Ah, these emotions, butterflies in the lower abdomen … which absorb all our thoughts, intoxicated with the amount of hormones, like a whole box of delicious chocolates, our minds become overflowing, and the flying toddler shoots more a shot than Legolas – a time when our whole body is enveloped in a symphony played by the orchestra, spreading irrational ideas of love. To quote Her latest science-fiction romantic comedy: “This is a kind of socially acceptable madness.”
But maybe love is not as irrational as we think. Some say this is partly due to how we are brought up, while others think it is written in our DNA. As it turns out, both reasons can be true. Various animal studies may suggest that the increasingly important field in medicine and everyday life, the field of Epigenetics (studying mechanisms that regulate gene expression) also plays a role in the way we are loved and in the way we love. Can this fascinating field help explain why someone loves you so much? Here are four possible reasons that are interesting:
# 4 – Their sexual attraction was obtained from their socially and environmentally competitive parents
If your partner’s parents were conditioned in an environmentally and socially competitive community, it means that they were genetically random. Your partner’s parents have probably given him a “sexy gene”, obtaining potentially favourable odour signals called pheromones to lure you. These chemicals are produced and released into the environment that can be detected by animals of the same species. First of all, pheromone production may affect attractiveness and reproduction.
The struggle of competing environments and attracting pheromones was exemplified by the English writer William Shakespeare in the drama Romeo and Juliet, presenting the story of the tragic love of two young people who became models of romantic lovers from environmentally and socially competitive, two feuding families: Capuleti and Montecchi.
In a study by University of Utah scientists, mice that lived in materially and socially competitive populations for mothers gave birth to sons who showed a clear advantage in attracting females. These sons inherited increased expression of pheromones in the family of major urinary proteins (MUPs). This increased expression is associated with changes in DNA methylation that result in a higher concentration of MUP that attracts more females.
Now, thank your partner’s parents for making him such an epigenetic cake.
# 3 – Have less emotional luggage from mothers
What makes a good life partner? In addition to sexual attraction, we are looking for a partner who is emotionally stable and is able to conceive and raise healthy offspring. The amount and quality of care a child receives not only then affects his quality as a parent – the educators he will become, but can also affect how he will deal with independence, fear and stress at the epigenetic level, which ultimately determines his personality as an adult.
Researchers at McGill University have found that puppies, which were often licked and nurtured by mothers during the first few weeks of life, were less fearful and showed significantly fewer stress responses than those who were not treated in the same way. Apparently, changes in DNA methylation and an increase in histone acetylation lead to a cascade of gene expression, causing an increase in the number of glucocorticosteroid receptors in the brain region called the hippocampus (which is primarily responsible for memory but is also very sensitive to stress, which leads it to increase the activity of the hypothalamus axis pituitary-adrenal gland, causing secretion of, among others, cortisol, damaging the hippocampus; a decrease in volume and impairment of the function of this brain structure have been observed, also by increasing oxidative stress and affecting the dopaminergic and serotonergic systems).
# 2 – The environment of their ancestors affects their attractiveness
Have you ever intuitively rejected a date with a potentially great candidate, even though he had all the qualities you are looking for before? It turns out that maybe his great-grandmother worked in a fungicide (fungicide) factory.
SEE ALSO: Maybe she was born with it, maybe it’s epigenetics: 5 tips for beauty and anti-ageing.
Listen, what’s up? Well, environmental factors can change the epigenome in a way that affects partner selection (which can affect population viability and species evolution). Human exposure to environmental pollution by endocrine disruptors (EDCs) can leave a “footprint” that lasts for generations and can affect how attractive you are to others and how attractive it is to you. This partner preference was seen in female rats in a University of Texas study. Researchers treated pregnant female rats with a fungicide and found that the third generation of exposed young females discriminates against and prefers males with no exposure history.
Interestingly, third-generation men who were similarly vulnerable showed no preferences. Preferential behaviour in exposed females may be due to changes in germline DNA methylation that affect the genes responsible for partner selection due to EDC exposure.
Therefore, gentlemen, do not be offended if you fail to pick up this girl – her wonderful, great-grandmother could simply work also in a fungicide factory.
# 1 – “Genes of Love” have been activated in your brain
Society has long been and still dictates in some areas of the world that “connecting” to a partner without first marrying or having a formal relationship is unacceptable and provoking social ostracism. Perhaps, however, such a desire results from a biological predisposition to actively seek one partner for life. Recent studies by researchers at Florida State University have shown that epigenetic activation of genes in the recumbent nucleus, pleasure and reward region of the brain (e.g. during intercourse), prairie voles (Microtus ochrogaster) can lead to monogamous behaviour and lifelong partnership.
In these animals, mating induces the expression of vasopressin and oxytocin receptor genes in the brain, which causes partner preference and behaviour to form pairs for life. Increased gene expression is caused by increased histone acetylation, which relaxes severely wounded chromatin, allowing gene expression. Unexpectedly, in the absence of mating, the same type of behaviour can be artificially imitated by injecting the drug into the nucleus of the recumbent animal, which would give the same effect.
So the next time people tell you that love is in the heart, not the brain, let them the know-how, from an epigenetic point of view, they are wrong (but let them know with love).
- Nelson A., et al., Reintroducing domesticated wild mice to sociality induces adaptive transgenerational effects on MUP expression. PNAS, November 19848-19853, (2013).
- Wang H, et al., Histone deacetylase inhibitors facilitate partner preference formation in female prairie voles, Nature Neuroscience, 919-24 (2013).
- Weaver I., et al., Epigenetic programming by maternal behavior. Nature Neuroscience, 847-854 (2013).
- Crews D, et al., Transgenerational epigenetic imprints on mate preference. PNAS April 5942-5946 (2007).
Disclaimer: The comments presented herein are the author’s speculative opinion based on related scientific publications on animal research and may not actually apply to humans.