Do identical twins have the same gene i.e. the same type of DNA?
This sort of depends on your definition of the “same type of DNA” The basic sequence should be the same. They come form the same sperm and egg. Interestingly… genetics is sort of “old news” now. More recently research has been on epigenetics, which are modifications made to the structure of the DNA later in life. Most of this is simply like turning a switch on or off so that not all genes are active in all parts of the body, but some of it is related to environmental influence, such as diet, smoking, etc. In this way even withing the same person the DNA is not the same, however in common DNA sequencing most of these modifications are not preserved so a normal DNA test would not distinguish between identical twins.
