The genomes of two distinct strains of the virus that causes the common lip cold sore, herpes simplex virus type 1 (HSV-1), have been identified within the same person -- an achievement that could be useful to forensic scientists for tracing a person's history.
The international study is by scientists from the Universities of Lancaster, Penn State, Pittsburgh, Georgia State, Emory and Princeton.
Most people harbour HSV-1, probably acquired from their mothers shortly after birth and carried for the rest of their lives.
This latest research revealed that the volunteer, who is an American of European ancestry, was carrying two strains of HSV1.
One strain of HSV-1 was European and the other Asian, thought to have been acquired during the volunteer's military service in the Korean War in the 1950s.
Dr Derek Gatherer of Lancaster University said this finding had implications for forensic science.
"It's possible that more people have their life history documented at the molecular level in the HSV1 strains they carry. "
Earlier research by the same team has demonstrated that the geographical origin of HSV1 can be predicted too. Since there are Asian, African and European varieties, a personal strain of HSV1 often indicates ethnic background.
Two individuals who have identical strains of HSV1 are therefore more likely to be related than those who have rather different strains.
"Forensic virology could be on the way in the same way in which we use genetic fingerprinting of our human DNA to locate perpetrators at the scene of a crime and help trace the relatives of unidentified bodies.
"Using similar genetic fingerprinting of HSV1 could help flesh out a person's life story, adding an extra layer of genetic information not provided by our genomes alone. "
Some genetic mutations may offer protection against developmental disorders