We tend to look at the whole world through the lens of science, even Valentine’s Day. What could be more romantic than expressing devout commitment to someone as a Valentine’s Day promise? Hanging out, dating, going steady, or whatever you want to call it, most humans tend to enjoy the exclusive company of someone when fluttery emotions get involved. Monogamy is a big part of our romantic relationships. So, let’s dig in and ask a big Valentine’s Day science question: Is monogamy genetic?
Our genes are responsible for a variety of functions in our lives. Genes determine how we grow, how often our body will do bodily things, and is even responsible for passing on photic sneeze reflex (people who sneeze when looking at the sun). Since genetics plays such a big role in the development of our lives, some scientists wanted to see if genes also pass on behaviors like picking a special mate and sticking by their side.
Recently University of Texas scientists looked back on 450 million years of genetic evolution and identified 24 what they call “candidate genes” associated with monogamous behavior in the male brains of some animals. There are many species on Earth that will mate for life, but this study was not about that type of relationship. The definition of monogamy for this study was to have a single mate for at least one mating season and to share the responsibilities of raising their young. Their hypothesis: Could these genes be the genetic indicators of monogamy? If so, then this research would help us better understand that complex social behaviors can possibly be genetic.
Scientists studied five different monogamous species: a pair of poison dart frogs, tilapia fish, warbler birds, deer mice, and meadow voles. So here we’ve got representation from the separate evolutions of amphibians, birds, fish, and mammals. By tracing each of their genetic lines all the way back to 450 million years when all five species shared a common ancestor, scientists observed that 24 genes appear five different times through evolution -- totally independently. Meaning in the evolution of the mammals, frogs, birds, and fish they studied, these animals carry this combination of 24 genes though they are on completely different branches on the tree of life.
For now, we know of at least five monogamous species that all have the 24 candidate genes associated with this behavior. And there are a lot of other things to study before this goes from hypothesis to fact. Regardless, it makes for a good topic of conversation over Valentine's Day dinner with your one special mate … or at least the mate for this season!
From all of us to all of you, Happy Valentine's Day!