2012-05-20 13:41:48
Vaccination was not invented by Edward Jenner, but… ants
One of the scientific topics that interest me the most is the action of genes on our behavior. Due to the difficulty of separating the effect of what is innate and what is learned, the study of this topic is complicated in the human case. Not so in insects. These animals are not educated by their parents, whom they do not know; They don’t go to school either, they don’t suffer from the normally pernicious influence of their also normally cruel classmates. Your behavior is absolutely determined by your genes.
For this reason, a particular behavior in an insect always indicates a process of evolution, mutation and selection of certain gene variants, leading to the development and maintenance of said behavior, which, undoubtedly, must be important for survival. Recently, a behavior that was believed to be only human has been discovered in some well-known insects, and it is none other than vaccination. Surprisingly, vaccination, as a social behavior conducive to the survival of the species, was not invented by the English doctor Edward Jenner in 1796, but… by ants!, probably millions of years ago. The invention must necessarily be the result of the effect of some genes, obviously not of the ingenuity of the ants. Live to see.
VACCINATION OR COMPASSION?
Probably, we all know that unfortunate leprosy patients were formerly separated from society (they still are today in many countries) and forced to live in isolation to avoid the contagion of a disease of which no one understood the cause, which, fortunately, , we do understand today: a pathogenic bacteria (Mycobacterium leprae). Faced with this very inhumane human behavior, Austrian and German researchers discovered that when the surface of the body of workers of a species of ant (Lasius neglectus) was infected by spores of a fungus (Metarhizium anisopliae) potentially fatal for the entire colony, not only The sick ants were not isolated from the rest to avoid the epidemic, but their conspecifics cleaned the spores with their mandibles, despite the consequent risk of contagion. What is the reason for this compassionate and humane behavior in an insect? Do ants possess more compassion and courage than human beings? Even more than the markets?
In a series of spectacular studies, published in the prestigious journal PLOS Biology this month, researchers discover several surprising facts, in a way that is no less surprising. Using molecular biology techniques, researchers introduce a gene into the fungus that turns the spores fluorescent when illuminated by ultraviolet light. In this way, by illuminating this light, they can follow the traffic of these spores from one ant to another after being placed on the body of some workers, infecting them.
The researchers thus discover that the fluorescent spores placed on 15 workers pass to others, probably due to the cleaning, not always perfect, to which the infected workers are subjected. When researchers dissect infected ants and let the spores develop, the fungi grow on up to 64% of the ants that have not been directly exposed to the fluorescent spores. This constitutes sufficient evidence of spread of the infection, which, however, does not appear to cause an epidemic.
ACTIVATION OF DEFENSES
In fact, researchers are able to determine that up to 80% of the workers in any colony can be infected by the spores of the fungus, although only 2% die from it. The researchers also discovered the reason: by analyzing the active genes in the skin and body of the workers infected by the spores, they found that genes for the ants’ natural defenses against fungi were activated more than normal. However, the genes responsible for fighting bacteria were not activated above normal levels, demonstrating that effective and specific gene activation against the fungus occurs in the ant body.
The activation of these defense genes is, therefore, the result of contact with a low dose of infectious spores, a dose similar to a vaccine, which the ants receive when cleaning others, and which is sufficient to activate the innate immune system of the ants. the ants. This activation allows the vast majority of infected ants to be able to prevent the development of spores into mature fungi, which they carry out by feeding on the ant’s body and killing it. It is, therefore, a socially induced vaccination that achieves the survival of most of the workers in the colony. Interestingly, a primitive type of immunization against smallpox was carried out in a similar way in the 18th century, inoculating healthy people with fluid extracted from lesions of mild cases of smallpox.
However, the really interesting genes, at least for the writer, are not those for the ants’ defenses, many of which are already known, but rather those that induce apparently compassionate behavior towards the ant neighbor. The authors of this study say nothing about what they may be and how they could have arisen during the evolution of this species of ant in its fight with the fungus. Ants of impatience will run down my back until further research reveals them.
WORKS BY JORGE LABORDA.
One Moon, one civilization. Why the Moon tells us that we are alone in the Universe
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