How does convergent evolution occur, given the improbability of finding even one functional gene in sequence space, let alone the same gene arising twice independently? No one knows exactly, but perhaps it was a “fortuitous juxtaposition of suitable sequences,” or “positive selection,” or “de novo origination.” Need to explain two similar genes in more closely related lineages? Try “gene duplication,” or “chimerical gene fusion,” or “retropositioning,” or “extensive refashioning of the genome,” or some other scientific-sounding combination of words.
