People affected by Fragile X syndrome have a chromosome that is prone to breaking because the DNA at one site is
A) methylated.
B) unstable.
C) increased.
D) reduced.

Question

Quizplus · Accepted Answer

Fragile X syndrome is caused by a mutation in the FMR1 gene on the X chromosome. The mutation is a triplet repeat expansion of CGG, which causes the DNA to be unstable and prone to breaking. As a result, individuals with Fragile X syndrome have a chromosome that appears "fragile" under the microscope.

People Affected by Fragile X Syndrome Have a Chromosome That