..... Click the link for more information. ; recombination recombination, process of "shuffling" of genes by which new combinations can be generated. In recombination through sexual reproduction , the offspring's complete set of genes differs from that of either parent, being rather a combination of genes from both parents.
..... Click the link for more information. .
lysogeny
Type of life cycle that takes place in a bacteriophage after it infects certain types of bacteria. The bacteriophage's genome (entire collection of genes) enters the chromosome of the host bacterium and replicates together with it. No offspring viruses are produced; instead, the infecting virus lies dormant within the host's chromosome until the host is exposed to certain stimuli, such as ultraviolet light. At that point, the virus genome is removed from the host chromosome and begins to multiply, forming new viruses. Finally, the bacterial host is destroyed (lysed), releasing virus particles into the environment to infect new bacterial cells.
lysogeny [lī′säj·ə·nē]
Lysogeny
Almost all strains of bacteria are lysogenic; that is, they have the capacity on rare occasions to lyse with the liberation of particles of bacteriophage (see illustration). Such particles can be detected by their ability to form plaques (colonies of bacteriophage) on lawns of sensitive (indicator) bacteria. The genetic determinant of the capacity of lysogenic bacteria to produce bacteriophage is a repressed phage genome (provirus) which exists in the bacterium in one of two states: (1) integrated into the bacterial chromosome (most cases), or (2) occupying some extra-chromosomal location (rare cases).
)
Bacteriophages which have the potential to exist as provirus are called temperate phages. When the provirus is integrated into the bacterial genome, it is called prophage. When the germinal substance (deoxyribonucleic acid or deoxyribonucleoprotein) of certain temperate phages enters a sensitive bacterium, the outcome may be death (lysis) for the bacterium as a result of phage multiplication, or it may result in the integration of the phage nucleic acid into the host genome (as a prophage), with the formation of a stable lysogenic bacterium. The lysogenic strain is designated by the name of the sensitive strain followed, in parentheses, by the strain of lysogenizing phage, for example, Escherichia coli (λ). Such a bacterium differs from its nonlysogenic ancestor in one very special way: It is immune to lysis by phage homologous to its carried prophage. See Bacteriophage
How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content.
| ?Page tools | ||
|---|---|---|
|