The worms that have programmed death in favor of their community - La Provincia
Some worms they are genetically predisposed to die before reaching old age, which appears to benefit the colony by reducing food demand, a new study led by University College London (UCL) has discovered.
The modeling study, published in Aging Cell, provides the first evidence of programmed and adaptive death in an animal that has evolved due to benefits to the community.
The main author, the professor David Gems (UCL Institute of Healthy Aging) said: "According to the theory of evolution, altruistic death to leave more food for their peers normally cannot evolve. This is because other individuals who live longer would consume the resources left by the altruistic comrades and compete with them, in what is called a tragedy of the commons.
"But recently it was discovered that wild C. elegans roundworms live in identical worm colonies, which would prevent worms from long life with different genes take control. "
The researchers explain that evolutionary theorists originally believed that aging evolved to reduce population in order to increase food availability for young people, but scientists have shown that this may not be true for most animal species, as longer-lived non-altruists would generally be favored by natural selection.
However, certain organisms have what appear to be self-destruct programs, preventing them from living beyond a certain age. For example, in the small roundworm C. elegansMutations in particular genes can greatly increase your life expectancy, presumably by disabling the life-shortening program.
In the current study, UCL researchers investigated the details of the C. elegans life cycle to understand why programmed death may work for them, designing computer models of a C. elegans colony growing in a limited supply of foods. They tested whether a shorter lifespan would increase the reproductive capacity of the colonies, by generating the equivalent of colony seeds (a form of worm dispersion called dauer).
They found that a shorter lifespan, as well as a shorter reproductive period and reduced adult feeding rate, increased the colony's reproductive success.
The first author, the doctor Evgeniy Galimov (UCL Institute of Healthy Aging) said: "It has been known for years that programmed cell death benefits living organisms, but now we realize that there is also programmed organism death, which can benefit animal colonies" .
The findings have important implications for studies of the biology of aging, many of which are conducted using C. elegans. Other animals have worm-like genes that shorten life expectancy and promote late illnesses, so a better understanding of gene function could contribute to medical research.
But the researchers caution that their latest findings are specific to worms whose life cycles are adequate for such an adaptation mechanism.
Professor Gems said: "Our findings They are consistent with the old theory that aging is beneficial in one way, as they show how increasing the availability of food for your family members by dying early can be a winning strategy, which we call consumer sacrifice. But adaptive death can only evolve under certain special conditions where populations of closely related individuals do not mix with non-relatives. So this is not expected to apply to humans, but it seems to happen a lot in colonial microorganisms. "
Dr Galimov continued: "It seems possible that adaptive death may occur in some types of salmon, which spawn and die in large numbers in the upper reaches of rivers. Dead and rotten salmon have been shown to nourish fry. We call to this a adaptive death form by killing biomass. "
The work illustrates how reduce developmental fitness of individuals can increase the fitness of communities in organisms living in colonies.
The authors say the next stage in their work is to study the actual C. elegans colonies to assess the behaviors predicted by the model, and then use that knowledge to build more realistic models to understand adaptive death.