Final answer:
A translocation mutation occurs when segments from two different nonhomologous chromosomes are exchanged during DNA replication, which can have significant genetic consequences.
Step-by-step explanation:
Mutation Type Caused by Chromosome Segment Exchange
When large fragments from two nonhomologous chromosomes, in this case, chromosome #4 and #15, are erroneously exchanged during DNA replication, the mutation is referred to as a translocation. A translocation is a type of chromosomal mutation where a large segment of one chromosome breaks off and attaches to a different chromosome. These exchanges can lead to serious phenotype changes and are sometimes lethal. Translocations can occur during erroneous DNA replication processes such as those that happen in the S phase of cell division, whether in mitosis or meiosis.
They are different from point mutations, which usually involve only single nucleotides. The correct identification and understanding of these mutations are essential since they can have significant genetic consequences for the organism.