Genetics revealed the unusual connection between sex and heart disease
MOSCOW, 22 Aug — RIA Novosti. Genetics has revealed an unusual Association between coronary heart disease and the success of procreation, which explains why problems with the heart and blood vessels today are the main cause of death, according to a paper published in the journal PLoS One.
“In accordance with Darwin’s theory, the gene variants that help an individual to survive or reproduce, should be distributed according to population, and “bad” versions of them — gradually disappear. From this point of view, the existence of coronary heart disease is completely inexplicable, and we tried to understand why this is so, given its danger to human health,” says Sean Byers (Sean Byars) from the University of Melbourne (Australia).
The development of almost all multicellular living beings manages two factors — natural and sexual selection. In the first case, the evolution of conduct changing environmental conditions, and the second intraspecific competition for the opportunity to procreate. In this fight to win the “bright” individuals, which leads to the appearance of such useless ornaments like peacock tails or scallops roosters, which do not help, but hinder to survive.
The reasons for the existence of sexual selection remain the subject of debate among scientists — the part of biologists believes that it helps the populations to be prepared for sudden changes in conditions, while others believe that such competition protects the species from degeneration and support their competitiveness in the evolutionary “arms race”.
Byars and his colleagues have discovered an unusual connection between these “halves” of evolution that made man genetically and evolutionarily predisposed to developing heart problems and blood vessels in the elderly, by studying variations in the DNA of several hundred residents of Europe, Africa and Asia, associated with coronary heart disease.
This analysis led to some unusual conclusions were that mutations contributing to the development of such health problems in old age, did not disappear from the gene pool, but rather were distributed and accumulated. In other words, the carriers of negative changes in the structure of genes, which lead to the development of coronary disease, left more offspring and more continued kind than other people.
Such a “violation” of the theory of evolution, according to Byars and his colleagues, is associated with sexual selection — some changes that increase the likelihood of heart problems in Mature years of life, apparently, helped their owners to attract the attention of the opposite sex or increased the chances of conceiving a child.
In favor of this said the fact that many of these genes were most active in the genital organs or glands, as well as determined the time of puberty, the start time of menstruation, menopause and the likelihood of survival after birth.
“Evolution seems to have developed an interesting compromise which coronary heart disease begins to manifest itself only on a 40 or 50 year life, when the time for procreation has already left. All this does not mean that women who give birth to a large number of children die more often from heart problems — we were just talking about that coronary heart disease is a byproduct of high human fertility,” explains Byars.
All this, concludes the scientist, suggests that coronary heart disease and other problems of the cardiovascular system prevalent today is not due to the development of civilization and the deterioration of the environment, and for deep evolutionary reasons associated with how our ancestors survived and multiplied in a distant proshlom.