Epigenetics is the part of genetics that studies the factors that, without modifying the information stored in the genes, affect how and when this information is manifested in the real world. The information stored in the genes is useless if it is not translated into an action on the outside world. chemical modifications on the ADNor on the proteins that regulate its functioning, affect whether the information it contains can be expressed in the form of proteins or ARN. How and where these modifications occur and how they affect the functioning of genes is the subject of epigenetics.
Epigenetic modifications constitute an additional point of control of the action of genes, a point aimed at making them work more appropriately to the environment to which organisms must adapt after their birth. Many of these modifications are produced in response to the conditions in which the parents find themselves at the moment of conceiving the children, and are transmitted to the children so that the genes work in them in a way adapted to the environment in which the children are born. parents live.
Undoubtedly, one of the most important ingredients of this environment is the availability or not of adequate food. Several studies have shown that the amount of food available to the parents causes epigenetic modifications that are transmitted to the offspring so that certain genes work to adjust their metabolism to the conditions of food availability found by the parents. It makes sense, because normally the conditions in which children are born are usually very similar to those in which their parents lived when they conceived them.
However, the availability of food is not the only factor that determines how metabolism should be regulated. Another of these elements is temperature. Animals, when they are born, and go out into the outside world that is always colder than the maternal womb, need to generate heat, or else they would perish. Heat generation after birth is a fundamental process for survival in Nature and this process depends on the presence of a special class of adipose tissue, called brown adipose tissue. This type of adipose tissue, instead of storing fat, as the better-known white adipose tissue does, consumes it in an accelerated manner to generate heat.
White and brown fat cells originate from the same type of stem cell. Depending on the physical or chemical signals it receives, the daughter cells it will generate will be white or brown. One of the signals on which this decision of the stem cell logically depends is temperature. A cold temperature stimulates the generation of brown adipose daughter cells, while warm temperatures favor the generation of white adipose daughter cells.
Recently, it has been shown that the amount of brown adipose tissue with which one is born has an important effect on the susceptibility to the development of obesity. Since brown adipose tissue burns fat, those with more of it tend to be more resistant to becoming obese. However, it has not yet been studied whether the temperature to which parents are exposed when they conceive their children affects the amount of brown tissue with which they are born, and whether or not this amount depends on epigenetic modifications in the ADN.
To study this question, a group of researchers at the Institute for Food, Nutrition and Health in Zurich, Switzerland, subjected mice to cold or warm temperatures before conception. What they find is that the offspring of the fathers, but not of the mothers, subjected to low temperatures before the conception of their children, generate offspring with a much more resistant metabolism to the development of obesity in adulthood. Studies also reveal that these changes are due to chemical modifications, that is, epigenetic modifications in certain groups of genes, which were already known to influence the development of brown adipose tissue.
The researchers are also studying whether children born with increased amounts of brown adipose tissue were conceived in cold weather and conclude that this is indeed the case. Thus, the temperature to which the fathers, not the mothers, are subjected before conception exerts an important influence on the metabolism of the offspring. It seems logical to think, although it has not been proven, that the more external location of the testicles, but not of the ovaries, may be a factor that explains the difference between fathers and mothers.
It is too soon to be able to say whether it would be convenient to conceive children in winter, with gonadal cold, and without turning on the heating for a few days if we want them not to become obese. I don’t know if this will have the expected effect or not, but in any case, if you decide to try it, try not to catch a cold next winter. Good luck.
Referencia: Wenfei Sun et al (2018). Cold-induced epigenetic programming of the sperm enhances brown adipose tissue activity in the offspring. Nature Medicine.
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