Dictionary > Extranuclear inheritance

Extranuclear inheritance

Definition
noun
A form of non-Mendelian inheritance in which a trait was transmitted from the parent to offspring through nonchromosomal, cytoplasmic means
Supplement
Non-Mendelian inheritance is a type of biological inheritance wherein the patterns of phenotypes do not accord with those as expected in Mendelian laws on inheritance. It includes extranuclear inheritance, gene conversion, infectious heredity, genomic imprinting, mosaicism, and trinucleotide repeat disorders.
Extracellular inheritance is a non-Mendelian inheritance wherein a trait was transmitted from the parent to the offspring not nuclear in nature but involving other organellar genetic material. There are traits manifested in certain eukaryotes that result from extranuclear inheritance. The mitochondria, for instance, contain genetic material independent of the chromosomes inside the nucleus. During the union of gametes, the mitochondrial DNA from the maternal parent is imparted to its offspring. Hence, when the mitochondrial DNA is expressed the resulting traits would be extranuclear in nature, and determined largely as maternal effect. Inherited diseases relating to mitochondria is called mitochondrial disease.
In humans, fertilization brings the male and female gametes together in union to form the zygote. A functional, mature human male gamete is compact since it loses most of its cytoplasmic contents for mobility. The ovum on the other hand is relatively bigger that it contains many cytoplasmic structures. Hence, most of the organellar genetic material would be derived from the female gamete that when the extranuclear DNA is expressed it is largely a maternal effect.
Other organelle that contains its own genetic material is the chloroplast in plants.
Synonym(s):

  • cytoplasmic inheritance

See also:

  • gene conversion
  • infectious heredity
  • genomic imprinting
  • mosaicism
  • trinucleotide repeat disorder
  • maternal inheritance
  • mitochondrial disease
  • non-Mendelian inheritance


    You will also like...

    Angle Oak Tree
    Seed Plants

    Seed plants are vascular plants. They differ from the other vascular plants in producing seeds that germinate into a new..

    Fossil trilobite imprint in the sediment
    Insects

    There are more species of insects than any other species combined. This surely illustrates that insects have the selecti..

    A sperm cell fertilizing an ovum
    Human Reproduction and Fertilization

    For human species to obviate extinction, reproductive mature adults should be producing viable offspring in order to con..

    Transpiration
    Water in Plants

    The movement of molecules (specifically, water and solutes) is vital to the understanding of plant processes. This tuto..

    mRNA
    Protein Synthesis

    Part of the genetic information is devoted to the synthesis of proteins. mRNA, a type of RNA, is produced as a transcri..

    DNA carries genes coding for proteins
    Genetic Information and Protein Synthesis

    Genes are expressed through the process of protein synthesis. This elaborate tutorial provides an in-depth review of the..