We have learned that the same information is saved in the DNA in the same place. So when DNA splits and then connects again (during reproduction); how does it maintain the integrity of the information? In other words, do they split and come back like a zipper, or does something else happen?

DNA reproduction

  • $\begingroup$ It is not clear what you want to ask $\endgroup$
    Commented Apr 25, 2015 at 14:21
  • $\begingroup$ I think he's asking if whether the DNA post-division needs to be the the exact same spacial configuration as in the mother cell. $\endgroup$
    – CKM
    Commented Apr 25, 2015 at 14:42
  • $\begingroup$ DNA and nucleotides don't separate and come and go on their own. Spefific enzymes mediate these processes. So it's not like the two strands of DNA suddenly separate and nucleotides wandering around just come and hybdridize. I suggest you to do some research on DNA replication. If you're interested in that, please edit your question, and we'll be happy to answer. $\endgroup$ Commented Apr 25, 2015 at 16:36
  • $\begingroup$ I still don't understand this question and am unsure why it was reopened. It's not even clear if the edits reflect the original intent. This doesn't seem answerable unless the OP clarifies what they are asking. $\endgroup$
    – canadianer
    Commented Apr 27, 2015 at 2:36

2 Answers 2


In the case of replication the parent strands do not pair up back into the original helix. Instead, as your picture and the one below show, the complementary bases are paired up on one of the parent strands, resulting in two copies, each with one parent strand and one new one.

Source: Kathy's webpage on DNA


When I was reading the question, I had a flash of insight into what I presume the question the OP is asking: how do we maintain "integrity" of DNA when we get a set of DNA from mother, and the other set from father (ignoring mitochondrial DNA and other neat things). I would assume this is the question due to the key word reproduction, but anyway,I am here to provide an answer.

As an answer:

I believe the OP has a misconception. DNA of the parents do not pair up in the progeny. Rather, we have 23 pairs of chromosomes, or 46 total chromosomes. What does this mean? The set from the mother and the father do not come together, like a zipper, and have certain bases that just happen to be different (due to single nucleotide polymorphisms and whatnot). Instead, there are two sets of DNA, each with a double helix.

I think this may be what AliceD is also conveying, but I wished to add some more points such as bringing to numbers to help clarify. If I misunderstood, please clarify!


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