Question: 9. The normal configuration of a plant chromosome, N3 is: The letters indicate genes and the numb…

9. The normal configuration of a plant
chromosome, N3 is:

The letters indicate genes and the numbers indicate the
distances between each pair of adjacent genes. A plant is found
with a chromosome aberration R3 as shown
below:

The differently shaded area of the image indicates the region
affected by the rearrangement. The lines show the breakpoints and
the numbers below the image indicate the exact positions in map
units, of the breakpoints.

I) This rearrangement is a:

a) Balanced reciprocal translocation.

b) Mess.

c) Paracentric Inversion.

d) Pericentric Inversion.

e) Robertsonian translocation.

II) If an individual were
homozygous for the R3 chromosome, how
would the map distance between A and G be affected? (2
points)

a) It would be reduced to 0

b) It would be reduced to 8 mu.

c) It would be unaffected.

d) It would be increased to 27 mu

e) It would increase so that the genes behaved as unlinked
genes.

III) If an individual were heterozygous for the N3/R3
chromosomes, what might we expect to see during meiosis
I?

a) Dicentric bridges

b) Acentric fragments

c) A looped configuration of the paired homologues

d) A cross, or X shaped configuration of paired homologues.

e) No pairing at all of the homologues.