The action of a single gene can have a big effect on how long a person lives. This may seem difficult to believe because so many factors go into determining life span, including a host of lifestyle factors and a long list of diseases. Nonetheless, remarkable effects on life span are seen when particular genes are deleted from a person’s genetic sequence. Furthermore, research, particularly involving microscopic roundworms, continues to provide scientists with tantalizing clues about the molecular pathways involved in aging.
Determination Of The Aging/Anti-Aging Gene
When studying genetic basis of aging, scientists tend to work with the other animals with a short life span; that way, they can observe the entire course of an organism’s existence and obtain relatively rapid experimental results e.g. Caenorhabditis elegans, a microscopic roundworm that typically lives to a ripe old age of two to three weeks. Another advantage of using C. elegans is that these worms have a simple physiology and easily manipulated genes. Scientists have found a number of genes in the organisms which are involved in aging process.
Similarly, now researchers who are working on human beings have found that people like Calment actually owe their longevity in their genes. The physician Thomas Perls and his colleagues at Boston University compared the genetic makeup of 801 Americans who were aged 95 to 119 years, with 926 of younger people. 300,000 points they took it under the microscope. They discovered that there is a kind of genetic pattern that unites the super old humans.
SIRT1: The Human Anti-aging Gene
Diet restriction and physical exercise is the basic requirement for the most diet and exercise programs. However, a severely restricted diet is not a good long-term solution for most people, scientists have been trying to find out ways to create the same results without actually cutting the calories.
Dr. Leonard P. Guarente, a biology professor at M.I.T., hit upon a potential answer when he was studying yeast cells. He found out the cells lived longer when they were given very small amounts of food, and Dr. Guarente started manipulating the cells’ genes to determine what part they played in the extended life span. When yeast cells undergoing caloric restriction were endowed with one certain gene, they lived even longer, and when that gene was eliminated by Dr. Guarente, the caloric restriction was for naught, and the yeast cells died. That gene was silent information regulator No. 2, or SIR2.
SIR2 appeared to stop the aging process by stopping the production of waste material in the cell, which allowed the cell to work better for longer. Dr. Guarente also performed this experiment on a roundworm with the same results.
Humans don’t have SIR2, but we have a gene that appears to do the same thing known as SIRT1. Both SIR2 and SIRT1 seem to work the same way in the body but of course in different organisms. They are charged with repairing the DNA within the body and suppressing certain genes. Suppression of genes is known as Gene silencing. This is important because if the wrong genes become activated, the cell’s function could be destroyed e.g. cells may develop a cancer. It may be that cases of Alzheimer’s and diabetes occur because of this type of genetic malfunction. Both of these diseases involve premature destruction of cells in certain parts of the body.
As we age, it becomes harder for SIR2 and SIRT1 (collectively known as sirtuins) to multi-task, so this gene silencing falls. As a result, we end up with the conditions we associate with older age, like cancers, heart diseases and the aforementioned Alzheimer’s and diabetes. It seems that caloric restriction helps sirtuins work better within the body.
Personal genomics is a branch of genomics which is concerned with the analysis and sequencing of genetic material of a person. It involves different techniques to determine the partial or full genome sequencing. Once the genotypes are known, it can be compared with the published literature to determine the probably /risk of development of certain traits or diseases. Automated sequencers have increased the speed and reduced the cost of sequencing, making it possible to offer genetic testing to consumers. Our knowledge of aging, anti-aging and its genetic basis is very useful in personalized genomics and it is presently being used in predictive medicine.