Question

^{If you could please provide a drawing of how this would look like, i am a bit confused.}

*Consider a diploid cell that contains three pairs of chromosomes designated AA, BB, and CC. Each pair includes a maternal and a paternal member (e.g., A^m and A^p.)

After meiosis I, assuming no crossing over, what combinations of chromosomes are possible in the two product cells? Select all that apply.

After meiosis I, assuming no crossing over, what combinations of chromosomes are possible in the two product cells? Select all that apply.

Am, Bp, Cp

Am, Bm, Cp

Am, Bp, Cm

Ap, Bp, Cm

Ap, Bm, Cp

Am, Bm, Cm

Ap, Bp, Cp

Ap, Bm, Cm

Answer 1

Solution:

It is given that the parent cell has three chromosomes, A, B and C with one copy each from maternal and paternal side.

Chromosomes in the parent cell are thus:

AmAp, BmBp, CmCp.

We know, during meiosis chromosomes separate randomly to daughter cells. This means,a daughter cell may inherit either of the maternal or paternal copy of a particular chromosome from parent cell.  

Daughter cell may inherit either :

1)Am or Ap,

2) Bm or Bp, and

3) Cm or Cm.

Thus, there are two possibilities for each chromosome. Since there are three chromosomes, total number of possibilities or combinations which a daughter cell may inherit is

=2*2*2

=8

The possibilities are :

1) AmBmCm (all maternal copies)

2)AmBmCp (maternal A and B and paternal C)

3)AmBpCm (maternal A and C, but paternal B )

4)ApBmCm (maternal B and C , but paternal A)

5)ApBmCm (paternal A, but maternal B and C)

6)ApBpCm (paternal A and B, but maternal C)

7)AmBpCp (maternal A, but paternal B and C)

8)ApBpCp (all paternal)

Thus, all are actually correct choices:

Am, Bp, Cp

Am, Bm, Cp

Am, Bp, Cm

Ap, Bp, Cm

Ap, Bm, Cp

Am, Bm, Cm

Ap, Bp, Cp

Ap, Bm, Cm