Public DNA data run through HGTScanner link Amborella to the parasitic plant Hachettea

Recovering known Amborella transfers works as a positive control ^[5][6]. It rules out a scanner that misses cases already documented in the plant. It cannot show how often the scanner calls a transfer that is not there. The account of the work gives neither the number of transfers the scan found nor its error rates.

Cai said anyone could have used the Amborella samples ^[5]. She said there previously were no tools that could identify horizontal gene transfer and pinpoint the donor and receiver ^[10]. That pairing matters here, because a scan that reported only "foreign DNA present" could not say which way the DNA moved. The paper in Methods in Ecology and Evolution describes detecting horizontal gene transfer at the fine scale using whole organelle genomes ^[4].

Cai framed the method as a different route to a familiar question. She said ^[9]:

"When such interaction is so intense, these different parties can sometimes even exchange their genetic materials, and this is how our tool can be handy."

Her own word is "sometimes." A scan can only see interactions intense enough to leave DNA behind, so a clean result would not show that two plants never interact. In our view a sequence shows only that DNA moved, and describing the living relationship takes more than that. The reversed direction of transfer ^[7] sharpens that gap.

Cohen, a postdoctoral researcher in the biology department, said that making the discovery with HGTScanner can have the same impact as making observations in the field ^[13]. She also said why the association record matters for parasitic plants ^[12]:

"In particular for parasitic plants, understanding who they're associated with, who they've associated with throughout their histories, can help us understand biodiversity at a greater scale," Cohen said, "and also maybe give us insight into who they might continue to parasitize and how that might work."