Why Recessive Lethal Alleles Have Not Disappeared?

The article derives the probability for lethal recessive alleles in the case of recessive disadvantage or advantage. It is shown that the recessive advantage of a lethal gene can be detected by the ratio of heterozygotes and homozygotes. This demonstrates that the higher IQ of certain ethnic groups cannot be explained by the recessive advantage of lethal genes. The article shows that lethal genes can survive in the population if some lineages of families have much more children than the average.