Michelle Dickenson: nanotechnologist on where kissing originated

When was the first human kiss? This was a question that two scientists – who were married- asked at dinner one night, and their findings were published this week in the journal Science.  The dinner discussion started as the married couple were chatting about a research paper on the ancient DNA of the herpes simplex virus 1. They noted that there had been a shift in the transmission of the virus during the Bronze Age which was potentially lined to new cultural practices such as the advent of sexual-romantic kissing.  “My upper lip becomes moist, while my lower lip trembles! I shall embrace him, I shall kiss him.” This quote was etched in a clay tablet found in what is now India dating back some 4000 years ago and is one of the first literary depictions of humans kissing romantically. A calcite sculpture in the British Museum called the “Ain Sakhri Lovers,” which depicts two humans kissing was found in caves near Bethlehem and is estimated to be about 11,000 years old.  The paper discusses how in research, two types of kissing are generally differentiated:  1 - The friendly-parental kiss  2 – The romantic-sexual kiss.  Whereas friendly-parental kissing appears to be ubiquitous among humans across time and geography, romantic-sexual kissing is not culturally universal. A 2015 study of 168 cultures around the globe found that romantic kissing was popular in only half those groups.  Unromantically kissing enables disease-causing microorganisms to spread from one mouth to another. One study suggests that up to 1 billion bacteria can be exchanged during deep kissing. Diseases including herpes simplex virus 1 (HSV-1), Epstein-Barr virus, human parvovirus and the common cold can be spread by saliva, so kissing can propagate them throughout a population.  It looks like kissing helped to accelerate the spread of herpes throughout Bronze Age Europe as people migrated from Eastern to Western and Central Europe. As population density increased, so did the frequency of kissing and herpes transmission as new immigrants introduced kissing to the locals. Today herpes now inhabits an estimated two-thirds of the worlds population aged under 50, so the virus seems like the biggest winner in this kissing story.  LISTEN ABOVESee omnystudio.com/listener for privacy information.