Is it possible for self-replicating DNA to form with more than two strands in its helix? If not, might it be something to try when we get around to crafting synthetic cells?
2007-09-02 17:57:49 · 5 answers · asked by uncleclover 5 in Science & Mathematics ➔ Biology
Excuse me, that should read, "If _SO_, is it <...>?"
2007-09-02 17:58:31 · update #1
Wow! These all have been informative answers, every one of them - this is quite fascinating! And like any good answerers, your answers raise still more questions! Thanks! :-)
2007-09-03 03:36:34 · update #2
It does occur in nature, but it implies that the replication machinery has been adapted to such DNA features. In a normal cell, physiologically containing double-stranded DNA, the appearance of 3- or 4-strand DNA will undoubtly cause a problem and activate a replication checkpoint. A good example for that is when, following post-replicative DNA repair, the replication fork assumes what is called a "chicken foot" structure (see link) which leads to replication arrest and fork stalling.
2007-09-02 19:46:31 · answer #1 · answered by Jesus is my Savior 7 · 3⤊ 0⤋
The way we understand DNA it would not be possible. Each base has a specific structure which allows only two or three bonds (depending on if the base is a purine or pyramidine) and when the helix is not being held open for replication, all bonds are used. The backbone is also full bonded with the exception of the 3' end of each side. There is nowhere for another strand to bond to.
2007-09-02 18:12:23 · answer #2 · answered by Jessica 4 · 2⤊ 0⤋
I am not sure what advantage having a DNA helix with more than two strands would have. If it is the expression of more genes, it seems more logical to me to simply add additional synthetic chromosomes to the fertilizing gametes. Now, if you are thinking of adding an additional dimension to gene expression, I'm not sure if a multi-helix DNA would be the best approach.
I know that artificial chromosomes have been successfully constructed and made to work in living cells. That seems like the best approach to me.
2007-09-02 18:16:48 · answer #3 · answered by Bob D1 7 · 3⤊ 0⤋
in DNA, the double helix is the most stable conformation, so it would probably be most sensible to use that even if triple-stranded structures occasionally occur. if you're crafting synthetic cells, you're already being pretty ambitious - there is no reason to restrict yourself to DNA as the hereditary molecule.
2007-09-02 19:26:37 · answer #4 · answered by vorenhutz 7 · 1⤊ 0⤋
Yes--it occurs in nature. I've put in a couple of links below.
2007-09-02 18:36:46 · answer #5 · answered by Mark S, JPAA 7 · 1⤊ 0⤋