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...

    river
    Running Water Freshwater Communities

    This tutorial introduces flowing water communities, which bring new and dithering factors into the equation for possible..

    Thermographic image of face and neck
    Regulation of Organic Metabolism, Growth and Energy Balance

    The human body is capable of regulating growth and energy balance through various feedback mechanisms. Get to know the e..

    Protein (illustration)
    Protein Variety

    The sequence of amino acids determines the type of protein. Protein is synthesized according to the sequence of nucleoti..

    primitive arthropods
    Arthropods

    The arthropods were assumed to be the first taxon of species to possess jointed limbs and exoskeleton, exhibit more adva..

    Nephrolepis exaltata
    Vascular Plants: Ferns and Relatives

    Ferns and their relatives are vascular plants, meaning they have xylem and phloem tissues. Because of the presence of va..

    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..