A recent study puts the blame on smoking for the loss of Y chromosomes. According to the study men who are smokers tend to have a smaller life span which is associated with the loss of “Y” chromosome.
The chromosome “Y” was discovered in 1890 by Hermann Henking. It was until 1905, Nettie Stevens at Bryn Mawr College identified that it was this chromosome which determined the sex of the organism, particularly humans. “Y” chromosome is the pairing chromosome of “X” chromosome both of which are the final pair of the 23 pairs of chromosomes human genome posses.
Initially as the zygote develops into an embryo the progression will lead to a default gender of the human embryo to be a female. It is until the chromosome “Y” bearer of SRY gene triggers the development of testes the embryo will then be a male. This chromosome is inherited by the father as the mother carries two “X” chromosomes.
There is disintegration of “Y” chromosome as men grow older. Initially this was taken as a normal response of cell to the process of aging.
However, recent studies point out that the loss of “Y” chromosome may not be so normal. The “Y” chromosome tends to be associated with loss of longevity in older smokers. The study seems to suggest cancer to be the leading cause of death in this regard.
The study was conducted over 6000 blood samples from older men. Around 15 percent of the men 70 years of age and above showed at least 10% of “Y” chromosomal loss from the blood cells. The study investigated other causes of loss of the chromosome such as obesity, hypertension, hyperglycemia: Smoking and “Y” chromosome loss showed link.
Although, some of the effects may vary just as it does so in the case of lung cancer – every smoker do not develop lung cancer and every individual with lung cancer does not necessarily have to be a smoker. The study suggests typically older smokers lose more “Y” chromosomes from their blood cells as compared to the non-smokers.
This finding is also supporting the consensus why older smoking men have a higher cancer development risks than women told Lars Forsberg, a Swiss Scientist leading the study.
It was believed that the “Y” chromosome did nothing more that the male sex-determination as two thirds of it were repetition of genes of not many functions but it is now suggested that these not fully understood genes may be associated with regions that suppressed tumor development and the loss of “Y” chromosome from the cell thus will be associated with higher chances of cancer.
In other words the cell’s surveillance system to keep cancerous development in check is lost with the loss of chromosome “Y” possibly because of loss of important tumor suppressor genes lost with it.
Another possible association that the study throws light upon is that smoking may be causing loss of other chromosomal damage which can be picked up by the loss of “Y” chromosomes. Smoking may be causing chromosomal damage other than the loss of “Y” chromosome.
This is just the beginning of the research on the “Y” chromosome. Shortening of age span and increase risk of carcinomas seem to be linked with smoking. These studies are helping scientists take their steps in the right direction when it comes to understanding the sex-determining chromosome “Y”.