In a family where both parents had normal vision and had one dark and the other blond hair, a child with blond hair was born. What is the likelihood of myopic children with dark hair appearing in a family? It is known that dark hair dominates light hair, and myopia is a recessive sign.
A – dark hair;
a – blonde hair;
B – normal vision;
b – myopia.
According to the conditions of the problem, it is known that parents with dark and light hair gave birth to a child with light hair. Therefore, for such a child to be born, it is necessary that one of the parents be a carrier of the gene with blond hair.
R: AaBb * aaBb
F1: AaBB – dark hair and normal vision, 2AaBb – dark hair and normal vision, Aabb – dark hair and myopia, aaBB – blonde hair and normal vision, 2aaBb – blonde hair and normal vision, aabb – blonde hair and myopia.
Therefore, the probability of having myopic children with dark hair is 1/8 = 12.5%.
One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.