In the context of chromosomal rearrangements, what is the most accurate description of what happens when a piece of DNA is missing from a chromosome?

• A. A deletion occurs, removing one or more genes from the chromosome, which can change gene dosage and phenotype.
• B. An inversion occurs, reversing the orientation of a chromosomal segment without changing the total amount of DNA.
• C. A duplication occurs, producing an extra copy of a chromosomal segment and increasing gene dosage.
• D. A balanced reciprocal translocation occurs, exchanging segments between nonhomologous chromosomes without net loss of DNA.

Answer: (A)