Dictionary > Allelic exclusion

Allelic exclusion

Allelic exclusion
(Science: cell biology, genetics) The process whereby one or more loci on one of the chromosome sets in a diploid cell is inactivated (or destroyed) so that the locus or loci is (are) not expressed in that cell or a clone founded by it.
For example in mammals one of the x chromosome pairs of females is inactivated early in development (see Lyon hypothesis) so that individual cells express only one allelic form of the product of that locus. Since the choice of chromosome to be inactivated is random, different cells express one or other of the x chromosome products resulting in mosaicism.
The process is also known to occur in immunoglobulin genes so that a clone expresses only one of the two possible allelic forms of immunoglobulin.


You will also like...

Lentic community
Freshwater Communities & Lentic Waters

Lentic or still water communities can vary greatly in appearance -- from a small temporary puddle to a large lake. The s..

Plant Auxins
Plant Auxins – Phototropism & Geotropism

Plants produce hormones to regulate their growth. Auxins, for instance, influence plant growth. Know the role of auxin i..

New Zealand - Biodiversity fauna
New Zealand’s Biodiversity

Find out more about New Zealand's unique biodiversity by exploring a range of different ecosystems and the key role of s..

Cell structure
Cell Structure

A typical eukaryotic cell is comprised of cytoplasm with different organelles, such as nucleus, endoplasmic reticulum, G..

green plant cells
Plant Cells vs. Animal Cells

Plant cells have plastids essential in photosynthesis. They also have an additional layer called cell wall on their cell..

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..