In humans, the gene for right-handedness (A) dominates over the gene for left-handedness (a). A right-handed woman marries a right-handed man. It is known that both fathers were left-handed. Determine the genotypes of all family members on the basis of “right-handedness / left-handedness condition”. What is the probability of the birth of left-handers in this family?
1. Genotypes and phenotypes P: both mother and father – Aa – t. it is indicated that their fathers are left-handed (aa), which means that one gamete (a) both receive from their fathers.
2. Genotypes and phenotypes of offspring: AA and Aa – right-handed children 75% and aa – left-handed 25%;
3. The probability of giving birth to left-handed children is 25%.
Answer: mother – Aa, father – Aa, probability – 25.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.