Parity Code And DNA

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."

Comments

Parity schmarity

[nebbian]

This sounds to me of another case of "If you look for something hard enough, then you'll find it". In actual fact there is no parity checking there at all.

Parity checking (in computers) involves adding up the number of 1's in a byte, and putting another bit on the end purely as a form of error control. In even parity there are always an even number of 1's in the (byte + paritybit).
In the article they've figured out that cytosine has 1 donor, and guanine has 2 donors. Then they invent the whole parity thing by letting cytosine equal 1 and guanine equal 0, and when you add all the numbers together you get an even number of 1's. Sounds like circular reasoning to me.
If there was a regular parity bit in the DNA to make sure that an even number of G's or A's occur every 8 or so pairs, then fair enough! But what the article is describing isn't the same parity as you get on your serial port.

It's like saying "Let all starfish with 5 arms equal 1, and all starfish with 6 arms equal 0. Add the numbers up and bingo we've got even parity! Nature is a computer!"

Stinks of looking for more funding to me.