Dictionary > Nullisomy

Nullisomy

Definition
noun
(genetics) A type of aneuploidy characterized by the loss of a pair of homologous chromosomes
Supplement
Aneuploidy is a chromosomal variation due to a loss or a gain of one or more chromosomes resulting in the deviation from the normal or the usual number of chromosomes. The different conditions of aneuploidy are nullisomy (2N-2), monosomy (2N-1), trisomy (2N+1), and tetrasomy (2N+2).
Nullisomy is a genome mutation where a pair of homologous chromosomes that would normally be present is missing. Thus, in nullisomy, two chromosomes are missing, and the chromosomal composition is represented by 2N-2. Individuals with nullisomy are referred to as nullisomics.
Nullisomy is caused by a nondisjunction during cell division, particularly meiosis. Nondisjunction occurs when the homologous chromosomes (or sister chromatids) failed to separate. The outcome would be a gamete lacking a pair of homologous chromosome and another gamete gaining that pair. The gamete lacking that pair would give rise to a nullisomic or a nullisome whereas the gamate gaining that pair would give rise to a disomic. A disomic individual is one exhibiting disomy, i.e. an aneuploidy characterized by having one or more chromosomes present twice. Nullisomes, particularly higher animals, would not be able to survive. In plants, nullisomy may produce viable polyploid plants.
See also:

Related form(s):

  • nullisomic (adjective, of, relating to, or characterized by, nullisomy; noun, a cell or an organism in nullisomy and a chromosomal composition designated as 2N-2)

You will also like...

Cells in different stages of meiosis
Meiosis – The Genetics of Reproduction

Meiosis is a form of cell division that creates gametes. It is comprised of two divisions that in the end, the resulting..

Pollution in Freshwater Ecosystems
Pollution in Freshwater Ecosystems

There are many environmental factors that arise due to the usage of water in one way or another and for every action tha..

Crossing Over and Genetic Diversity
Inheritance and Probability

Gregor Mendel, an Austrian monk, is most famous in this field for his study of the phenotype of pea plants, including ..

Sensory systems
Sensory Systems

A sensory system is a part of the nervous system consisting of sensory receptors that receive stimuli from the internal ..

Developmental Biology
Developmental Biology

Developmental biology is a biological science that is primarily concerned with how a living thing grows and attains matu..

Biological Energy
ATP & ADP – Biological Energy

ATP is the energy source that is typically used by an organism in its daily activities. The name is based on its structu..

Related Articles...

No related articles found

See all Related Topics