Anonymous
Anonymous asked in Science & MathematicsBiology · 5 months ago

Genetics Homework Questions?

1. What is the probability of parents having six children, five male and one female?

2. Albinism is a trait that is autosomal recessive. If two parents who are carriers have two children, what is the probability that one will be normal and the other will be albino?

If possible, please explain or show the calculations. Thank you.

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  • 5 months ago

    1. The probability for each child being a male or a female is ½. For five children, you would multiple by ½ five times, giving you 1/32. Because we are not assuming the order of the children, for example the first child being a female and the other four being males, we need to multiple 1/32 by 5. 

    This gives us our final answer of 5/32.2. The probability of two carriers having a normal child is ¾. Let’s say each parent has a genotype of Aa. A normal child will either have the genotype AA or Aa. There are three possibilities to have a normal child: 1) both parents give A; 2) mom gives A and dad gives a; or 3) mom gives a and dad gives A. For option 1, each parent has ½ of a chance of giving A. ½ * ½ = ¼.For option 2, mom has a ½ chance of giving A and dad has a ½ chance of giving a. ½ * ½ = ¼.For option 3, mom has ½ a chance of giving a and dad has ½ a chance of giving A. ½ * ½ = ¼.Since these events are all mutually exclusive, we add the final probabilities together: ¼ + ¼ + ¼ = ¾ chance of the child being normal.For a cystic child, the genotype must be aa. The only way for this to happen is if both parents give aa. Each parent has a ½ chance of giving an a. ½ * ½ = ¼.Again, as in question 1, we are not assuming the order of which child is born first – the normal one or the affected one. So, we multiple ¾ and ¼ by 2.2* ¼ * ¾ = 6/16, which is our final answer.

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  • 5 months ago

    1. There is 1/2 chance that it's a male or female every time.

    Since they have 6 children, you have to multiply 6 by 1/2. Therefore, there is a possibility of 3 that they have 5 males and 1 female.

    2. There is a 1/2 chance of albinism for every child they have. 

    Since they have 2 children, you have to multiply 2 by 1/2.  Therefore, there is a possibility of 1 that 1 is albinos and one is not.

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