Question

Does every cell of human body have the exactly same DNA in nucleus, without exception?

Answer 1

Yes, aside from your sperm and egg cells (gametocytes), which only have one copy of each chromosome, and due to independent assortment and crossing over, each gametocyte is not identical to the next.

However, every other cell in your body has the exact same DNA, but depending on where the cell is located and the intended functions of that cell, different genes are activated and others are repressed. Perhaps, I can also mention here that mitochondria have their own DNA (separate from our 46 chromosomes; located in the mitochondria instead of the nucleus, where the rest of the cell’s DNA is located). Red blood cells do not have mitochondria and therefore do not contain this DNA.