Dictionary > Phase variation

Phase variation

phase variation
(Science: microbiology) alteration in the expression of surface antigens by bacteria.
For example: salmonella can express either of two forms of flagellin, H1 and H2, that are coded by different genes. Control of which form is expressed is brought about by inversion of the promoter for the H2 gene, which if functional (noninverted) is associated with the expression of H2 and the production of a repressor of the H1 gene.
inversion occurs about every 1000 bacterial divisions and is under the control of another gene, hin, that is within the invertable sequence.


You will also like...

Electromagnetic spectrum of a brain
Sleep and Dreams – Neurology

While learning and intelligence are associated with the functions of a conscious mind, sleep and dreams are activities o..

Early Earth
The Origins of Life

This tutorial digs into the past to investigate the origins of life. The section is split into geological periods in the..

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..

complete-dominance
Dominance

This tutorial presents Gregor Mendel's law of dominance. Learn more about this form of inheritance and how it can be pre..

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..

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..