Chimeric genes can also form through Ectopic recombination, where there is an exchange between portions of the genome that are not actually related.
[2] A naturally occurring example of this is a chimeric gene called "Booster", which boosts photosynthesis in poplar trees.
However, in some cases, these new peptides can form fully functional gene products that are selectively favored and spread through populations quickly.
[5] The new amino acid residues that it recruited from yellow emperor allow the new protein to act on long chain alcohols and diols, including growth hormones and pheremones.
In this case, the combination of different protein domains resulted in a gene that was fully functional and favored by selection.