The human population is afflicted by a large number of lethal genetic diseases. Professor Carlos Eduardo Guerra Amorim tried to understand the reason. Why did evolution not eliminate all lethal genetic abnormalities?

In the case of recessive illness, one who inherits only one copy of the defective gene remains healthy. For the disease to manifest, you must inherit the copy of the gene from both parents. Many lethal diseases are transmitted in this way and geneticists do not understand why these mutations continue to exist.

In the study in question, the researchers selected 417 mutations in 32 genes. Mutations are recessive and result in lethal genetic diseases, such as cystic fibrosis and Tay-Sachs disease. The researchers compared how often mutations occur and how often disappear by natural selection. Comparing the result with current sick individuals, they found that mutations should be more common than expected

Why does nature leave potentially lethal mutations in human genetic code? Researchers hypothesize that the benefits associated with these mutations are greater than the disadvantages. In addition, it is more common to transmit only one recessive gene than the lethal couple. There are no reliable answers. Understanding the possible motivations, however, would help identify the mutations better and fight them.

Source: medicalxpress.com