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It all starts when the sperm and egg fuse to give birth to an embryo whose cells have 46 chromosomes, half from the mother and half from the father, each one being a part of the cell nucleus made up of long DNA molecules. 1 This DNA is composed of 1% of genes with one maternal and one paternal copy. Only the pair of chromosomes known as sex chromosomes is different between men and women, the rest of its DNA is made up of 99% of gene sequence factors, elements that regulate genes. These genes determine a number of physical characteristics of the child, such as eye color, hair, skin and facial features. In each generation, there is an intermingling of genes: half from one parent, half from the other, which means that a quarter comes from the grandparents, but there are dominant traits and other, weaker recessive traits. 2
Genes also greatly influence the health of the embryo. When there is an abnormality in the factors making up DNA, pathologies appear, influenced by epigenetics (the mechanism controlling the expression of genes). 2
Thus, parents transmit to their children a set of innate characteristics "ranging from the skin and eye color to certain so-called family diseases". This information, which is engraved in the marble of our DNA, of our chromosomes, represents the "hardware" and is transmitted by genes from one generation to the next. 2
Dr. Siba Saade
Pediatrician
