What happens in Duplication?

Answer 1

Deletions and duplications of single-base pairs typically arise during homologous recombination and cause diseases. But what happens when a mutation occurs over multiple genes?

Rearrangements of chromosomes include deletions of DNA sequences and duplications of segments, both of which can encompass thousands to hundreds of thousands of bases. Why do these large rearrangements occur? For one, certain structural features of the genome, also referred to as genome architecture, can render various regions fragile and thus prone to events such as chromosome breakage, which often result in translocations, deletions, and duplications. Often, these alterations happen due to errors during cell division when chromosomes align (Figure 1). Homologous recombination between areas of concentrated repeated sequences frequently creates deletions and duplications. Because they commonly involve more than one gene, the disorders caused by these large deletion and duplication mutations are often severe.