Curious Amanda

Society often refers to the genetic problems caused by inbreeding. It is true that an excessive proliferation of bad genes increases the risk of genetic diseases and reduces an individual's selective value. However, science has questioned certain preconceived opinions and has shown that inbreeding also offers many benefits for the genetics of a population.

Low risk of genetic disorders: Children from a mother-son couple are twice as likely to inherit genetic abnormalities as children from a couple with no family ties. This may seem significant, but it should be remembered that the risk of genetic abnormalities in children from unrelated couples is 2-3%, so it is only 4-6% for children from a mother-son couple, which is very negligible. In other words, a mother and her son have a 94-96% chance of having healthy children.

Genetic purging: When bad genes are expressed among offspring, natural selection eliminates the most disadvantageous individuals. In this way, it causes a purification of the family's genetic heritage, and therefore an improvement in the selective value of individuals.

Heterosis: This is the phenomenon produced by the crossing of two inbred lines. Individuals have more vigorous offspring for two reasons: the genetic purging caused by the inbreeding of their parents and, consequently, the union of these two pure lines, which adds new genes to their offspring, preventing excessive loss of genetic diversity.

Natural selection: A person shares 50% of their DNA with their offspring. A mother shares 50% of her genes with her son, 25% with her grandchildren, and 12.5% with her great-grandchildren. As we can see, the genes passed on decrease rapidly over generations. On the contrary, a mother who reproduces with her own son will share 75% of her DNA with her inbred children. Assuming that the daughters resulting from this union reproduce with their own sons (whom they will have had with an unrelated man), the mother will share 56.25% of her genes with her inbred grandchildren and 42.20% with her inbred great-grandchildren. That is why, from an evolutionary perspective, a mother would be better off breeding with her son.