As you age, more genes are activated

2012/06/13 Roa Zubia, Guillermo - Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Genetika

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Time leaves several marks in a person's genome. A team of the Institute of Biomedical Research of Bellvitg (Catalonia) has discovered that one of these brands is epigenetics, a genetic characteristic that influences the process of activation of genes.

This feature is the number of methylated cytosines that, as the person's life progresses, are becoming less and less enduring. Therefore, scientists have proposed reducing the amount of these methyl as part of the aging process. Manel Steller, head of the cancer epigenetics research team at the Bellvitg Institute, explained this in an interview with Elhuyar magazine: "At birth we have one epigenome, another in adolescence and another in maturity and old age." Now his team has measured it with the amount of methylated cytosines.

Cytosine is one of the four bases of the DNA molecule. Among other places it is found in gene control points, sometimes associated with a methyl group and sometimes not united. In cases where a methyl is associated, this gene remains inactive. This is important, for example, because a person has two copies of the genome in the cells, one obtained from his mother and another from his father, and because the methylation mechanism of cytosines serves to decide which copy of a gene will be activated and which will not. The Catalan group has found that the number of methylated cytosines varies throughout life.

For this they have compared the genome of a newborn with that of a man of 103 years. The percentage of methylation in the newborn genome is 80%, while in the man genome it is 73%. The researchers also analyzed an intermediate case, of a 26-year-old man, with an average methylation percentage of 78%.

According to researchers, this data helps explain why the body is more vulnerable as age progresses to certain diseases. For several types of cancer, researchers look for epigenetic markers that may form because the proteins that accumulate cytosine work less over time. In any case, these explanations are for the moment hypothesis.