General Discussion
In reply to the discussion: Neil deGrasse Tyson Tells GMO Critics to "Chill Out" [View all]mike_c
(36,279 posts)The most spectacular example of all is one that most people overlook-- all eukaryotes (which includes all multicellular organisms on Earth) carry prokaryote genes in their mitochondria. Likewise all plants carry prokaryote genes in their plasmids (as well as their mitochondrial DNA). That lateral transfer created the entire eukaryote branch of life, to which all plants, animals, fungi, and protists belong. It is likely that at least some nuclear DNA arrived this way, too. Within individual cells, lateral transfer occurs between nuclear DNA and mitochodrial and plasmid DNA, too.
Lateral transfer also occurs between at least some plant lineages, and some nudibranchs incorporate plasmids (and their DNA) from photosynthetic algae into their tissues, where they happily photosynthesize for them.
It is also common among eukaryote protists who are phagotrophic, i.e. engulf other cells whole.
However, as I mentioned in other responses, it is not common among animals for reasons that have to do with the evolution of mechanisms for maximizing reproductive fitness, and as far as I'm aware lateral transfer of nuclear DNA is not the norm in multicellular eukaryotes. The barriers to lateral gene transfer in animals (and most plants) are almost entirely reproductive, not genetic. That is one reason that genetic engineering works so well. The evolution of reproductive isolation apparently has little to do with genetic difficulties, but probably has much to do with insuring individual reproductive fitness by focusing on gamete transfer (vertical gene transmission) which individuals can control. The prevalence of lateral transfer in single celled asexual reproducers suggests that the two mechanisms are equivalent, complementary methods of genetic recombination between organisms, best suited for different life forms and lifestyles.
However, as I said, genetic engineering is largely about circumventing reproductive isolation, and once that is accomplished lateral gene transfer is relatively easy and effective in multicellular organisms because there simply are not strong genetic barriers to lateral transfers. Plants are perfectly happy with bacterial or animal DNA in their genomes, as long as they don't have to hybridize successfully to get it there.
on edit-- Oh, and just to really shake things up, think about traumatic insemination in bed bugs-- it's both (within species) lateral AND vertical gene transfer simultaneously when a male bedbug pierces the abdomen of another male, deposits his sperm inside the cavity, and the sperm migrate to the other male's seminal vesicles where they wait for him to do the same thing to a female bedbug. Then the second male inseminates the female with the first males's gametes.
Just did a quick search and found some more examples. Take a look at the Wikipedia page: http://en.wikipedia.org/wiki/Horizontal_gene_transfer . I'd forgotten about Wolbachia in insects, for example.