In an creationist article, about molecular virologist, Dr Yingguang Liu, it says:
Evolutionists commonly invoke ‘duplication’ as a way to create brand new genes. A copying error can lead to an extra copy of a gene, which supposedly can then go on to evolve into something else (‘neofunctionalization’) without compromising the original gene. Dr Liu discussed what happens after a theoretical duplication, and the picture was not pretty for evolution. [reference 1] First of all, degeneration is expected, because a non-important (‘neutral’) gene can freely mutate or even be deleted with no threat to the organism. With no selection pressure to maintain the gene, the opportunity for neofunctionalization is quite limited. Also, the main difference between the various forms of life is how genes are regulated, not the number of genes. Gene duplication does not help evolutionary theory.
Are some new genes created through the mechanism of gene duplication?