Human evolution News

Genes unique to humans?

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Well, there would have to be some, wouldn’t there? Otherwise, genomics would be hardly anything like it’s cracked up to be.*

From the Atlantic:

These genes might have contributed to the distinctive traits that make us human, but ironically, they are also very hard to study and often ignored. Many are missing from the reference human genome, which was supposedly “completed” in 2003.

One such unique human gene is HYDIN2. It first appeared around 3.1 million years ago, as a duplicate of an existing gene called HYDIN. During the duplication process, “the head got chopped off and the tail got chopped off,” explains Max Dougherty from the University of Washington. It was as if someone had transcribed a book but neglected the prologue and epilogue. That should have been a fatal mistake since the prologues of genes contain sequences called promoters, which switch them on or off. The new gene should have been dead on arrival—a book that couldn’t be opened.

Instead, as luck would have it, it fused with a copy of another gene, which gave it a new lease on life.

Every human being has this new gene.

The second of these, SRGAP2C, is especially interesting. It emerged around 2.4 million years ago, at the time in our evolution when the human brain was becoming distinctively bigger. And Franck Polleux from the Scripps Research Institute showed that SRGAP2C controls the growth and movement of neurons, leading to a thicker set of connections between these cells.More.

They tried testing one of these unique genes on mice, who developed deep brain folds like humans, but weren’t any smarter in consequence.

More surprises lurk, one guesses.

Note: No mo news bloggo till tonight, due to O’Leary for News’s other alternate night job.

*One mentions this because campus dumbdown machines are in high gear worldwide, producing grads so dumb that they can’t see that. Oh well, time to wipe the coffee stains off the tables, and then off to pay the next installment off the student loan, while living on tips … it’s all someone else’s fault anyway!

See also: What we know about human evolution

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10 Replies to “Genes unique to humans?

  1. 1
    ppolish says:

    ““The fact that these human-specific genes are still being discovered, years after the Human Genome Project, is pretty frickin’ amazing to me,” says Eichler.”

    “Fricking amazing” is the step that comes after “surprised by”. Evo Bio making progress:)

  2. 2
    Zachriel says:

    One such unique human gene is HYDIN2.

    A new gene which is a simple truncation of an existing gene.

  3. 3
    ppolish says:

    “simple truncation” Zachriel? Article sure doesn’t frame it as “simple”. Certainly would not be predicted to happen.

  4. 4
    ppolish says:

    The micro molecular machinery required for the truncation process itself is mind boggling complex. “Simple truncation” please. Zachriel, you are a babe in the woods fcol.

  5. 5
    bornagain says:

    semi related:

    The Information Enigma – Eric Metaxas – October 21, 2015
    Excerpt: in experiments Axe conducted at Cambridge, he found that for a DNA sequence generating a short protein just 150 amino acids in length, for every 1 workable arrangement of amino acids, there are 10 to the 77th possible unworkable amino acid arrangements. Using the bicycle lock analogy, that’s a lock with 77 dials containing 10 digits.
    Thus, as the film states, it is overwhelmingly unlikely that a random mutational search would produce even one new functional protein in the entire history of life on earth.
    http://www.breakpoint.org/bpco.....y/13/28340

    Information Enigma – video
    https://www.youtube.com/watch?v=aA-FcnLsF1g

  6. 6
    Zachriel says:

    ppolish: “simple truncation” Zachriel? Article sure doesn’t frame it as “simple”.

    Duplication, insertions and deletions are common natural occurrences. They even occur within your own cells during replication.

  7. 7
    Virgil Cain says:

    Duplication, insertions and deletions are common natural occurrences.

    Natural in what way? Artifacts are natural in that they exist in nature.

    They even occur within your own cells during replication.

    the question is whether or not they are accidents or designed.

  8. 8
    vjtorley says:

    Hi News,

    I would urge caution regarding the number of genes which are unique to human beings. Last year, Dr. Cornelius Hunter published a post over at Darwin’s God in which he cited A 2011 paper out of China and Canada that found “60 protein-coding genes in humans that are not in the chimp. And that was an extremely conservative estimate.”

  9. 9
    vjtorley says:

    (Continued)

    Sounds impressive. But then a computer scientist named Glenn Williamson posted a reply:

    “So how many ORFan genes are actually in humans???”

    Depends what you call an ORFan gene. I looked at the paper that Cornelius cites as having 60 de novo protein coding genes.

    Now, granted that I only looked at the very first one (“ZNF843”), it was quite easy to find the corresponding DNA on the chimpanzee chromosome, with approximately 98.5% identity.

    So whether it is protein-coding in humans and non-coding in everything else doesn’t really concern me. What concerns me is whether it has an evolutionary history: clearly this one does.

    Like I said, I’ve only done one. I’d happily take bets on the majority of these de novo genes having an evolutionary history (chimpanzee > 95% and/or gorilla > 90%).

    Any takers?

    I think we need to wait until we have more data.

  10. 10
    mahuna says:

    ” It first appeared around 3.1 million years ago”

    I’m guessing, since it is not stated in the text, that all of the guesses at when a certain gene first appeared is based on one of the accepted rates for random mutations. And in this case, with a unique human gene, the question becomes “mutation from WHAT?”

    If the gene in question was installed directly as part of a new design 1 million years ago, then all attempts to estimate age using a rule of thumb for fixing random mutations are irrelevant. At least until we finally discover The Missing Link and recover its DNA.

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