ESThe book ‘El rostro de la consanguinidad’ explores the biological and contextual mechanisms behind a romantic relationship.
Genetics is much more than a branch of biology that studies how hereditary traits are passed down from generation to generation. Genetics does cover this, but it also allows us to do many other things, such as curing diseases or catching murderers. It is also an immensely valuable tool for understanding human behavior.
At BeWay, we work every day to unravel the factors that explain our decisions. To do this, we have a large group of professionals, including Francisco Ceballos, Doctor in Biology, specialized in human genetics and biostatistics.
Together with Román Vilas, also a Doctor of Biology, and Gonzalo Álvarez, professor of genetics at the University of Santiago de Compostela, Francisco has just published El rostro de la consanguinidad (USC), a book that explores the complexity of this phenomenon through an entertaining review of myths and facts from our history.
“The decision about whom we have children with is what shapes the next generation”, warns Francisco Ceballos. Currently focused on the study of human behavior at BeWay, the expert relates what he discusses in his book to one of the most primitive and decisive behaviors for humanity: reproduction.
“The behavior of ‘I marry within my own group to find someone who is similar to me’ is very common” Ceballos illustrates. Far from what we might expect in a globalized world, where cultural exchange is increasingly commonplace, according to the geneticist, human beings tend to pair up and have children with people who are like them.
Goodbye to the myth that opposites attract
His words are corroborated by various studies. The most recent, published in September 2023 by the journal Nature Human Behavior. Its conclusion dispels one of the most recurrent romantic clichés: opposites, it seems, do not attract.
After analyzing 133 traits from 80,000 couples, the study concluded that 89% of them were similar. In a statement, lead author Tanya Horwitz, a researcher in the Department of Psychology and Neuroscience and the Institute of Behavioral Genetics at the University of Colorado Boulder (United States), used a humorous metaphor to explain her findings: “Our findings show that birds of a feather are more likely to flock together.”
“These results suggest that even in situations where we feel we have a choice about our relationships, there may be mechanisms at work behind the scenes that we are not fully aware of,” Horwitz concluded. Ceballos is even more emphatic: “We are not free to choose our partner. It is much more genetic, much more about context and behavior than we think.”
The reader may not yet understand the depth of this conclusion, but El rostro de la consanguinidad is proof that who we have children with, and how we relate sexually, has unimaginable consequences. As an example, consider the WEIRD theory (an acronym for Western, Educated, Industrialized, Rich, and Democratic), developed by Joseph Heinrich, chair of the Department of Human Evolutionary Biology at Harvard University.
According to this expert, among the billions of people in the world, there is a small proportion of weirdos, of strange individuals. And who are they? Well, none other than everyone who lives in the Western world.
These people, in general terms, are individualistic, analytical individuals who take responsibility personally, are against nepotism, and feel guilty when they misbehave.
On the other side, there is the non-weird majority, who identify with family values—understood as tribe or clan—in which nepotism governs their actions. This group thinks holistically, takes responsibility for what the community does, and feels ashamed when they behave badly—or someone in their family does—but does not blame others.
Marriage outside the family
Now, the question is: who is to blame for this weird behavior? Well, it turns out that we’ve run into the Church.
The theory of why Westerners are the weirdest people in the world is supported by what Heinrich calls the Roman Catholic Church’s Marriage and Family Program. According to him, the first weird reconfiguration began with reading, something that the institution encouraged to teach the Bible.
This activity caused a change in brain wiring that led, among other things, to the development of more critical thinking among Westerners. As Ceballos insists throughout the conversation, biology and context are more closely linked than we can imagine.
However, the Church did not only promote reading; it did something else: it prohibited polygamy, divorce, marriage between first cousins, and ended the clan tradition. The Roman Catholic Church’s Marriage and Family Program is the perfect example of what Ceballos points out: the way we relate to each other shapes the future of the next generations.
Right now, you may be thinking, “Hey, among kings, everyone married everyone else.” Indeed. As the book rightly points out, if the Habsburgs were known for anything, it was for the motto Bella gerant alii, tu felix Austria nube (Let others wage war. You, happy Austria, get married).
Their strategy for dominating much of Europe was to arrange marriages between related members: cousins with cousins, uncles and nieces… Papal bull and done deal.
The marriage policy of this dynasty will probably always be remembered for the misfortune of Charles II, nicknamed The Bewitched, who had no descendants. According to research carried out by the same group of experts who wrote the book, Philip the Handsome, one of his ancestors, had a consanguinity rate of 0.025. Charles II’s was 0.25, which means that 25% of his genes were repeated, having received the same copy from his mother and father.
But if inbreeding were the only culprit in this matter, what about his sister Maria Theresa of Austria? She managed to have children, died at the age of 44, and, apparently, it was not due to illness. Rumor has it that she was poisoned.
A complex reality
When two people conceive a baby, they pass on their genes, yes, but these genes then dance and dance until they find their place. In this mix, there can be benefits and drawbacks. As Ceballos points out, “it’s not just the cards, it’s also how they are dealt.” One of the most common problems in this dealing of cards is trisomy 21, which leads to Down syndrome.
Consanguinity, the book tells us, “is a truth that is often more subtle and complex than we imagine.” After reading it, the authors hope that, at the very least, one can understand that “the face of consanguinity is not that of Charles II.”
It is also imperative to explore this issue in greater depth. As ethologists Patrick Bateson and Mark Erickson argue, clinical and anthropological evidence suggests that modern cultural practices are altering natural mechanisms that avoid inbreeding, analogous to those that operate in many other species, which would explain the increase in the frequency of incest detected in industrialized societies.
Once again, behavior alters genetics and viceversa. In a few years, we will see what the outcome is.
Team
