Gene duplication is a biological process where a segment of DNA containing a gene is copied, resulting in two identical genes. This can occur during DNA replication or through errors in cellular processes. The duplicated gene can evolve over time, potentially leading to new functions or traits in an organism. This mechanism is significant in evolution, as it provides raw material for genetic diversity. When one copy of the gene retains its original function, the other can undergo mutations and adapt to new roles. This process has contributed to the complexity of many organisms, including humans, by allowing for the development of new proteins and functions.