The unceasing noise of the city bustle and the constant sounds emitted by the transport cause the shortening of telomeric DNA segments in birds.
Scientists representing the Max Planck Society for the Ornithology Institute, together with staff from the University of North Dakota, found that constant city noise leads to shortening of telomeres in young avian species of finder weavers.
Telomeres are finishing chromosomal patches that, in fact, do not possess any unique genetic information, but provide protection for coding genes from damaging factors. At each episode of cell division and DNA doubling, the copying micromechanism does not read the DNA to the end. And in order that the substantial segments of the genome do not “spoil”, they hide behind uninformative sections that can be shortened by a certain point. That is, telomeres cannot be infinite, and their shortening predetermines one of their aging patterns - when telomeres disappear, DNA is damaged, malfunctions from the body appear.
The length of telomeres largely depends on the presence of stresses, which greatly contribute to their shortening. One of the stress factors is noise: that is, we can safely say that in conditions of constant polyphony, birds age more quickly.
Scientists conducted an experiment, taking about 250 young birds and dividing them into four groups. The first chicks lived in silence. The latter also lived in silence, but their parents suffered from sound stress even before the laying of eggs. The third bird group felt noise for eighteen days after leaving the egg. The fourth group lived in a noisy environment from 18 to 120 days of their life.
It was found that the long stay of bird parents in noisy conditions did not affect the length of telomeres in their children. However, in those birds that were exposed to city noise after leaving the egg, a pronounced telomere shortening was observed.
Researchers suggest: in the period when the young individuals begin to emit their own sounds, they become hypersensitive to other environmental noise. Most likely, this is the basis of the violation.
Constant sound load can also harm a person: for example, if he lives near a noisy highway, or works in a noisy industry. However, research on the influence of polyphony on the length of human telomeres has not yet been conducted. Scientists only suggest that sound stress can have a special effect on adolescents and young people who have many vulnerabilities due to the imperfect state of the nervous system.
Details of the study are described in the publication Frontiers in Zoology (https://frontiersinzoology.biomedcentral.com/articles/10.1186/s12983-018-0275-8).