The Mayo Clinic announced on January 8 that its genomics researchers demonstrated for the first time that human and non-human cells could naturally mix their genetic material in a living body. According to a press release from the Mayo Clinic announcing the discovery,
In the research reported today, Mayo Clinic investigators implanted human blood stem cells into fetal pigs. The pigs look and behave like normal pigs. But cellular analysis shows they have some human blood cells, as well as some cells that are hybrid — part human, part pig — in their blood, and in some of their organs. Molecular examination shows the hybrid cells have one nucleus with genetic materials from both the human and the pig. Importantly, the hybrid cells were found to have the porcine endogenous retrovirus, a distant cousin of HIV, and to be able to transmit that virus to uninfected human cells.
Jeffrey Platt, director of the Mayo Clinic Transplantation Biology Program, said the surprising results may help explain how some viruses can jump so quickly between humans and non-humans. In a press release statement, Platt said,
What we found was completely unexpected. This observation helps explain how a retrovirus can jump from one species to another — and that may speed discovery about the origin of diseases such as AIDS and SARS. The discovery may also help explain how cells in the circulation may become part of the solid tissue.
The Mayo Clinic findings will be published in March in the online Express edition of the Federation of American Societies for Experimental Biology Journal.
Mayo researchers observe genetic fusion of human, animal cells — may help explain origins of AIDS. Press Release, Mayo Clinic, January 8, 2004.