Do you know that women normally live much longer than men? This is a difference that can be applied to a female to male population all across the animal kingdom. But why is it so? What do women enjoy longevity?
Genetically, women comprise two copies of the X chromosome. On the other hand, all males have one copy of X chromosome paired with a Y chromosome.
The X chromosome bears thousands of genes, each of these genes encoding for a separate protein. On the other hand, the Y chromosome has a rather poorer quality of genetic material. It mostly consists of the genes that determine male patterns of traits, for example, the development of testes and other masculine features. This part of the gene is known as “SRY.”
A new research has indicated that women tend to live longer as compared to men. This pattern is depicted by a lot of mammals where females normally outlive their male partners.
No one is not sure as to why this happens. However, a new study conducted by the University of California, San Francisco now offers a reason.
The findings of these studies, featured in the journal named Aging Cell reveal that the XX pair of chromosomes naturally consists of certain agents prolonging life. However, this is only applicable in the presence of female hormones secreted by the ovaries.
It is not Only a Game of Genes
In this new study, the scientists utilized a mouse model in order to understand what gives females a longer life. Certain mice were genetically engineered to fit in one of the following four categories: XX chromosomes with developed ovaries, XX chromosomes with testes, XY chromosomes with well-developed testes, and XY chromosome pair with ovaries.
This was successfully achieved by shifting the SRY gene to another chromosome which played no part in determining sex. This meant that the mice were able to inherit it even if they did not inherit the Y chromosome.
The scientists found that the mice group containing XX chromosomes generally outlived the ones with XY pair. This was irrespective of whether they had a pair of testes or ovaries.
Further investigations revealed that of the two groups containing XX chromosome pair, the one with ovaries was able to live longer as compared to the one with testes. This indicated that the hormonal profile is as important as the genetic makeup in the determination of longevity.
XX Chromosomal Pair is an Advantage
Among the two groups of mice with XX chromosome pair and contrasting pairs of gonads, the scientists noticed that the XX chromosomes holding mice who developed ovaries outlived their counterparts who had developed testes. This was measured from the 21-month mark.
The scientist concluded that in order to expand lifetime, it is important for a person to own a pair of XX chromosomes in addition to a pair of ovaries. As far as the normal living is considered, the type of gonads does not matter as long as the person has an XX pair.
The scientists are yet to understand how the addition of an extra X chromosome can decrease mortality and increase longevity.
However, certain mechanisms previously studied by scientists offer useful insights. For instance, one X chromosome in all females tends to get deactivated randomly. This makes sure that if the active counterpart gets damaged, the inactive one can reactive itself to take charge.
While more investigations are required to get to the bottom of this mystery, the scientists stress that individuals carrying XX pair are winners of this research as well as that of the genetics.
For a detailed view of the study, click here.