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...

Direct and indirect physiologic effects of growth hormone
Animal Growth Hormones

Hormones are produced in the endocrine glands of animals. The pituitary gland and hypothalamus are the most impor..

Population Growth and Survivorship
Population Growth and Survivorship

This lesson looks at population attributes, regulation, and growth. It also covers population genetics, particularly gen..

Biological Cell schematic diagram
Biological Cell Introduction

It only takes one biological cell to create an organism. A single cell is able to keep itself functional through its 'mi..

Evolution of Life - Ancient Earth
Evolution of Life – Ancient Earth

Autotrophs flourished, absorbing carbon and light. Soon after, primitive life forms that could assimilate oxygen thrived..

Freshwater lake ecosystem
Freshwater Producers and Consumers

Freshwater ecosystem is comprised of four major constituents, namely elements and compounds, plants, consumers, and deco..

Human Neurology
Human Neurology

Human Neurology deals essentially with the nervous system of humans. It also features the various theories put forward b..

Related Articles...

No related articles found

See all Related Topics