and CG.

    It's a chemically implemented RAID-1 system, not a parity check.