Extranuclear inheritance

This article or the following section is not adequately provided with supporting documents ( e.g. individual evidence ). Information without sufficient evidence could be removed soon. Please help Wikipedia by researching the information and including good evidence.

This article has been registered in the quality assurance biology for improvement due to formal or content-related deficiencies . This is done in order to bring the quality of the biology articles to an acceptable level. Please help improve this article! Articles that are not significantly improved can be deleted if necessary.

Read the more detailed information in the minimum requirements for biology articles .

As extranuclear inheritance refers to the transmission of genetic information that is not dependent on the chromosomal deoxyribonucleic acid are inherited (DNA). This is why this process is also called extrachromosomal inheritance. The genetic information is not located on the chromosomes in the cell nucleus , but on the mitochondria and plastids . These cell organelles are located outside the cell nucleus and have their own genetic material .

Extranuclear inheritance through mitochondria

In mitochondrial heredity, when an egg is fertilized, mitochondria and the genetic information contained therein are passed on to the zygote . Thus, mitochondrial DNA (mtDNA) is inherited. Mitochondria can only be inherited maternally. Mitochondria are passed on via egg cells, as sperm cells only contain haploid chromosome sets and no cell organelles due to a lack of space. As a result, the inheritance of the affected genes located on the mitochondria is not subject to Mendelian inheritance rules .

Consequences of mutations in the mtDNA

Since mitochondria are inherited exclusively through the maternal line, mutated mtDNA may also be inherited from the mother. Since the paternal genome cannot be inherited in this case, the mutation of the mtDNA is passed on from the mother to all offspring. Mutated mtDNA can lead to hereditary mitochondrial diseases.

Extranuclear inheritance through plastids

This special extranuclear inheritance is the inheritance of plastids in plants. Affected genes, which are located on the organelle, are passed on through the plastids .

Comparison: process of inheritance through mitochondria and plastids

Unlike mitochondrial inheritance in humans, there are different types of inheritance of plastids in plants. The respective inheritance process depends on the type of plant. Among other things, plastids, like mitochondria, can only be passed on maternally. In that case, the flower would pass on the plastids and the pollen would only provide the nucleus. In addition, plastids can also be inherited exclusively through pollen. Mitochondria, on the other hand, cannot be inherited paternally due to the too small size of the sperm. The inheritance of plastids can take place both through the flowers and through the pollen.