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.
Endogenous retroviruses are always in the state of a provirus. When a (nonendogenous) retrovirus invades a cell, the RNA of the retrovirus is reverse-transcribed into DNA by reverse transcriptase, then inserted into the host genome by an integrase.roviruses may account for approximately 8% of the human genome in the form of inherited endogenous retroviruses. A provirus not only refers to a retrovirus but is also used to describe other viruses that can integrate into the host chromosomes, another example being adeno-associated virus.