Categories: Cellular biology; genetics; reproduction and life cycles
Extranuclear inheritance is a non-Mendelianform of heredity that involves genetic information located in cytoplasmic organelles, such as mitochondria and chloroplasts, rather than on the chromosomes found in the cell nucleus.
Extranuclear genes, also known as cytoplasmic genes, are located in mitochondria and chloro-plasts of a cell rather than in the cell's nucleus on the chromosomes. Both egg and sperm contribute equally to the inheritance of nuclear genes, but extranuclear genes are more likely to be transmitted through the maternal line because the egg is rich in the cytoplasmic organelles where these genes are located, whereas the sperm contributes only its nucleus to the fertilized egg. Therefore, extranuclear genes do not follow genetic pioneer Gregor Mendel's statistical laws of segregation and recombination. Cytoplasmic genes are of interest in understanding evolution, genetic diseases, and the relationship between genetics and embryology.
Was this article helpful?