What is a genome?
The genome is the set of all the genetic material, i.e. all the DNA, found in a living being. An individual’s genome contains enough information to develop a functional copy of itself and its further development. Despite common belief, the genome is not only the DNA found in the cell nucleus, but also includes the DNA of organelles contained in the cell, such as the mitochondria in the human species. In the case of humans, each cell generally carries the same DNA and thus an exact replica of the individual’s genome.
In humans, the genome in the cells is duplicated, except for the sex chromosomes in males, which are diploid organisms. Each of the two copies comes from one of the parents. Because of this, there are diseases in which an individual can carry the disease gene without manifesting the disease. These are so-called recessive diseases, which require both copies of the defective gene to develop. In contrast, for a dominant disease to be expressed, it is sufficient for one of the two genes to have the altered information.