Horizontal genome transfer as an asexual path to the formation of new species : Nature : Nature Publishing Group

Allopolyploidization, the combination of the genomes from two different
species, has been a major source of evolutionary innovation and a driver
of speciation and environmental adaptation.
In plants, it has also contributed greatly to crop domestication, as
the superior properties of many modern crop plants were conferred by
ancient allopolyploidization events.
It is generally thought that allopolyploidization occurred through
hybridization events between species, accompanied or followed by genome
duplication.
Although many allopolyploids arose from closely related species
(congeners), there are also allopolyploid species that were formed from
more distantly related progenitor species belonging to different genera
or even different tribes.
Here we have examined the possibility that allopolyploidization can
also occur by asexual mechanisms. We show that upon grafting—a mechanism
of plant–plant interaction that is widespread in nature—entire nuclear
genomes can be transferred between plant cells. We provide direct
evidence for this process resulting in speciation by creating a new
allopolyploid plant species from a herbaceous species and a woody
species in the nightshade family. The new species is fertile and
produces fertile progeny. Our data highlight natural grafting as a
potential asexual mechanism of speciation and also provide a method for
the generation of novel allopolyploid crop species.