A mutation in the Pitx1 gene prevents normal hindlimb formation in mouse embryos. Analyses of the presence and length of the gene, its mRNA transcript, and the protein produced show the following results: DNA sequence: normal length mRNA: present, normal length protein: present, shorter than normal Which of the following is the most likely explanation for the mutation? a. The mutation removes a transcription factor binding site in a cis-regulatory region of Pitx1. b. It is a nonsense mutation in the Pitx1 coding region that changes a codon for an amino acid into a stop codon. c. It is a missense mutation in the Pitx1 coding region that changes a single amino acid. d. It is a mutation in an enhancer that prevents a transcription factor from binding..

1. A mutation in the Pitx1 gene prevents normal hindlimb formation in mouse embryos. Analyses
of the presence and length of the gene, its mRNA transcript, and the protein produced show the
following results:
DNA sequence: normal length
mRNA: present, normal length
protein: present, shorter than normal
Which of the following is the most likely explanation for the mutation?
a. The mutation removes a transcription factor binding site in a cis-regulatory region of Pitx1.
b. It is a nonsense mutation in the Pitx1 coding region that changes a codon for an amino acid
into a stop codon.
c. It is a missense mutation in the Pitx1 coding region that changes a single amino acid.
d. It is a mutation in an enhancer that prevents a transcription factor from binding.