(ORDO NEWS) — It took people centuries to understand that there is evolution – a continuous process of development and change. Now, for decades, scientists have been trying to understand the principles of evolution.
For a long time it was believed that the evolution of living organisms, to put it simply, is a chain of random mutations and their accumulation. Some mutations do not affect anything – for example, the presence or absence of a hump on the nose.
Others become dangerous and their carriers die out without passing the mutation on. Beneficial mutations contribute to survival and are therefore passed on to the next generation. Collectively, this is called natural selection. But a new study calls the “random mutation” theory into question.
“Randomness is not accidental”
For more than a century it has been generally accepted that mutations are random. But the results of a study by an international team of scientists say that this is not the case. Mutations do not occur by chance, but as a response to a certain external stimulus.
The scientific team investigated the HbS mutation that contributes to human protection against malaria. It turned out that most carriers of HbS live in Africa, and in Europe there are much fewer carriers – malaria is practically not found there.
Scientists believe that the mutation does not occur spontaneously and randomly, but in populations where there is a corresponding external irritant – malaria, which helps residents survive in specific conditions.
We assume that evolution is influenced by two sources of information: external information, which is natural selection, and internal information that accumulates in the genome over generations and affects the occurrence of mutations, says Adi Livnat, head of the study.
This point of view is close to the so-called “Lamarckism” – one of the theories of evolution, which states that the organism is able to “direct” its own evolution in the right direction. Simply put, those mutations arise that are relevant and will contribute to survival in specific conditions.
But perhaps, in part, “Lamarckism is alive.” An international scientific team used a new method to understand whether there were random HbS mutations. Only those carriers who did not have parents with HbS were taken into account.
If the mutation were random, it would have to be evenly distributed. But it turned out that it most often occurs in Africa, in populations that are often “under attack” by malaria. Thus, this mutation is not random, but occurs as a response to an external stimulus.
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