Although the family name of Belcher is a prominent one in English and American history, it is actually Old French in origin. The ancestor of the Belcher family came to England from France, as part of William the Conqueror's army that came to England in the Norman Conquest of 1066 A.D.
(Microbiology) any of several viruses whose genetic specification is encoded in RNA rather than DNA and that are able to reverse the normal flow of genetic information from DNA to RNA by transcribing RNA into DNA: many retroviruses are known to cause cancer in animals.
A retrovirus is a type of virus that is used in gene therapy. This is a virus that inserts its genetic code directly into the chromosomes of the host cell (PBS). Other viruses are used for different kinds of genetic problems.his type of gene therapy does not prevent the disease from occurring in the next generation because it does not affect the sperm and egg cells. Somatic cell gene therapy only effects the other body cells.