Question

Отсутствие потовых желез у человека наследуется как рецессивный признак (а), сцепленный с Х-хромосомой. В семье отец и мать здоровы, а мать жены была лишена потовых желез. Составьте схему решения задачи, определите генотипы родителей, возможного потомства, пол и вероятность рождения детей, обладающих этим признаком. Решаем подробно)

Answer 1

      ХА-потовые   Ха-отсутствие
Р   ХАУ(здоров.)     х       ХАХа(здоров. но носительница, так как мать больна)
G   ХА, У                   ХА, Ха
F   ХАХА(жен.здоров.),  ХАХа(жен.здорова, но носительница), ХАУ(муж.здоров.),  ХаУ(муж.больной)
Вероятность рождения больного ребенка равна 25%

Answer 2

Problem Analysis

The problem states that the absence of sweat glands in humans is inherited as a recessive trait, linked to the X chromosome. In the family, the father and mother are healthy, while the mother of the wife is devoid of sweat glands. We need to determine the genotypes of the parents, the potential offspring, their gender, and the probability of having children with this trait.

Solution

To solve this problem, we need to consider the inheritance pattern of the absence of sweat glands and the genotypes of the individuals involved.

1. Inheritance Pattern: - The absence of sweat glands is a recessive trait linked to the X chromosome.

2. Genotypes of Parents: - Let's denote the presence of sweat glands as "S" and the absence as "s". - The father is healthy, so his genotype is "XSY" (where "Y" represents the Y chromosome). - The mother is also healthy, so her genotype is "XsXs".

3. Potential Offspring: - The potential offspring will inherit one X chromosome from the mother and one from the father.

4. Gender of Offspring: - The gender of the offspring is determined by the father's contribution, as he provides either an X or a Y chromosome.

5. Probability of Offspring with the Trait: - We can calculate the probability of having children with the absence of sweat glands using Punnett squares.

Punnett Square

Let's use a Punnett square to determine the potential genotypes and phenotypes of the offspring.

  | XSY   | XsY   |
-------------------
XsXs| XsXSY | XsXsY |
XSY | XSY   | XsY   |

From the Punnett square, we can see that: - All daughters will be carriers (XsXSY) and healthy. - All sons will inherit the X chromosome from the mother and the Y chromosome from the father, making them healthy.

Conclusion

Based on the Punnett square, the potential offspring will all be healthy carriers of the recessive trait. The sons will be healthy, and the daughters will be carriers of the trait. Therefore, the probability of having children with the absence of sweat glands is 0%.