i really need to know this :) kthanksss
2007-04-24 19:35:03 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Biology
That is not really true of single cell organisms. When they split, they are normally identical.
The following applies to multicellular organism. DNA is exchanged in meiosis between the sister chromosomes in a process called crossing over. That greatly increases the variability of chromosomes or distribution of genes on each chromosome over time. Each gamete (egg or sperm) is then allocated a randomly distributed single set of chromosomes. Because of the usually large number of chromosomes in eukaryotic organisms (non bacteria) it is unlikely that many sperm or eggs will be exact. It is even more unlikely that any two identical sperms will meet two identical eggs.
2007-04-24 19:43:08 · answer #1 · answered by bravozulu 7 · 1⤊ 0⤋
We don't know that it's unique. We know your DNA differs from that of any non-human lifeform, since the number of genes is different. We know that the probability that someone (other than your identical twin) has DNA identical to yours is infinitesimally small. But we don't know that it's impossible.
2007-04-24 19:43:11 · answer #2 · answered by Frank N 7 · 0⤊ 0⤋
random assortment and recombination during cell division. there are 2^23 possible combos. environment has a lot to do with it too, e.g., skin color.
2007-04-24 19:52:17 · answer #3 · answered by La TRI 1 · 0⤊ 0⤋
Recombination, mutation, and independent assortment...
2007-04-24 19:57:58 · answer #4 · answered by Anonymous · 0⤊ 0⤋
Because if we all had the same DNA. we would look the same...grow the same.
2007-04-24 19:40:31 · answer #5 · answered by Anonymous · 0⤊ 1⤋