How are new genes created?
From the mutation of existing genes only
From the duplication, and then the mutation of existing genes
From a different species
From duplicating existing genes
and recombining them in a new way, or by horizontal gene transfer from a different species.
New genes can be created through a process called gene duplication, followed by mutation. Gene duplication occurs when a segment of DNA is copied within the genome. This can happen through various mechanisms such as replication errors or recombination events. Once a gene is duplicated, the duplicate copy is free to accumulate mutations over time without affecting the function of the original gene. These mutations can alter the sequence of the duplicated gene, leading to the emergence of a new gene with a different function.
Over time, these new genes can acquire new functions through further mutations and adaptations. This process is known as gene evolution or neofunctionalization. The duplicated gene may undergo different mutations, such as point mutations, insertions, deletions, or rearrangements, which can change its coding sequence or regulatory elements. These changes can result in new protein functions or altered gene expression patterns.
It is important to note that new genes can also be acquired through horizontal gene transfer, where genes are transferred between different species. However, gene duplication followed by mutation is a primary mechanism for the emergence of new genes within a species.