Evolution is a Fact #5 - Vitamin C

by cofty 31 Replies latest watchtower beliefs

  • cofty

    Part 1 - Protein Functional Redundancy
    Part 2 - DNA Functional Redundancy
    Part 3 - ERVs
    Part 4 - Smelly Genes

    In part 4 we saw that roughly half of the 800 genes in the human genome that code for olfactory receptors are broken remnants of our evolutionary history. They were vital to our distant ancestors but in humans, as in our primate cousins they have been allowed to fall into disuse as our eyes became more important to our survival than our nose. The damaging mutations in these genes beautifully confirm the evolutionary history that is known from multiple other lines of evidence.

    This post is going to look at another excellent example of a pseudogene - one of around 19,000 the human genome.

    Vitamin C - ascorbic acid - is essential to life. Without it we are unable to repair connective tissues resulting in the disease known as scurvy that claimed the lives of as many as 2 million sailors from the 16th to the 18th century. It was discovered that citrus fruits provided an almost miraculous cure for the disease - men who were very sick fully recovered within less than a fortnight of receiving fruit in their diet - but the chemical responsible was not isolated until the 1920s.

    Not until far more recently was it discovered that humans possess the genetic machinery to produce their own vitamin C.

    The majority of animals produce vitamin C in a multi-stage process - this is why you don't need to buy dog food enriched with vitamin C. Humans have the genes for all but the final stage. Actually we do have the final gene - it's known as GULO - but it's broken.

    The significant thing for evolution is the fact that the same gene is broken in all our closest relatives.

    The diagram below is a cladogram showing evolutionary relationships based on multiple independent sources of evidence. The clades shaded in red are all unable to produce vitamin C due to the same mutation at the same place in their genomes.

    There is no rational explanation for this fact other than the conclusion that humans evolved from a common ancestor of other primates.

  • breakfast of champions
    breakfast of champions

    This is really interesting. . . .

    Next time my wife tries to force vitamin C pills on me, I'll tell her Jehovah's to blame for breaking my GLUO.

  • DJS

    Thanks Cofty,

    But you had me at hello. Well actually you had me at Hello (Part 1), How are ya (Part 2) and especially How YOU doin' (Part 3).

    Now will you have your lawyer speak to the judge about maybe ending that restraining order? I mean seriously, how often can I make it to the other side of the damned Atlantic.

  • cofty
    Your pint is still waiting for you DJS - proper beer!
  • LoveUniHateExams

    Cracking OP!

    Lemurs are prosimians - i.e. they're primitive primates. It seems that at least some of the taxa highlighted in pink (and thus not being able to synthesize vit C) are more derived forms.

    Just out of interest, are paleoanthropologists or palaeontologists any the wiser as to why the GULO gene is 'broken'?

    Could it be that as fruit features heavily in the diets of different primates, the taxa in pink can get all necessary vitamin C from fruit?

  • cofty
    Could it be that as fruit features heavily in the diets of different primates, the taxa in pink can get all necessary vitamin C from fruit - LUHE

    Yes that is the logical assumption. The ancestor with the mutation suffered no disadvantage as they were getting plenty vitamin C from a fruit diet.

    There are also a few ideas about a possible advantage of the mutation but I have never heard a convincing example

  • cofty

    So this fella can produce his own vitamin C...

    but this little one can't...

  • Clambake

    How many degrees do you have?

    How many papers do you have published?

    Has any of what you are spewing been peer reviewed?

    If you want to a have a discussion about the implications of how the theory of evolution changed how you feel about religion or the such, go ahead. That is the reason this forum exists.

    The problem I have is you are pretending you are an actual scientist while what you really are is just another windbag militant atheist proselytizing. Proselytizing in any form is just annoying on this board.

    Go away.

  • Giordano

    Clambake you need to go....on the internet and look stuff up.

    Since Cofty's information is verifiable I suggest you first do that. If you find something that differs post it otherwise please note that you are annoying this discussion.

  • OneEyedJoe

    Ease off, clambake. This is all really basic stuff regarding evolution that Cofty is taking time out of his day to organize and post in a thoughtful way for those that are interested. He makes no claim to be furthering evolutionary research and he makes no claim to have special qualifications aside from having done his own research on the matter.

    Has any of what you are spewing been peer reviewed?

    Yes, all of what he's been posting has been, because it's all very well understood and accepted fact in the field of evolutionary biology.

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