Peperomia is a type of flowering plant called an angiosperm. They have also found that 48 other angiosperms have acquired this cox1 gene via 32 different horizontal gene transfers. Next they separated the pieces using something called Southern Blotting Technique. Researchers of the department of genetics at the University of Georgia have also found that a horizontal gene transfer has occurred at the copia long terminal repeat retrotransposon between Drosphila melanogaster and Drosphila willistoni . D. melanogaster and D. willistoni are both types of fruit flies.
Bacteria definitely undergoes horizontal gene transfer.
Molecular Biologists at the University of California have studied the transfer and have found that operational genes have been horizontally transferred continuously. They also have found that over time operational genes have been transferred more than informational. Recently a transposon called mariner has transferred into the human genome. Horizontal Gene Transfer's Dangers Horizontal gene transfer can cause new bacteria and new viruses that can be antibiotic resistant. New diseases can result from new viruses and bacteria being formed, which we may not have medicines to treat.