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Horizontal gene transfer from moss to ferns

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File:Phaeoceros laevis.jpg
hornwort/Benutzer:Oliver_S

Here. Despite being one of the oldest groups of land plants, the majority of living ferns resulted from a relatively recent diversification following the rise of angiosperms. To exploit fully the new habitats created by angiosperm-dominated ecosystems, ferns had to evolve novel adaptive strategies to cope with the low-light conditions exerted by the angiosperm canopy. Neochrome, an unconventional photoreceptor that allows ferns to “see the light” better, was likely part of the solution. Surprisingly, we discovered that fern neochrome was derived from a bryophyte lineage via horizontal gene transfer (HGT). This finding not only provides the first evidence that a plant-to-plant HGT can have a profound evolutionary impact but also has implications for the evolution of photosensory systems in plants.

Here’s the abstract (paywall):

Ferns are well known for their shade-dwelling habits. Their ability to thrive under low-light conditions has been linked to the evolution of a novel chimeric photoreceptor—neochrome—that fuses red-sensing phytochrome and blue-sensing phototropin modules into a single gene, thereby optimizing phototropic responses. Despite being implicated in facilitating the diversification of modern ferns, the origin of neochrome has remained a mystery. We present evidence for neochrome in hornworts (a bryophyte lineage) and demonstrate that ferns acquired neochrome from hornworts via horizontal gene transfer (HGT). Fern neochromes are nested within hornwort neochromes in our large-scale phylogenetic reconstructions of phototropin and phytochrome gene families. Divergence date estimates further support the HGT hypothesis, with fern and hornwort neochromes diverging 179 Mya, long after the split between the two plant lineages (at least 400 Mya). By analyzing the draft genome of the hornwort Anthoceros punctatus, we also discovered a previously unidentified phototropin gene that likely represents the ancestral lineage of the neochrome phototropin module. Thus, a neochrome originating in hornworts was transferred horizontally to ferns, where it may have played a significant role in the diversification of modern ferns.

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7 Replies to “Horizontal gene transfer from moss to ferns

  1. 1
    Acartia_bogart says:

    Inter-species swapping of genetic material was not envisioned by Darwin but it is now known to be fairly common, especially among plants and bacteria. This just gives natural selection much more material to work with, and not always relying on mutations within a population as the ultimate source of genetic variation. Now we must take the mutation load amongst different species when looking at evolution, allowing for much higher rates of change than we would expect if a species could only draw from its own DNA.

  2. 2
    Piotr says:

    Plants do it, germs do it, even bdelloid rotifers do it. HGT is extremely rare in animals, but it seems that Bdelloidea have acquired up to 10% of their genome from bacteria, fungi, plants and what not.

  3. 3
    JoeCoder says:

    Is there any evidence of HGT (such as viral genes nearby) or is it just assumed when genes are found to be discordant?

  4. 4
    Acartia_bogart says:

    Joe: “Is there any evidence of HGT (such as viral genes nearby) or is it just assumed when genes are found to be discordant?”

    It may only be a myth, but I believe that there have been examples of GMO genes crossing into other plants.

  5. 5
    Acartia_bogart says:

    Joe, it may only be an urban myth, but I believe that there have been examplesof Genetically modified genes crossing to other plants.

  6. 6
    ppolish says:

    Nature is driving, Nature is guiding these advantageous gene transfers. And a new plant pops into existence in another part of the forest apart from the HGT extravaganza. Where are the modern day Darwins to bring Evo Theory into 21st Century. Way overdue FCOL.

  7. 7
    Mapou says:

    What is not explained is the mechanism of HGT between moss and ferns. But, hey, why explain something you know to be true even if it can never be observed? There is no way it could have been designed.

    Evolutionary biology is pseudoscience.

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