Reference no: EM133619803
Reading Genetics Problems: EC Assignment
Reading and answering genetics problems requires practice. It also requires you to be able to pull information out of the question, to determine what information you need and what you don't, and to figure out what the question wants you to do.
This assignment is going to help you learn to do that (I hope) and at the very least will earn you up to an additional 5% on your second lowest test grade.
The steps to mastering a question are generally as follows:
- Read the question and make note of any useful information. It might help you to underline the information.
- Rewrite any useful information so that you don't have to search for it again.
- Perform whatever calculation is required to answer the question.
- Make sure that your answer is in the correct format (i.e. # of individuals, probability, ratio, percentage, etc.)
Let's look at a few examples:
Question 1:
If two parents are heterozygous for a genetically inherited dominant trait, what is the probability that they will have a child together who has this trait in his or her phenotype?
That seems short but there is a lot to unpack. Let's see what information we can find.
Unpacking the question:
Two parents are heterozygous for a genetically inherited dominant trait that causes dwarfism. What is the probability that they will have a child together who has this trait?
Yellow: We know that we have two parents and both are heterozygous.
Teal: We know that the trait that they are heterozygous for is a dominantly expressed trait; this means that one copy of the trait is sufficient for the person to show the phenotype. As such, both parents have the phenotype.
Green: We know that they both have dwarfism. This is kind of useful, but it is not required information.
Pink: The question wants us to answer with a probability. That probability should be the likelihood of having dwarfism (the trait).
Rewriting what we know in a useful format:
In order to solve this question, it would be helpful to assign some alleles to make it easier to write out our genotypes. We can pick whatever we want, but I'm going to pick the letter D for the dominant trait and d for the recessive trait.
D = Dwarfism
d = normal height