v-Src

v-Src is a gene found in Rous sarcoma virus (RSV) that encodes a tyrosine kinase that causes a type of cancer in chickens.

The src gene is oncogenic as it triggers uncontrolled growth in abnormal host cells. It was the first retroviral oncogene to be discovered. The src gene was taken up by RSV and incorporated into its genome conferring it with the advantage of being able to stimulate uncontrolled mitosis of host cells, providing abundant cells for fresh infection.

The src gene is not essential for RSV proliferation but it greatly increases virulence when present.