episome (ĕp`ĭsōm), unit of genetic material composed of a series of genes gene, the structural unit of inheritance in living organisms. A gene is, in essence, a segment of DNA that has a particular purpose, i.e., that codes for (contains the chemical information necessary for the creation of) a specific enzyme or other protein.
..... Click the link for more information. that sometimes has an independent existence in a host cell and at other times is integrated into a chromosome chromosome (krō`məsōm')
..... Click the link for more information. of the cell, replicating itself along with the chromosome. Episomes have been studied in bacteria. One group of episomes are actually viruses virus, parasite with a noncellular structure composed mainly of nucleic acid within a protein coat. Viruses usually are too small (100–2,000 Angstrom units) to be seen with the light microscope and thus must be studied by electron microscopes.
..... Click the link for more information. that infect bacteria. As autonomous units they destroy host cells, and as segments integrated into a chromosome they multiply in cell division and are transferred to daughter cells. Episomes called sex factors determine whether chromosome material will be transferred from one bacterium to another. Other episomes carry genes that make bacteria resistant to the inhibitory action of antibiotics. See 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. .

episome

Any of a group of genetic elements consisting of DNA and capable of giving selective advantage to the bacteria in which they occur. Episomes may be attached to the bacterial cell membrane or become part of the chromosome. Cells with episomes act like males during conjugation, a mating process in certain bacteria. During conjugation, cells lacking the episome may receive either the episome or the episome plus the genes to which it is attached. Experiments involving gene transfers from cells in which episomes have been incorporated in the chromosomes have been used to determine the locations of genes on the chromosome.

episome (redirected from episomes)

episome

episome
(redirected from episomes)