Why can DNA be transferred between organisms?

• A. Genetic code is universal and so are the transcription and translation factors
• B. DNA is unable to be transferred between different species due to compatibility
• C. Only identical genomes can be transferred between organisms
• D. Transfer is driven by photosynthesis

Answer: (A)

The ability to transfer DNA between organisms rests on a nearly universal genetic code and shared transcription and translation machinery. Because the codons in the genetic code map to the same amino acids in almost all living things, a gene from one organism can be read by the host’s cellular machinery and translated into a functional protein. While regulatory sequences may need tuning so they’re recognized by the host, the basic process of transcribing DNA into RNA and translating that RNA into protein works across diverse species. This universality is what makes genetic engineering across different organisms possible, such as expressing a human gene in bacteria.

The other statements don’t fit because DNA transfer between species does occur, often with assistance from vectors or natural processes; genomes don’t have to be identical for transfer to happen; and photosynthesis doesn’t drive DNA transfer.