Which chromosomal mutation results in extra copies of parts of a chromosome?

Which chromosomal mutation results in extra copies of parts of a chromosome?

• A. Inversion chromosomal mutation
• B. Duplication chromosomal mutation
• C. Translocation chromosomal mutation
• D. Deletion chromosomal mutation

Answer: (B)

Duplication mutations create extra copies of a chromosome segment, so there are more copies of the genes in that region than normal. This happens when misalignment during meiosis or a replication error copies a segment and leaves an extra duplicate on the chromosome. The result is increased gene dosage, which can affect how much of those genes are expressed. Inversions flip a segment within the same chromosome but don’t change the number of copies. Translocations move a segment to a different chromosome, also without increasing copy number. Deletions remove a segment, reducing the number of gene copies. So the mutation that yields extra copies is the duplication.

Duplication mutations create extra copies of a chromosome segment, so there are more copies of the genes in that region than normal. This happens when misalignment during meiosis or a replication error copies a segment and leaves an extra duplicate on the chromosome. The result is increased gene dosage, which can affect how much of those genes are expressed.

Inversions flip a segment within the same chromosome but don’t change the number of copies. Translocations move a segment to a different chromosome, also without increasing copy number. Deletions remove a segment, reducing the number of gene copies. So the mutation that yields extra copies is the duplication.