Definition

Inheritance refers to the transmission of genetic information across generations. There are two types of inheritance patterns in humans: Mendelian nuclear inheritance and non-Mendelian mitochondrial inheritance. The 23 pairs of human chromosomes located in the nucleus of the cells make up the human nuclear genome. This genome contains an estimated 30 to 40 thousand genes that we inherit in combination from our parents. These genes are called Mendelian-inherited nuclear genes, after Gregor Mendel, the Austrian monk who first established the laws of inheritance in the late 1800s. There is also DNA, called mitochondrial DNA, or the mitochondrial human genome, in the cytoplasm that we inherit almost exclusively from our mothers. These mitochondrial genes are called non-Mendelian-inherited mitochondrial genes.