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Stasis: Oldest surviving plant genome, gingko biloba, is really big

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ginkgo biloba leaf from Eocene era

From ScienceDaily:

The research was carried out by a team of scientists at BGI, Zheijiang University and the Chinese Academy of Sciences, who tackled and analyzed an exceptionally large genome, totalling more than 10 billion DNA “letters.” Ginkgo is considered a “living fossil,” meaning its form and structure have changed very little in the 270 million years since it first came into existence. Given its longevity as a species and unique position in the evolutionary tree of life, the ginkgo genome will provide an extensive resource for studies concerning plant defenses against insects and pathogens, and research investigating early events in tree evolution and in evolution overall.

The ginkgo genome stretches over more than 10 Gb, which is 80 times larger than the “model plant” Arabidopsis thaliana genome. The tree’s genome is also larger than other plant species known for extremely big genomes, such as maize or orchids.

Professor Yunpeng Zhao, one of the authors from Zhejiang University, explains how this evolutionary placement is of great interest to researchers: “Ginkgo represents one of the five living groups of seed plants, and has no living relatives. Such a genome fills a major phylogenetic gap of land plants, and provides key genetic resources to address evolutionary questions like phylogenetic relationships of gymnosperm lineages, evolution of genome and genes in land plants, innovation of developmental traits, evolution of sex as well as history of demography and distribution, resistance and conservation of ginkgo.”

Researchers are also fascinated by the ginkgo’s resilience under adverse conditions — it is worth noting that ginkgo trees were one of the few living things to survive the blast of the atomic bombing of Hiroshima. This hardiness likely helped the ginkgo survive periods of glaciation in China that killed many other species, and may also promote the longevity of individual trees, some living up to several thousand years, according to reports. The ginkgo is also able to defend itself against a wide range of attackers, employing an arsenal of chemical weapons against insects, bacteria and fungi.

To better understand the ginkgo’s defensive systems, the authors analysed the repertoire of genes present in the genome that are known to play a role in fending off attackers. Paper. (public access) – Rui Guan t al., Draft genome of the living fossil Ginkgo biloba. GigaScience, 2016; 5 (1) DOI: 10.1186/s13742-016-0154-1More.

See also: We can’t understand evolution without understanding stasis and extinction

and

Stasis: Life goes on but evolution does not happen

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One Reply to “Stasis: Oldest surviving plant genome, gingko biloba, is really big

  1. 1
    bornagain77 says:

    Besides long term stasis, this following tidbit, on the loss of diversity in Ginkgo, came to me from a person named Rude on UncommonDescent:

    “At one of the few petrified forests that sports ginkgo wood, I was told by the naturalist that ginkgos are old in the fossil record—they date from the Permian back when trees were first “invented”. She said that there are many species of fossilized Ginkgoaceae, but Ginkgo biloba, is the only living species left.”
    – Rude – Uncommon Descent Blogger

    Here is an interesting piece of related trivia:

    Jurassic insect that mimicked ginkgo leaves discovered – November 28, 2012
    Excerpt: Researchers working in China have discovered an insect that lived 165 million years ago that they believe used its wings to mimic the leaves of an ancient ginkgo tree. The fossil finding, the team writes in their paper published in the Proceedings of the National Academy of Sciences, is one of the few that shows that early insects mimicked non-flowering plants millions of years before doing so with angiosperms.
    http://phys.org/news/2012-11-j.....inkgo.html

    A few more related notes:

    Another Notable Explosion: Has Darwin’s “Abominable Mystery,” the Origin of Flowering Plants, Been Solved? – Casey Luskin – January 2, 2014
    Excerpt: “Darwin famously characterized the rapid rise and early diversification of flowering plants (angiosperms) in the fossil record as an “abominable mystery.”
    (Well) did the researchers identify any specific, adaptive molecular changes that might help to resolve Darwin’s “abominable mystery”? No, they didn’t. Rather, by comparing DNA sequences in angiosperms to other plants, they found “1179 gene lineages (orthogroups) first appeared in angiosperms” and “The new gene lineages in flowering plants may have led to gene functions specific to angiosperms and crucial for their diversification and success.” In other words, a lot of crucial genes for producing flowers in angiosperms don’t seem to have orthologues (i.e., homologous genes) in other types of plants. This was contrary to Darwinian expectations.
    http://www.evolutionnews.org/2.....80681.html

    Flowering Plant Big Bang:
    “Flowering plants today comprise around 400,000 species,“To think that the burst that gave rise to almost all of these plants occurred in less than 5 million years is pretty amazing – especially when you consider that flowering plants as a group have been around for at least 130 million years.”
    Pam Soltis, curator at the Florida Museum of Natural History.

    Tracing the evolution of forest trees – Nov 10, 2014
    Excerpt: There are at least 60,000 identified tree species in the world, “but we know next to nothing about how they got here,” Elizabeth Stacy says. “Trees form the backbone of our forests, and are ecologically and economically important, yet we don’t know much about how speciation happens in trees.”
    http://phys.org/news/2014-11-e.....trees.html

    Thank God for Flowers – Hugh Ross – August 2010
    Excerpt: Paleontologist Kevin Boyce and climate modeler Jung-Eun Lee,,, recently discovered that flowering plants contribute much more than romance and beauty to humanity’s wellbeing. They uncovered evidence suggesting that without flowering plants, human civilization would not even be possible. Boyce and Lee found that a world without angiosperms (flowering plants) would not only be drab and uninspiring but would also be much drier and hotter and lacking in species diversity. The researchers noted that angiosperms transpire water to the atmosphere about four times more efficiently than other species of plants.
    http://www.reasons.org/thank-god-flowers

    as to this comment from the OP: “The ginkgo is also able to defend itself against a wide range of attackers, employing an arsenal of chemical weapons against insects, bacteria and fungi”,,,
    It turns out that plants are far more sophisticated than most people realize, (and far more sophisticated than would be expected on Darwinian presumptions):

    Plants, say the authors, are highly responsive, attuned to gravity, grains of sand, sunlight, starlight, the footfalls of tiny insects and to slow rhythms outside our range. They are subtle, aware, strategic beings whose lives involve an environmental sensitivity very distant from the simple flower and seed factories of popular imagination.
    http://www.uncommondescent.com.....are-smart/

    Plants may be able to ‘hear’ others – June 2012
    Excerpt: Plants are known to have many of the senses we do: they can sense changes in light level, “smell” chemicals in the air and “taste” them in the soil (New Scientist, 26 September 1998, p 24). They even have a sense of touch that detects buffeting from strong winds.,,,
    http://www.newscientist.com/ar.....thers.html

    etc.. etc..

    It is also interesting to note that two fairly renowned plant Geneticists, Wolf-Ekkehard Lönnig and John Sanford, are both fierce critics of Darwinian evolution. Here are links to some of their main papers against Darwinian evolution:

    Wolf-Ekkehard Lönnig
    http://www.weloennig.de/internetlibrary.html

    John Sanford – Genetic Entropy – papers
    http://www.geneticentropy.org/properties

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