AP BIOLOGY

HEREDITY

MUTATIONS

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
A mutation that occurs in an intron could impact the organism depending on the type of mutation
A
True
B
False
Explanation: 

Detailed explanation-1: -If a point mutation occurs within an intron of a coding gene, it does not cause any change in the coded message, but may result in a defect in RNA splicing and in this way could also affect the resulting protein.

Detailed explanation-2: -Here we review evidence from mRNA analysis and entire genomic sequencing indicating that pathogenic mutations can occur deep within the introns of over 75 disease-associated genes.

Detailed explanation-3: -The intron sequences that affect mRNA accumulation are redundant and dispersed, so a point mutation or even a large deletion in the intron would probably not significantly reduce the expression of the gene unless splicing was disrupted.

Detailed explanation-4: -As mutations in introns do not affect protein sequences, they are usually ignored when looking for normal or pathogenic genomic variation. However, introns comprise about half of the human non-coding genome and they can have important regulatory roles.

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