Which chromosomal mutation doubles a portion of a chromosome?

Which chromosomal mutation doubles a portion of a chromosome?

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

Answer: (A)

Doubling a portion of a chromosome happens through duplication, where a segment is copied so a second identical copy appears in the chromosome. This increases the gene dosage for the genes in that segment and can affect how those genes are expressed. Duplication can occur during meiosis through misaligned crossing over or during DNA replication when the same region is copied more than once. The other chromosomal mutations don’t produce a doubled segment: deletion removes genetic material, reducing it; inversion flips a segment so its orientation changes without adding or removing material; translocation moves a segment to a different chromosome or to another location. Thus, duplication is the mutation that results in a doubled portion.

Doubling a portion of a chromosome happens through duplication, where a segment is copied so a second identical copy appears in the chromosome. This increases the gene dosage for the genes in that segment and can affect how those genes are expressed. Duplication can occur during meiosis through misaligned crossing over or during DNA replication when the same region is copied more than once.

The other chromosomal mutations don’t produce a doubled segment: deletion removes genetic material, reducing it; inversion flips a segment so its orientation changes without adding or removing material; translocation moves a segment to a different chromosome or to another location. Thus, duplication is the mutation that results in a doubled portion.