Chromosomal Abnormalities

Question 0

4 types of unbalanced structural chromosomal rearrangement

Answer 0

1. Deletion
2. Duplication
3. Ring chromosomes
4. Isochromosomes

Question 1

3 types of balanced structural rearrangement

Answer 1

1. Inversion
2. Reciprocal translocation
3. Robertsonian translocation

Question 2

Most chromosomal rearrangements are a result of a random event or due to a chromosomal anomaly inherited by parents?

Answer 2

Random, and unlikely to occur again

Question 3

Can you have a diccentric ch?

Answer 3

No, inviable, can’t segregate with 2 centromeres (2 diff ch fused end to end)

Question 4

What would happen if crossing over occurs outside of inverted region?

Answer 4

No abnormal gametes formed.

Abnormal gametes are only found phenotype xing over occurs within inverted regions, which can lead to duplication and deletions

Question 5

Reciprocal translocation

Answer 5

Breakage and rejoining of nonhomologous ch. with a reciprocal exchange of broken segments

Question 6

Quadrivalent figure is formed when?

Answer 6

When nonhomologous ch. of a carrier of a balanced reciprocal translocation pair at meiosis

Question 7

3 segregation patterns of reciprocal translocation

Answer 7

Alternative (normal and balanced)
adjacent 1(unbalanced)
adjacent 2 (unbalanced)

Unbalanced could lead to partial trisomy/disomy

Question 8

Robertsonian translocation

Answer 8

Fusion of 2 acrocentric chromosomes, resulting in loss of both short arms and loss in chromosome # (but still balanced)

Question 9

Unequal crossing over and abnormal segregation can result in which 2 unbalanced chromosomal segregation?

Answer 9

Deletion and duplication

Question 10

Isochromosomes

Answer 10

Abnormal ch with 2 identical arms (2p or 2q) due to it losing one of its arms

Question 11

List 2 ways that duplication can occur in unbalanced structural rearrangement

Answer 11

1. unequal crossing over

2. abnormal segregation during meiosis in a carrier of translocation or inversion