Every man starts life as a woman

Table of contents:

Every man starts life as a woman
Every man starts life as a woman
Anonim

Genes and chromosomes: key concepts of the future, about which it's good to learn more than just from Miami-based detectives - our genetics expert sheds light on everything in the new series

article-type-independent
article-type-independent

We have an interesting piece of news: research in recent years has confirmed that each fertilized ovum starts in the direction of the female sex, which is controlled by the DAX gene on the X-chromosome. How do we get there? How and how is it decided whether the fertilized ovum will continue its life as a "woman or a man"? Let's see!

Most people think of the science of heredity, i.e. genetics, as something difficult to understand and complicated. Usually, when we hear the word genetics, we primarily think of having children, the inheritance of certain characteristics, or even cloning. When a woman and a man want a child, they often wonder what gender the child will be - a girl or a boy.

26000 genes in 23 pairs of chromosomes

The human genetic material contains 26,000 genes, that's how many traits were coded into us during evolution. Genes are nothing more than small units of hereditary material that determine a single characteristic (eg eye color, hair color, etc.). Many people have heard of the term chromosome, but they do not know exactly what the difference is between a gene and a chromosome. All our genes are not located next to each other in a single block, but are packed into 23 pairs of chromosomes. A chromosome is nothing but a larger section of human genetic material that carries a few hundred or a few thousand genes.

Among the 23 pairs of human chromosomes, there is a pair that determines sex. This pair is called the sex chromosomes: X- and Y-chromosomes. The X-chromosome carries the female sex-determining information, and the Y-chromosome carries the male characteristics. A woman carries 2 X-chromosomes (XX), while a man includes 1 X-chromosome and 1 Y-chromosome (XY).

We always get a piece of X-chromosome from our mother. If we inherit 1 X-chromosome from the father, we will be female, while if we have 1 Y-chromosome, we will be male. This is the basic law of human sexuality. The genes on the X-chromosome and the genes on the Y-chromosome are opposites, to put it more crudely, they are each other's enemies. This is easy to accept, since the genes of the X-chromosome fight for the female gender, as opposed to the Y-chromosome, which is not the flagship of the male.

Everyone starts as a woman

Research in recent years has proven that every single fertilized egg goes in the direction of the female sex. The DAX gene on the X-chromosome controls this. However, if the Y-chromosome, or more specifically the SRY gene found on it, is present, the situation changes. The SRY gene goes into battle with the DAX gene and, defeating it, changes the sex program. The development of the male gender begins.

In the lines above, we already talked about the fact that a man carries an XY sex chromosome pair. The SRY gene on the Y-chromosome is the element of male sex. Women do not have a Y-chromosome, therefore no SRY gene. In women, the DAX gene has no counterpart, so the fertilized egg develops based on the original sexual program, i.e. the female sex is formed.

Have men been the same for 200 thousand years?

SRY is a very strange gene, because it does not carry mutations, therefore it has no gene variations (e.g. the eye color gene has several variations, from shades of brown eye color to blue and green eye color inclusive). This means that the SRY gene has not changed since our ancestor lived 200,000 years ago. The human SRY gene is significantly different from the SRY gene of male chimpanzees and also different from the SRY gene of male gorillas.

The SRY gene alone is not responsible for all male characteristics. The SRY gene is a trigger that turns on hundreds of genes on the Y chromosome responsible for male characteristics. Women who carry an XY pair of chromosomes are known to science. In these women, the SRY gene is damaged, so it cannot start the genetic program of the male sex. The genes on the Y chromosome do not start working. Since the SRY gene is damaged, the X-chromosome and the DAX gene work without disturbance. The fetus will be female. Women carrying the SRY gene defect usually have problems during puberty (e.g. lack of monthly bleeding). The reasons for this are to be found in the only one X-chromosome (instead of the normal two) and the presence of the Y-chromosome.

Genetic research that determines gender has helped us to better understand why men and women are so different. It suddenly becomes clear why the relationship between the sexes is like a minefield for people, and why men think completely differently than women.

Dr. Zsolt Nagygenetic expert

Our expert awaits your questions about genetics at [email protected]!

Recommended: