Question

Consider two non-homologous chromosomes whose normal sequence of segments and centromere locations are shown here. What kind of changes are these? I think it's a translocation and i cannot tell what the second one is.

Question 7: (2 points) Consider two non-homologous chromosomes whose normal sequences of segments and centromere locations are shown here. Chromosome 1 A B C D E F G H Chromosome 2 O R . S T U V Determine the type (or types) of chromosomal structural changes necessary to produce the following chromosomes. a. S T U V D E F G H b. A B VTED C QR. SF G H Note: You have to be specific. For example, it is not enough to say a deletion and then a pericentric inversion. You have to include the exact genes involved in the chromosomal aberrations. For example, deletion of FG from chromosome 1, then a reciprocal translocation of AB and OT between the two chromosomes, etc.

Answer 1

A)

This involves a deletion of one arm of Chromosome 1 (deletion of the A-B-C loci) followed by a Paracentric inversion on Chromosome 2,which flipped the orientation of the S-T-U-V loci about the centromere. Finally, a non-reciprocal translocation of the inverted arm of Chromosome 2 to the deleted arm of Chromosome 1.

B)

The chromosomal changes necessary to produce the given chromosomes are:

1. Deletion of U locus from Chromosome 2.
2. Reciprocal translocation between the two chromosomes that exchanges the (F-G-H) segment from Chromosome 1 with the (T-V) segment from Chromosome 2.
3. Pericentric Inversion of Chromosome 1, involving the segment from locus C to V. This changes the arrangement of Chromosome 1 from A-B-C-Centromere-D-E-T-V to A-B-V-T-E-D-Centromere-C.