Which chromosomal aberration is characterized by moving a segment to a nonhomologous chromosome?

Which chromosomal aberration is characterized by moving a segment to a nonhomologous chromosome?

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

Answer: (C)

Translocation is a chromosomal rearrangement in which a piece of one chromosome breaks off and attaches to a nonhomologous chromosome. This interchromosomal transfer—the segment moving to a different chromosome that is not its partner—defines the event. There are two main forms: reciprocal translocation, where segments are exchanged between two chromosomes, and nonreciprocal translocation, where a piece moves to another chromosome without an exchange. This differs from a deletion, where a segment is lost from a chromosome; a duplication, where an extra copy of a segment is present; and an inversion, where a segment is reversed in orientation within the same chromosome. Translocations can be balanced, with no net gain or loss of genetic material and often no phenotype, or unbalanced, with missing or extra genes that can cause developmental problems or disease. A well-known example is the Philadelphia chromosome, a reciprocal translocation between chromosomes 9 and 22 that creates a fusion gene driving some leukemias.

Translocation is a chromosomal rearrangement in which a piece of one chromosome breaks off and attaches to a nonhomologous chromosome. This interchromosomal transfer—the segment moving to a different chromosome that is not its partner—defines the event. There are two main forms: reciprocal translocation, where segments are exchanged between two chromosomes, and nonreciprocal translocation, where a piece moves to another chromosome without an exchange. This differs from a deletion, where a segment is lost from a chromosome; a duplication, where an extra copy of a segment is present; and an inversion, where a segment is reversed in orientation within the same chromosome. Translocations can be balanced, with no net gain or loss of genetic material and often no phenotype, or unbalanced, with missing or extra genes that can cause developmental problems or disease. A well-known example is the Philadelphia chromosome, a reciprocal translocation between chromosomes 9 and 22 that creates a fusion gene driving some leukemias.