Shared errors

Over at Pharyngula, PZ Myers has a post which first destroys some creationist misconception, but then, far more interestingly, goes on to interpret a recent peer-reviewed paper on copy number variants, or CNVs. The whole piece is worth reading, but what I think is worth of a little extra attention is the brief point our shared errors.

An architecture does not imply intent or purpose, but they often imply a history. The pattern described — that chimps and humans share some common structural elements in their genomes — is better described as evidence of common ancestry than of well-designed function. An intron, for instance, is a piece of random, usually useless DNA inserted into the middle of the sequence of a gene that must be excised from RNA before it can be used to make a functional protein. It’s a little piece of garbage that must be cleaned up before the gene product can do its job. That a human and chimpanzee gene has identical introns is an example of an architecture, true enough, but it is of a shared error. Some all-knowing god—he seems to be consistently making the same mistake.

Okay, let’s take the recent hoo-hah with Coldplay and Joe Satriani. Basically, Satriani is claiming Coldplay ripped off one of his songs. There is some fairly compelling evidence to this claim, but it is far from airtight. What we have are four of the same chords repeating through parts of the songs, but only three consecutive notes are truly in common. We can potentially call this one a coincidence (especially since this song has been around forever and Satriani is only suing now that after Coldplay has won a slew of awards. Essentially, we see two instances of people creating similar things.

Now let’s consider someone learning the Satriani song. I don’t feel like finding the actual chord progressions, so let’s just say it goes A, B, C, D. The person begins to learn things, but is apparently a horrible musician and substitutes an F# for the C. Okay, fine. So we have a version of the song out there which is now A, B, F#, D. Now let’s say this person has a friend who wants to rip the song off. But instead of listening to the original Satriani version, he listens to the mutated version with the F#. Now we have some evidence of a copycat. It isn’t very strong evidence because there is just one error. In both instances, we have just four chords. But let’s say another error is made further along in the song. A chord in the bridge is misinterpreted by the original person learning the song. And, naturally, the copycat makes the same error. As we go deeper and deeper into errors, we begin to get better and better evidence of a common origin – the friend was learning from the interpreted version of the song, not the Satriani version, because it is unlikely he would make, say, 5 of the same errors as his friend. The chance for coincidence shrinks while the odds of identifying the correct source rise.

The way this is like CNVs is that we are seeing common errors being made again and again – and these errors are present in both human and chimp genomes. Of course, it should be noted that it isn’t entirely clear if these errors were directly inherited from a common ancestor or if it was the hotspot for ‘making’ errors is what was inherited, but at any rate, it is evidence for our common ancestory with the other apes. There are far too many common errors being made to simply file this under ‘God did it’. The evidence says that is – still and again – superfluous.

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8 comments on “Shared errors

  1. Okay, let’s take the recent hoo-hah with Coldplay and Joe Satriani. Basically, Satriani is claiming Coldplay ripped off one of his songs. There is some fairly compelling evidence to this claim, but it is far from airtight. What we have are four of the same chords repeating through parts of the songs, but only three consecutive notes are truly in common. We can potentially call this one a coincidence (especially since this song has been around forever and Satriani is only suing now that after Coldplay has won a slew of awards. Essentially, we see two instances of people creating similar things.

    Now let’s consider someone learning the Satriani song. I don’t feel like finding the actual chord progressions, so let’s just say it goes A, B, C, D. The person begins to learn things, but is apparently a horrible musician and substitutes an F# for the C. Okay, fine. So we have a version of the song out there which is now A, B, F#, D. Now let’s say this person has a friend who wants to rip the song off. But instead of listening to the original Satriani version, he listens to the mutated version with the F#. Now we have some evidence of a copycat. It isn’t very strong evidence because there is just one error. In both instances, we have just four chords. But let’s say another error is made further along in the song. A chord in the bridge is misinterpreted by the original person learning the song. And, naturally, the copycat makes the same error. As we go deeper and deeper into errors, we begin to get better and better evidence of a common origin – the friend was learning from the interpreted version of the song, not the Satriani version, because it is unlikely he would make, say, 5 of the same errors as his friend. The chance for coincidence shrinks while the odds of identifying the correct source rise.

    Actually you articulate here an excellent argument for intelligent design by agreeing we can identify intention through the statistical probability that a pattern has been created by intelligence. Indeed, if we couldn’t do this, no artist or musician could ever make a case that they were copied.

  2. It’s up to you if you want to claim God makes errors and deceives us into seeing overwhelming evidence for evolution.

    I am not sure how introns come to be seen as errors, but that is irrelevant to the point; as you note, if we see information organized in a certain way that can’t be attributed to chance, intelligence is a reasonable inference.

  3. This is about copy number variations. They imply errors, or mutations, by definition.

    The fact that an intron – nothing more than garbage – is found in a particular location of a sequence in two separate species indicates that a mistake has been maintained (by chance) from one common ancestor, or at least because both species share a common ancestor and thus have a predisposition to CNVs in a particular region.

  4. This is about copy number variations. They imply errors, or mutations, by definition.
    The fact that an intron – nothing more than garbage – is found in a particular location of a sequence in two separate species indicates that a mistake has been maintained (by chance) from one common ancestor, or at least because both species share a common ancestor and thus have a predisposition to CNVs in a particular region.

    One of the great failures of evolutionary theory has been the regular classification of various DNA regions as’ junk’. Here for example is a recent determination of an important function of an intron in nerve-cell channel production.

    So claiming that the intron apes and humans share commonly are ‘garbage’ is in a sense a ‘garbage of the gaps’ argument – you don’t know the function of the regions, so you call them garbage, despite the regular finding of function for supposed ‘junk DNA’.
    Interestingly, that in and of itself is a science stopper, because if you assume it has no function, you don’t investigate and find what its function might be. So much for evolutionary thinking reducing ignorance.

    Also, evolution fails to explain why it is such regions are highly conserved over millions of years of genetic modification; if evolution is advancing by way of regular incidental mutation, why then are there so many regions which seem impervious to it, despite the fact they aren’t apparently necessary to the function of the organism?

  5. “Junk” means non-coding.

    You’re missing the point of the argument. Introns (and other regions) which are not subject to natural selection and are therefore more free to mutate than other areas are good evidence for our common ancestory with the other apes because errors (mutations, or alleles) in non-coding regions are unlikely to occur as separate events, especially in the number that we see.

  6. “Junk” means non-coding.

    Well, considering that certain regions of non-coding DNA have been shown to be essential, it seems like an odd definition of junk.

    You’re missing the point of the argument. Introns (and other regions) which are not subject to natural selection and are therefore more free to mutate than other areas are good evidence for our common ancestory with the other apes because errors (mutations, or alleles) in non-coding regions are unlikely to occur as separate events, especially in the number that we see.

    And yet the point of comparing introns is that they haven’t mutated at all over the eons.
    Interestingly, if the above argument is true (introns are useful fodder for future function through mutation) then it would seem one more reason why introns aren’t junk at all, and thus not a basis to argue their existence somehow disparages the notion of an intelligent designer.

  7. Well, considering that certain regions of non-coding DNA have been shown to be essential, it seems like an odd definition of junk.

    If you finish that bio degree, you’ll get to debate this with your professors.

    And yet the point of comparing introns is that they haven’t mutated at all over the eons.

    Honestly? Where have you been? This discussion is based upon CNVs – which do not only include introns, incidentally. That’s copy number variants. Deletions and duplications are seen repeated in closely related organisms. That is, the same errors are being made, in several different regions, and being inherited and spread as species originate.

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