Mendelian Genetics

Example Question:

We will do only one question to tell you the easy way of answering the question. You can than study it and work out the given question yourselves. 

We believe and had been taught to break down questions while answering it. That is what we will do here. We will answer the question step by step.

Example Question:

Law of Segregation:

Two true breed pea plants were crossed, one was tall and the other was dwarf. The F1 generation had all Tall plants.Show the monohybrid cross of the two plants.

First think you do when you read a question is to underline the key words. You will notice this has been done above.

Now determine which trait is dominant.
  • Because the F1 generation is all Tall plants, the tall trait is dominant.

Now that we know which trait is dominant we can determine the genotype of the parents.
  • Lets assign the traits a letter.

                       Tall - T (since it is dominant)
                       Dwarf - t (since it is recessive)

  • Since the parents are pure breed it has to be homozygous.

               Phenotype: pure breed tall        X        pure breed Dwarf
               Genotype:       TT                                     tt

  • Note: TT is Homozygous dominant and tt is homozygous recessive.

Now you separate the alleles to get the gametes.

                         TT will give T gamete.                       
                         tt will give t gamete.

Now make a punnett square.

  • Note that the question says Monohybrid Cross.                                                    

The monohybrid cross shows that the cross between a Tall and a dwarf plant results in the F1 generation as all Tall plants.

The question is answered.

You will notice that when you use step by step way of answering a question you will never miss out any important point.


For the electronic copy of the example question and solution, download it from the click below.
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If you click on the video below you can watch a quick tutorial on Mendel's Genetics.
It can help you understand better on how to approach Mendel's application Questions. 

 This video has been taken from youtube.

Now that you now how to approach a Mendel's Genetics question lets do some exercise question.

Click on the next page icon to view the exercise questions.

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