With the advances in the so-called OMICS (Genomics, Transcriptomics, Proteomics, etc.) we are witnessing countless research studies that aim to find the purported genes of a series of human features, from obesity to aggressiveness, including others as exotic as the predisposition to drink beer instead of wine, and other many bright ideas. Genes are found for all kinds of things, and sometimes for nothing. One of the traits whose genetic basis is under researched using such molecular tools is egoism and its alternatives: faithful cooperation and even altruism. In fact, there have even been claims that the selfish gene has been identified.
Like most of the traits of human beings, egoism can have a genetic basis and an environmental one. The genetic basis of such behavior is now subject to research involving a specific group of organisms, eusocial insects (ants, bees, termites…).
These insects include evolutionary related species and groups, some that exhibit “altruistic” behavior and others that seem to show “selfish” conduct. In the former group, the “workers” will look after their fellow beings to the extent of sacrificing their own lives. Furthermore, they do not reproduce; only the “queen” does. However, there are also evolutionary related groups and species among these organisms that do not exhibit such social behavior.
Ongoing comparative studies of the genomes, transcriptomes and proteomes of both groups is starting to identify the genes involved in such behavior. Specifically, it has been observed that the genes that change (in sequence or regulation) from original unsocial behaviors to eusocial behaviors in these species are those involved in traits such as smell, immunology, hormones (especially pheromones) and those related to brain function. However, there are no special genes for cooperation in the DNA of these organisms, only variants of genes already pre-existing in groups that do not exhibit such conduct.
In the human species it is more difficult to conduct such studies, as there are no clearly cooperative and uncooperative groups or species. Despite this, research is being conducted on the possible role played by a series of specific genes that modulate the synthesis of neuropeptides (hormones that are expressed above all in the brain) in relation to cooperative and selfish behaviors.
Thus, in one of these hormones, the oxytocin, it has been established that there are some variations of a single nucleotide within the gene that controls the synthesis of its receptor in the cells. These nucleotide variations determine changes in the level of oxytocin, which in turn may be related to greater or lesser cooperative behavior. Some people with certain nucleotides in the receptor gene have less oxytocin in the cells and may display more altruistic behaviors, while others, with different nucleotides in that gene, would exhibit a greater amount of oxytocin and, therefore, more selfish behaviors. Other nucleotide variants in neuropeptide receptor genes (such as vasopressin or dopamine), or in the monoamine oxidase enzyme (related to the latter hormone), attempts have been made to associate them with altruistic or selfish behaviors.
The problem in all these studies is that it is very difficult to measure the altruistic and selfish predisposition directly in our species. Therefore, indirect measurements are used, such as a person’s spatial orientation skills (which some researchers say may have a negative correlation with altruism), or skills playing “economic” type computer games, etc.
Therefore, what does appear certain for now is that these tendencies exist in our species naturally, even if we do not know -and perhaps we will never know- what genes or sets of genes are involved. Also, and perhaps most importantly, we have to consider that such complex behaviors as these, in addition to our genetic characteristics, may be due to many sociocultural circumstances, and both factors are inextricably linked.
Manuel Ruiz Rejón
Granada and Autónoma de Madrid Universities