Pseudogene function: regulation of gene expression

Discussion in 'Science' started by Gup20, Jul 13, 2005.

  1. Gup20

    Gup20
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    Full Article here

    Article Summery:
    The discovery of a functional nitric oxide synthase (NOS) pseudogene compels us to understand pseudogenes in a new light. It confirms earlier clues suggesting that seemingly nonfunctional pseudogenes can regulate the expression of paralogous genes by producing antisense RNA. Moreover, only a partial sequence complementarity between sense and antisense segments of the gene and pseudogene is compatible with this function. This confutes the common evolutionary belief that major differences in sequence between paralogous genes and pseudogenes imply that the latter is necessarily a nonfunctional gene copy in a state of mutational drift. A second pseudogene may regulate the NOS gene by producing a truncated protein that can bind with the normal protein to produce an inactive heterodimer. Finally, the world of noncoding RNA, whether sense or antisense, offers further large-scale possibilities for undiscovered pseudogene function.

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  2. UTEOTW

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    Wow! You find an example of a pseudogene that has a function and you think you have overturned the whole logic of the shared pseudogenes as a marker of shared descent.

    Let's take a look at why this logic is wrong.

    This discussion always comes back to vitamin C. Here we have a case where four different genes code for different enzymes to make a single product. We know that in all primates that one particular gene of the group is broken and in the same manner. We also can compare the accumulated mutations since the disabling one for phylogeny and compare this tree with others from independent means. It is the classic case of a psuedogene and is well documented. Does my one example trump yours?

    But let's move on. There is a second reason why remnant function in a pseudogene is not surprising. The human genome is very complex. Many sections of DNA code for more than one protein. The are complex interaction with RNA produced from some sections of DNA that regulate other functions. A mutation may knock out a DNA section that makes part of a protein, turning it into a psuedogene, without altering some of the other functions that bits of the DNA may perform.

    There is another logical reason that I can come up with. Probably the most important source of new genetic variety is the duplication and subsequent mutation of sections of DNA. These old genes can become something new. In a not dissimilar manner, why is it hard to imagine that a pseudogene through further mutation might become useful in some new role?

    Another problem for you is that there have been studies where large sections of DNA believed to be noncoding have been removed with no ill effects. There must not have been any improtant regulatory fnctions in those sections.

    Finally, you ignore a very important way to identify the junk. DNA is divided into three "letter" codons that code for amino acids and starts and stops and so on. Mutation does not equally affect all three positions of each codon, however. Changes to the first two positions will usually result in significant change to the resulting protein. However, changes to the third position will generally result in either the same amino acid or a very similar one. These changes are often reffered to as silent. In coding DNA, the changes tend to be more preserved in the third position becuase other changes will normally destroy the function of the protein and will be selected against. In noncoding DNA, mutations can happen to all three positions and should not favor the silent mutations only.

    So you have a much higher mountain to climb to disprove the implications of pseudogenes than finding use for one or a couple.
     
  3. Gup20

    Gup20
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    Evolutionists have touted for years that there is this large store of "junk" in our DNA that it champions as evidence leftover from our mutational evolution. Daily, more and more usefulness is being discovered in what used to be considered junk DNA. Like the appendix, once thought a vestigial leftover from evolution, this only serves to diminish to so-called evidence for evolution. As this pool of "evidence" shrinks, I will have been glad to have stuck with my creationist views that line up with scripture. Eventually science will have no choice but to abandon the concept of vestigial organs and junk DNA. Because my views are not weighed down by evolutionary dogma, I am free to watch science get closer and closer to the truth revealed in scripture, and farther and farther away from evolution. This will be yet another item in a long list of abandon "evidences" for evolution. It's interesting to see the multitude of evidences which have been abandon, yet see the faith in evolution remain the same as it has ever been. Truly, evolution is more faith than fact.
     
  4. UTEOTW

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    "Evolutionists have touted for years that there is this large store of "junk" in our DNA that it champions as evidence leftover from our mutational evolution. Daily, more and more usefulness is being discovered in what used to be considered junk DNA."

    You did nothing to dispel the reasons I gave above for identifying some DNA as genuine junk just as you have no answer for the implications of this junk.

    Sorry to spam one of my posts from another topic, but it seems relevant.

     

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