Mammals do it too, sometimes. “The cells that make up our bodies have also not arisen gradually in the typical Darwinian manner of gene mutation and natural selection.” Some of the changes occurred by quantum leaps. Our mitochondria came aboard suddenly, deep in the past of our eukaryote or pre-eukaryote lineage, as captured bacteria. Plants acquired their chloroplasts the same way. Our genomes are mosaics. We are all symbiotic complexes, even us humans.
