<P> As Jian, Rivera and Lake (1999) put it: "Increasingly, studies of genes and genomes are indicating that considerable horizontal transfer has occurred between prokaryotes" (see also Lake and Rivera, 2007). The phenomenon appears to have had some significance for unicellular eukaryotes as well . As Bapteste et al. (2005) observe, "additional evidence suggests that gene transfer might also be an important evolutionary mechanism in protist evolution ." </P> <P> Grafting of one plant to another can transfer chloroplasts (organelles in plant cells that conduct photosynthesis), mitochondrial DNA, and the entire cell nucleus containing the genome to potentially make a new species . Some Lepidoptera (e.g. monarch butterflies and silkworms) have been genetically modified by horizontal gene transfer from the wasp bracovirus . Bites from the insect Reduviidae (assassin bug) can, via a parasite, infect humans with the trypanosomal Chagas disease, which can insert its DNA into the human genome . It has been suggested that lateral gene transfer to humans from bacteria may play a role in cancer . </P> <P> Richardson and Palmer (2007) state: "Horizontal gene transfer (HGT) has played a major role in bacterial evolution and is fairly common in certain unicellular eukaryotes . However, the prevalence and importance of HGT in the evolution of multicellular eukaryotes remain unclear ." </P> <P> Due to the increasing amount of evidence suggesting the importance of these phenomena for evolution (see below) molecular biologists such as Peter Gogarten have described horizontal gene transfer as "A New Paradigm for Biology". </P>

Conjugation occurs in protists and involves the transfer of genetic information between organisms