Is DNA the same in all cells of the body?
Yes!!! DNA is same in all cells of the body.
All the cells of the body have the same DNA and thus same genes. But then question arises that how there are many different types of cell such humans have liver cells, muscle cells, skin cells, brain cells etc ???
The answer to this lies in the expression of the genes that differs between cells that leads to different tissues and organs.
Expression of genes means that information from the DNA is copied and made into protein. The on and off combination of genes are called as expression that determine the particular function and shape of cell.
There are about 20,000 human genes and all genes are not expressed in all cells as their expression depends on cells types, location and functions in a human body. Therefore, different genes are expressed and others are repressed.
Almost all cells have the same DNA, but there are a few exceptions also such as :
– Mature red blood cells contains no DNA.
– The sperm and the egg cells have half amount of DNA.
– Some of the DNA in B cells has been rearranged to make antibodies.