Lecture 12 - Chromosome Variation II

Question 1

What are the types of aneuploidy?

L12 S36

Answer 1

Nullisomy:
-loss of both members of a homologous pairs (2n-2)

Monosomey:
-loss of a single chromosome (2n-1)

Trisomy:
-gain of a single chromosome (2n+1)

Tetrasomy:
-gain of two homologous chromosomes (2n+2)

Question 2

Why in humans and mammals are sex chromosome aneuploidy more common than autosomal aneuploids?

L12 S49

Answer 2

There is a doseage compensation mechanism for sex chromosomes but not for autosomes. This typically results in spontaneous abortion of autosomal aneuploids.