Structural Variation

Question 1

What are the chromosomal outcomes of a pericentric inversion?

Answer 1

Pericentric inversions produce balanced and unbalanced chromosomes.

If unbalanced, there will be deletions at the ends and duplications at the ends.

Question 2

What is the memory aid for paracentric inversions?

Answer 2

A for Absent alleles.

Paracentric inversions produce balanced or dicentric chromosomes. If dicentric, the der Chr will be invisible and MISSING from progeny.

So paracentric is less severe for progeny.

Question 3

What is a paracentric inversion

Answer 3

An inversion that does not involve the centromere.

Produces dicentric or balanced chromosomes.

Question 4

What is a pericentric inversion?

Answer 4

An inversion that involves the centromere.

Pericentric inversions produce UNbalanced and balanced chromosomes.

Question 5

What is the commonly given probability of an unbalanced chromosome being produced from a pericentric inversion

Answer 5

Commonly quoted as 5-10 percent risk for unbalanced progeny per TT.

Risks vary for each inversion.

Question 6

Larger pericentric inversions have a smaller or larger del/dupe area?

Answer 6

Larger pericentric inversions produce a smaller del/dupe region on the derivative chromosome.

So smaller inversions have a more severe outcome!

Question 7

What is the memory aid for pericentric inversions?

Answer 7

I for Involves the centromere.

Pericentric inversions can produce balanced OR unbalanced chromosomes with deletions and duplications at the terminal ends.