Revealing the genetic code that may be the reason why men are taller than women

On average, men are about 13 cm (5 inches) taller than women. Sex hormones and growth genes are thought to be the main causes of this height difference.

Although many studies have attempted to identify male-specific genes, we still do not fully understand the genetic mechanisms behind this size difference.

We are still trying to figure out why men are taller than women. (Source: Shutterstock)

What we do know is that hormones like testicular androgens play a huge role in making men taller than women from puberty onwards.

However, according to a new report, it remains unclear how these sex hormones interact with genetic growth factors to influence adult height.

Because all previous attempts to identify male-specific growth genes on the Y chromosome – which is found only in males – have been unsuccessful.

SHOX and CYP26C1 gene expression affects height and bone deformities. (Source: Embopress)

To reassess the issue, the researchers cited two recent studies – one of which they conducted themselves. Both papers focused on a growth-related gene called SHOX, which is found on both the X and Y sex chromosomes, so both men and women possess the gene.

Because of this, SHOX has largely been overlooked as a candidate for the male-specific height gene. However, in their study, the scientists found that SHOX is expressed at significantly higher levels in male tissues than in female tissues.

This means that, although the gene is not exclusive to males, it is more active in males than in females. Therefore, it may be the genetic cause of superior height in males.

These findings were reinforced by a second study, in which scientists analyzed height and genomic data from 928,605 people. Of these, 1,225 had sex chromosome aneuploidy, meaning they had an atypical number of sex chromosomes.

Notably, an extra Y chromosome was associated with an additional 3.1 cm (1.2 inches) in height compared to an extra X chromosome. Since SHOX is the only gene involved in bone growth found on these chromosomes, the difference can only be explained by differences in gene expression.

The study also found that abnormalities in the SHOX gene caused a significant reduction in height – 18.6 cm (7.3 inches) in males, but only 8.9 cm (3.5 inches) in females. Again, this suggests that the SHOX gene has a much greater influence on body height in males than in females.

“This finding is consistent with the hypothesis that reduced SHOX expression in females accounts for the sex difference in height,” write the authors of the second study.

Looking at both studies together, the scientists concluded that the SHOX gene on sex chromosomes plays a role in regulating adult height.

However, they also note that SHOX may not be the only factor, and do not rule out the possibility that there are other undiscovered genes or RNAs on sex chromosomes that may influence height by sex.

Mr. Quang

Source: https://vtcnews.vn/he-lo-ma-gen-co-the-la-nguyen-nhan-khien-dan-ong-cao-hon-phu-nu-ar983629.html