What does chromosomal translocation involve?

Chromosomal translocation specifically refers to a genetic event where a segment of one chromosome breaks off and attaches to a different, non-homologous chromosome. This can alter gene expression and function, as genes may be placed in new regulatory environments or even disrupted. Translocations can lead to various consequences, including cancer and genetic disorders, depending on the genes affected and the nature of the translocation.

The other choices pertain to different chromosomal abnormalities: the loss of a portion of a chromosome relates to deletions, splitting a chromosome into two pertains to fragmentation, and having an extra chromosome refers to aneuploidy or polyploidy. Each of these concepts is distinct from translocation and helps to highlight the unique nature of this particular chromosomal alteration.