Delving into the enigma of aging has captivated humanity for centuries, with many desperate to cease or reverse this natural process, as it usually signifies the gradual decline of most bodily functions. Although senescence is an inevitable part of life, biologists possess surprisingly limited knowledge regarding the origins of this evolutionary process. It remains uncertain whether aging is an unavoidable occurrence, given that there exist organisms that seemingly do not experience aging at all. Moreover, the concept of negative aging, or rejuvenation, does exist, as some turtles’ vital functions actually improve with age.
In an effort to substantiate a previously unproven theory of aging, researchers at the Institute of Evolution, led by Academician Eörs Szathmáry, sought to demonstrate the validity of this notion. Their hypothesis suggests that, under specific conditions, evolution can favor the proliferation of genes that control senescence.
Utilizing a computer model they had developed, the researchers aimed to test this theory. This algorithm has the capability to simulate long-term processes within populations of organisms and genes under controlled circumstances. Essentially, these models enable the simulation of evolutionary scenarios, producing results within a few hours, as opposed to over millions of years. It is undeniable that modern evolutionary research heavily relies on computer modeling.
The primary question guiding their research was straightforward: Does aging serve any purpose? Does it possess any evolutionary function, or is it simply an unfortunate and inevitable by-product of life? Eörs Szathmáry asserts, “Aging can indeed have an evolutionary function if there is a selection for senescence. In our research, we sought to uncover this selection. According to classical explanations, aging arises within populations even without selection. This is due to the fact that individuals would inevitably succumb to death, whether due to illness or accidents, thus weakening the force of natural selection within the population. This creates an opportunity for genes that have a detrimental effect on chronologically old individuals (thereby causing senescence) to accumulate. This would mean that aging is merely a coincidental result of evolution and serves no adaptive function.”
In the last century, various evolutionary theories were put forth to explain the inevitable nature of aging, which supposedly serves no positive function. Many scientists accepted this as fact, until the discovery of non-aging organisms prompted a reevaluation of the inevitability of senescence. Perhaps aging could even have some benefits. Szathmáry affirms, “It has become widely accepted in the evolutionary biology community that the traditional non-adaptive theories of aging cannot fully explain all the aging patterns observed in nature, thus turning the explanation of aging into an open question once again. Alternative adaptive theories offer potential explanations by suggesting positive repercussions of senescence. For instance, in a changing environment, aging and death may prove more advantageous for individuals, as this could potentially decrease competition and favor the survival and reproduction of more adaptable progeny with better genetic compositions.”
However, this scenario holds true only if individuals are predominantly surrounded by their relatives. Otherwise, during sexual reproduction, non-aging individuals may acquire the better genes from aging populations, effectively nullifying significant senescence.
After conducting their model, the Hungarian biologists discovered that aging can indeed accelerate evolution. In a changing world, this proves advantageous as rapid adaptation can yield the most suitable traits more swiftly, thereby supporting the survival and propagation of descendant genes. This implies that senescence can truly become a beneficial characteristic and be favored by natural selection.