What about the DNA evidence?

[stevevw]

It shows that the BovB DNA retrotransposon might have come from snakes, but the insertions are still species specific. This is not unlike the ERV evidence. These jumping genes can be moved from species to species just like a virus. Once in the new species they copy themselves and start inserting all over the place. By comparing the sites of insertions we can determine if they were inherited vertically or horizontally.

More importantly, this is nothing like functional genes involved with larger morphological and physiological features moving willy-nilly between genomes. We are talking about retroviruses and retrotransposons whose primary funciton is just to copy themselves.


I would focus on that paragraph.



Yeah, they are. We are able to tell the difference bewteen HGT and VGT, and the VGT DNA matches the hierarchy we would expect to see.

I can understand a tick transferring them from say a snake to a cow but how does this happen with a sea urchin and zebrafish which live in the water.