We don’t fully understand the mechanism of horizontal gene transfer (HT). If there is HT between host and donor, it would like be transposable elements. And we don’t really understand how genetic information not only escapes the nucleus and cellular membrane of one cell, then transports through the extracullular matrix (ECM) (or vasculature?) to another cell, penetrates the cell membrane, and then navigates to the nucleus, and embeds itself in the other-origin cell… all without being degraded by nucleases that are designed to prevent free-floating nucleic acids (RNA and DNA). 🤷