Medical genetics The normal 46 chromosomes in our body are contained in the center of the cell which is called the nucleus, mitochondria are structures in the cell located outside of the nucleus in the cytoplasm that also contain genes that are separate from the ones in the nucleusMedical Genetics The normal 46 chromosomes in our body are contained in the center of the cell, which is called the nucleus. Mitochondria are structures in the cell located outside of the nucleus in the cytoplasm, that also contain genes that are separate from the ones in the nucleus