We now live an average of 80-85 years. The reason why some people are even live longer, that is living longer than average, is partly written in their genes.
L ' aging is the process of degenerative cells which, at the microscopic level, together with the entire body, at the macroscopic level, are physiologically meeting. The longevity
defines a lifespan considerably above the average. Today
individuals living in industrialized countries an average of 80-85 years. This figure contrasts with that of less developed countries where men live from 35 to 60 years.
E 'known as the general improvement of living conditions, the advancement of knowledge in medicine and biology with an understanding of the pathological mechanisms underlying many diseases, and the consequent development of preventive strategies before healing, have led to both a increased life expectancy or a decrease in mortality .
It is estimated that world population will reach 8 billion by the 2025.
It is believed that the combined action of multiple environmental factors (lifestyle, physical activity, diet, lack of risk factors such as smoking and obesity) with a specific genetic predisposition may be beneficial to the aging process, both micro that macroscopic, leading in some contexts, even in cases of substantial longevity.
Variable 'HUMAN GENOME
The draft study of the human genome in 2001 has seen the achievement of an epoch-making milestone, with the drafting of a first version of its entire sequence. Technological and financial effort in laboratory has suggested, in about 10 years, to align approximately 3 billion DNA base (deoxyribonucleic acid) of Homo sapiens.
Subsequent characterization studies of this huge sequence itself little information, showed that only about a quarter of it consists of genes. Also, has emerged as the gene sequences actually expressed at the cellular level correspond to only 2-3% of the total genome.
The comparison of genomes of different individuals has even shown that they are basically identical except for a small portion, approximately 0.1% of their total length. This may seem insignificant, however, corresponds to about 3 million bases of DNA.
0.1% In this lies the genetic variability of the human species .
In its 3 million bases of DNA are present in both variants most often, then probably benign, of the genome ( polymorphisms) that any mutations (rare genetic variations), potentially responsible for hereditary diseases.
STUDY OF COMPLEX CHARACTER
polymorphisms thus represent the most common genetic variation, because frequent among individuals and therefore apparently without any detrimental effect on body cells.
A polymorphism is present approximately every 1000 bases of DNA in our genome.
These polymorphisms, over the years, have become a powerful tool for extensive analysis of molecular biology, especially in the field of understanding the genetic basis of complex diseases.
The complex traits, such as aging and longevity in relation to it, rather than the multifactorial diseases such as hypertension ol'infarto, are in fact those contexts where it is believed there may be a complex interaction between genetic factors (individual's own) and environmental (external to the individual).
Over the years, researchers have learned to exploit the presence of DNA polymorphisms within the genomes of every individual, in order to use them as indicators of specific regions of the genome , potentially related to the onset of diseases.
COMPLEXITY 'THE GENETIC BASIS OF LONGEVITY'
The use of genetic polymorphisms to study longevity in humans has been effectively applied by a group of Researchers from Boston University, with the first line in Italian Paola Sebastiani .
The study published in Science was conducted on more than 500,000 different polymorphisms of DNA, comparing the presence among 1055 people aged between 90 and 115 years (mean age 103 years) and 1267 control subjects, mean age 73.
The genetic model obtained by complex biostatistical analysis, focusing on 105 different polymorphisms, located in 77 genes responsible for multiple functions within cells.
Through the presence of these 105 markers, you can make an estimate on the expectation of life, since they are present in 77% of those over age-old suspects compared to controls.
The researchers then assessed the association of these common genetic variants with disease. Emerged then 19 different groups, each consisting of a typical pool of polymorphisms, each of which correlates with the appearance of typical age-related diseases such as dementia, hypertension, cardiovascular disease.
The authors emphasize that the model is not perfect, this confirms environmental factors independent of genetics, can play a role in longevity the human species.
(by Roberto Insolia - Press-Stampa.net)
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