ARE THERE GENES OUTSIDE THE CELLS NUCLEUS?
Yes. There’s actually another small set of genes that we all possess, inside our cells but outside the cell nucleus. The cell nucleus is where most of our genes reside on the 23 pairs of chromosomes already discussed. The additional genes, which make up less than 1 percent of a cell’s DNA, are the mitochondrial genes, and they exist on circular chromosomes inside mitochondria, the “energy factories” of cells. (The singular for mitochondria is mitochondrion.) What are genes doing inside the mitochondria? There are about 37 genes, mostly involved in energy production, inside the mitochondria. Scientists believe that mitochondria were once independent organisms resembling today’s bacteria, and that when they became part of human and animal cells, they kept their own genes. These genes, arranged on circular chromosomes, carry the recipes for 13 proteins needed for mitochondrial functions. They also code for 24 specialized RNA molecules that are needed to assist in the production of other m