What would happen if DNA did not make copies of itself during DNA replication?

Answer 1

well, then DNA replication doesn't occur, does it? In this case, the cell does not undergo mitosis. It never gets past the G1 checkpoint, and thus is stuck in a G0 Phase, which is basically a nondividing cell. This happens in many of our cells, such as nerve cells, which do not divide.

However, if u mean that the DNA doesn't replicate, but mitosis goes ahead, then you have two daughter cells with half the original chromosomes. Most likely, both tehse cells would be destroyed. Checkpoints prevent this however; mitosis will not go forth until DNA has been synthesized.

Now that i think about it, mitosis wno't occur properly- mitosis splits the two sister chromatids, but since there are no sister chromatids, then what happens?

Answer 2

If the cells were able to keep dividing even after DNA replication had been suppressed, you would end up with cells having less and less DNA. However, this situation would not be sustainable mainly because the daugther cells would not have the appropriate genomic content and would not, therefore, be viable.

In nature, unless of pathological conditions (such as chromosomes non-disjunction, etc..) cell division without DNA replication does not occur because there are mechanisms of control, called cell cycle checkpoints, which stop the cell from dividing in case of "problems" and make sure of the succession between DNA replication and mitosis (cells need to replicate DNA once and only once per cell cycle, and they can divide only after this has happened).
The most important checkpoint that would be activate in the abscence of appropriate DNA replication is the "intra-S-phase" checkpoint, which will, not only stop cells from dividing through mitosis, but also stop late replication DNA origins from becoming activated if the early origins encounter a problem.
If cells escape this protection mechanism and try to divide anyway, another checkpoint, called spindle checkpoint, will stop the cells in mitosis because the chromosomes would not comply with some of the required conditions, i.e. the sister chromatides could not be binding to different spindle poles.

Answer 3

When a human produce sperm or ovum and through meiosis, the number of DNA would be half of our ones. The next generation would have less and less DNa. Well, this could help in evolution because all we need is one generation to witness the evolution.

However, there may b no living things anymore as they would not have DNA.. Or we we be like aliens.

I hope this helps.:)

Answer 4

Not a heck of a lot.

Answer 5

abnormality !

Answer 6

WE WOULD ALL DIE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!