Men can live as long as women, but this does not happen because of the loss of blood cells the Y-chromosome. How to use a blood test to predict the risk of cancer and Alzheimer’s, as well as how to restore the lost chromosome?
Globally, women live on average 5% longer than men. Scientists have been trying to find an explanation for this phenomenon, however, has not yet advanced beyond hypotheses and assumptions. For example, the doctor of medical Sciences, President of Society of specialists in evidence-based medicine and a member of the Advisory Committee on health research who / Europe Vasily Vlasov, the life expectancy of the fairer sex can be more for two reasons:
first, the ladies from the disease can protect their hormones, and secondly, women tend to be less aggressive and self-destructive behavior.
But now a team of Swedish scientists from Uppsala University conducted a study and found that the life of men is greatly reduced due to loss of Y chromosome in some cells the blood. The text of this work can be found in The American Journal of Human Genetics.
In a study of Swedes took part 3.2 thousand men at the age from 37 to 96 years.
With the help of a blood test, scientists found that the Y-chromosome, which is responsible for determining the male sex of the body and for normal formation of sperm, is missing in the blood cells and 17% of volunteers.
“It is noteworthy that the loss of Y-chromosome seen in older men”, comment the investigators.
In addition, scientists have determined that men with missing sex chromosome the higher the probability of becoming a victim of Alzheimer’s disease or cancer. According to the authors, due to the fact that the Y-chromosome are losing blood cells called “lymphocytes”, namely, they are involved in ensuring the normal operation of the immune system. While one of the functions of the immune system is the search and destroy cells with pathological changes, such as cancer cells or brain cells, which accumulate beta-amyloid (the protein accumulation forms the plaques characteristic of Alzheimer’s disease). “We can’t say that men with a missing Y-chromosome will develop Alzheimer’s,” say scientists.
— In our study involved a 90-year-old volunteer without this chromosome in blood cells, but he had no hint of disease”.
Nevertheless, the authors believe: a missing chromosome can be considered as a biomarker (a biological characteristic), indicating a possible risk men. That’s why scientists think that in every country men should be regularly to donate blood to understand they are at risk or not.
Earlier, the same team of scientists found that the loss of Y chromosome contributes not only advanced age but also the presence of harmful habits, particularly particularly at risk are heavy smokers. “Maybe that’s why smokers often get cancer,” he suggested Swedish scientists. The corresponding article was published in the journal Science in 2014.
Interestingly, the researchers noticed in men who quit Smoking, the Y-chromosome can recover.
In the future, the Swedes plan to study the connection between loss of the Y chromosome and the risk of dementia, and find out what kind of forms of cancer most often affects men who have lost their sex chromosome.
“To date, most genetic studies of inherited mutations, however, need to pay attention to the mutations that we acquire throughout life, — concluded the study’s lead author Lars Forsberg. — Is acquired by studying the mutations, we understand how to prevent cancer or Alzheimer’s disease, leading to early death.”
Interestingly, earlier, foreign media reported: because the Y-chromosome on Earth soon there will be representatives of the stronger sex. This theory was expressed by an Australian researcher Jennie graves. According to women, after 5 million years on the planet there will be no men due to the fact that the sex chromosome is slowly but surely being destroyed in the course of evolution (it once contained more than 1 thousand genes, but at the moment their number was reduced to hundreds).
In fact, however, the Australian is not right: it is suggested that the Y chromosome is losing genes and mutates at the same rate as in the time of separation of the two sex chromosomes (this happened from 160 million to 210 million years ago).
In fact, over the past 6-7 million years the Y chromosome has not lost a single gene, and for the last 25 million years — only one.
