The structure in the nucleus of each of our cells that carries genetic information.
Chromosomes are made up of DNA wrapped around proteins called histones. True carriers of genetic information, they contain the genes that define our biological characteristics and contribute to the proper functioning of the organism.
In humans, each cell has 46 chromosomes organized into 23 pairs. Twenty-two of these, called autosomes, are common to both sexes. The last pair, the sex chromosomes (XX in women and XY in men), determine sex.
The central role of chromosomes
Beyond carrying DNA, chromosomes ensure the faithful transmission of genetic information during cell division. They guarantee that each new cell will inherit a complete and identical heritage. This mechanism is essential for embryonic development, growth, tissue repair and all of our vital functions.
The sex chromosomes
The sex chromosomes, marked X and Y, are special because they condition sexual development. Women have two X chromosomes (XX) while men have one X and one Y chromosome (XY). The Y chromosome contains genes essential for male differentiation, including the SRY gene, which triggers testicular development. The larger and more gene-rich X chromosome carries a great deal of information that is essential not only for sexual development, but also for brain and metabolic functions. Some genetic diseases, known as X-related diseases, affect men more frequently because they have only one copy of this chromosome.
The X chromosome
The X chromosome carries the genes that determine female sex. It is the 23rd pair of chromosomes with another X chromosome. The daughters have two X chromosomes, one from the mother and one from the father.
The Y chromosome
The Y chromosome carries the genes that determine the male sex. It is the 23rd pair of chromosomes with the X chromosome. Boys have an X chromosome and a Y chromosome.
Chromosomes and health
Any chromosomal abnormality can have important consequences. For example, an extra copy of chromosome 21 is responsible for trisomy 21. Other alterations, such as deletions or chromosomal rearrangements, may be involved in neurological, psychiatric or some rare genetic disorders.
Neuroscience research is focusing on these abnormalities to better understand their role in brain development and cognitive function. Advances in sequencing and genetic imaging techniques are now paving the way for more accurate diagnostics and innovative therapeutic approaches.
Other Words That May Be of Interest to You
- Deoxyribonucleic acid (DNA) :
- Deoxyribonucleic acid (DNA) contains all the genetic information, known as the genome, that enables living organisms to develop, function and reproduce.
- RiboNucleic Acid (RNA) :
- A copy of DNA called a transcript, RNA enables the transport of genetic information and the process of protein synthesis.