Urgent help genetics!!!?

You have a trihybrid diploid individual of genotype AaBbEe – genes A and B are on the same chromosome while E is on a different chromosome. For this individual assume the following (with lines connecting alleles on the same chromosome): A--B, a--b, E, e.

Which meiotic processes contribute to diversity in the gametes with respect to genes A, B, and E; be specific (which processes impact which genes)? Think: how do you get different combinations of the alleles in the gametes for each pair of genes - for example, Ab versus aB, or BE versus be, and so on?

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  • 1 month ago
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    1. The organism is a Trihybrid - It means it contains two different alleles to three genes AaBbEe. Here 'A' allele is from one plant and 'a' allele from the other. Together combined they became a hybrid. It follows the same for other two genes.

    2. The organism is diploid: It means organism carries Two sets of chromosomes. One from the each parent. gamete from the diploid organism is always a haploid or carry one allele.

    3. A and B are on the same chromosome: It says that A and B are on the same chromosome, as does a and b. But E and e are on different chromosomes.

    The type of gametes produced from AaBbCc with the above conditions are as follows :

    There are two cases :

    Case 1. If there is no crossing over between the chromosomes A-B and a-b. The gametes obtained are as follows :

    gametes                        E                           e

        A-B                          ABE                     ABe

         a-b                          abe                       abe

    Box:The box depicts segregation of chromosomes

    Case 2: If there is crossing over between chromosome A-B and a-b. then rearranged chromosomes will be A-b, a-B and the gametes produced are as follows :

    gametes                        E                            e

        A-b                          AbE                       Abe

        a-B                          aBE                       aBe

    Box: The box depicts segregation of chromosomes

    So, the possible gametic configuration that can be obtained in total will be :

    ABE, ABe, abe, AbE, aBE, Abe, aBe.

    Now let's validate the options :

    a. AaBbEe - not possible as the gamete cannot be in diploid condition. so this cannot exist and the right option.

    b.ABEe - not possible as the gamete will carry one gene that is either E or e. so this cannot exist and the right option.

    c.Abe - If crossing over occurs this gamete can occur. Hence this is a possible condition and not the right option.(ABE, ABe, abe, AbE, aBE, Abe, aBe.)

    d.AAbbEe- not possible as the gamete cannot be in diploid condition. so this cannot exist and the right option.

    e.aBE- If crossing over occurs this gamete can occur. Hence this is a possible condition and not the right option.(ABE, ABe, abe, AbE, aBE, Abe, aBe.)

    Therefore option a,b,d is the correct answer.

  • 1 month ago

    1.  You can get A--b and a--B from crossover in meiosis I.

    2.  Disregarding crossover for a moment, you can get ABE and ABe gametes from segregation in anaphase I.

    3.  Put 'em all together.  With various crossover and segregation, you can get these gametes:

    abe

    abE

    aBe

    aBE

    Abe

    AbE

    ABe

    ABE

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