Huntington Disease Is Caused by Expansion of the Trinucleotide Repeat

Multiple Choice

Huntington disease is caused by expansion of the trinucleotide repeat region of the HD gene that results in the production of a Huntingtin protein with an expanded number of glutamines.An animal model with most features of this syndrome could be created by

A) adding a transgene containing a disease-causing mutant allele of the HD gene to a mouse or primate genome.
B) adding a transgene containing a wild-type copy of the HD gene to a mouse or primate genome.
C) knocking out both copies of the HD gene from a mouse or primate genome.
D) knocking out one copy of the HD gene from a mouse or primate genome.