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Consider the following molecule of pre-mRNA:

5' Exon 1 Intron 1 Exon 2 Intron 2 Exon 3 Intron 3 Exon 4 Intron 4 Exon 5 3'

Consider two separate splice site mutations, one in one patient and the second in another patient. Patient One is homozygous for a mutation within the branch point of intron 3. Patient Two is homozygous for a mutation within the 3’ splice site of intron 4. Each of these mutations make it so splicing machinery cannot bind at the site of the specified mutation.

(A) Describe the most likely RNA molecule that would result following splicing of the pre-mRNA above for Patient One:

(B) Describe the most likely RNA molecule that would result following splicing of the pre-mRNA above for Patient Two:

(C) C). Now assume no mutations! Which of the following combinations listed below could occur in a mature mRNA as a result of alternative splicing. Circle whichever ones are possible?

A. Exon1-Exon3-Exon5
B. Exon1-Exon4-Exon5
C. Exon2-Exon4-Exon3
D. Exon3-Exon4-Exon5
E. Exon1-Exon2-Intron2