Fertility factor


Fertility factor

The Fertility factor (also known as F factor or sex factor) is a bacterial DNA sequence that allows a bacterium to produce a sex pilus necessary for conjugation. It contains 20 "tra" (for "transfer") genes and a number of other genetic sequences responsible for incompatibility, replication, and other functions. The F factor is an episome and can exist as an independent plasmid or integrate into the bacterial cell's genome. There are several names for the possible states:

*Hfr bacteria possess F factor integrated into the bacterial genome.

*F+ bacteria possess F factor as a plasmid independent of the bacterial genome. The F plasmid contains only F factor DNA and no DNA from the bacterial genome.

* F' (F-prime) bacteria possess an F plasmid that also includes some DNA taken from the bacterial genome.

*F- bacteria do not contain F factor.

When an F+ cell conjugates with an F cell, the result is two F+ cells, both capable of transmitting the plasmid further by conjugation. Unlike other plasmids, F factor is constitutive for transfer proteins due to the gene Tra J. This means that an F+ bacteria can always act as a donor cell. In the case of Hfr, the result are two Hfr cells. When F-prime plasmids are transferred to a recipient bacterial cell, they carry pieces of the donor's DNA that can become important in recombination. Bioengineers have created F plasmids that can contain inserted foreign DNA; this is called a fosmid.


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • fertility factor — See: F factor …   Glossary of Biotechnology

  • Fertility and intelligence — Demographic studies have indicated that in humans, fertility and intelligence tend to be negatively correlated, that is to say, the more intelligent, as measured by IQ, exhibit a lower total fertility rate than the less intelligent. Other… …   Wikipedia

  • Fertility (soil) — Soil fertility is the characteristic of soil that supports abundant plant life. In particular the term is used to describe agricultural and garden soil.Fertile soil has the following properties: *It is rich in nutrients necessary for basic plant… …   Wikipedia

  • factor — 1. One of the contributing causes in any action. 2. One of the components that by multiplication makes up a number or expression. 3. SYN: gene. 4. A vitamin or other essential element. 5. An event, characteristic, or other definable entity that …   Medical dictionary

  • F factor — fertility factor F plasmid …   Medical dictionary

  • F-factor — may refer to: * F factor (conversion factor), a conversion unit used in diagnostic radiology * Fertility factor, a sequence of bacterial DNA …   Wikipedia

  • F factor — The fertility factor, a plasmid that carries the genes for bacterial conjugation and makes its E. coli host cell the gene donor during conjugation …   Dictionary of microbiology

  • F factor — Abbreviation for fertility factor A bacterial plasmid that confers the ability to function as a genetic donor in conjugation. See: Hfr …   Glossary of Biotechnology

  • Total fertility rate — Not to be confused with birth rate. A world map showing countries by fertility rate, 2005 2010 …   Wikipedia

  • Sub-replacement fertility — is a total fertility rate (TFR) that (if sustained) leads to each new generation being less populous than the previous one in a given area. In developed countries sub replacement fertility is any rate below approximately 2.1 children born per… …   Wikipedia


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.