U.S. scientists have identified a genetic variation that affects the biological clock so much that can indicate at what time of the day most likely to come death of a person.
Study author Andrew Lim Medical Center Beth Israel (Boston, USA) found that the internal biological clock affect the time of onset of acute clinical conditions such as stroke or heart attack.
Lim and his colleagues were searching for genetic traits that indicate an increased risk of developing Alzheimer's disease or Parkinson's disease. The study involved about 1.2 thousand people over 65 years. All they ever wore a special bracelet that recorded the change of sleep and wakefulness.
The research took an unexpected turn when scientists decoded the genomes of the participants of the experiment. It turned out that the "larks" — people who are inclined to get up early and go to sleep early, have genetic differences from the "owls" — those who tend to sleep longer in the morning and go to bed later in the evening.
Group Lima found a single nucleotide (nitrogenous base, "brick" of the DNA molecule) by the genome «Period 1", which is different from "larks" and "owls". Approximately 60% of people in this point there is an adenine (A), and 40% — guanine (G).
Since man is the owner of a double set of chromosomes, each of us holds a set of AA, GG and AG.
As it turned out, people with a combination of AA woke up about an hour earlier than the media combinations GG, and those who had in the genome "record» AG — half an hour later than the first.
When the researchers analyzed the cases of death among participants in the experiment (many of whom joined him 15 years ago, at the age of 65 years), they found that the same genetic variation may indicate the hour of death.
People with AA or AG genotype died in shortly before 11 am, like most people, while carriers with an average GG died shortly before 6:00 pm.
Lim notes that more research is needed to determine the mechanisms linking these or other genetic characteristics with the characteristics of the biological clock.