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Thread: The possibility of designer babies...?

  1. #1 The possibility of designer babies...? 
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    Hello biologists!

    I'm doing some research at the moment, and I'm hoping to get some scientifically accurate information (or opinion). Speaking at a biological level, what has been done to further advances in designer babies? I'm speaking about being able to pick and choose specific genetic traits, whether physical or mental.

    I'm aware of cellular structure, how DNA works, things like recombinant DNA, etc. - so in terms of actual method, is there anything new or interesting happening? Are such things becoming more possible as we learn about DNA? Or is it all just sci-fi?

    Thanks
    Rup


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    Those are polygenetic traits, I'm guessing it would take a lot more studying to determine what versions of genes you'd need to make a "smart" child. Also, is there a way to test an individual sperm or ova for specific genes without ripping it apart? The only possible method I see here would be to unify a sperm and ova, and isolate the DNA from a cell that's very early in development. You'd then have to successfully pcr out the genes of interest, analyze them with a DNA microarray to see if they contain the genes associated with the traits you want. Then you would either discard, or implant the embryo. The expense involved with this would be phenomenal, and the hit/miss strategy would make it even more so. Also, the ethics(not to mention politics) involved would surely keep this from ever happening. I can't imagine we would have any other way, at the moment, to do anything like this otherwise.


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    Thanks Misha. That's a very helpful post

    Also, is there a way to test an individual sperm or ova for specific genes without ripping it apart?
    Interesting question. On a similar note, would it be possible to 'build' an individual sperm to have the required genes?

    Of course the cost would be prohibitive, and the ethics even more so - this is all just speculation on my part!
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  5. #4  
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    Quote Originally Posted by RupertM
    Interesting question. On a similar note, would it be possible to 'build' an individual sperm to have the required genes?
    In principle, yes. We might do it by synthesising a set of artificial chromosomes, removing the contents of a sperm cell's nucleus and replacing it with the new chromosomes along with a cocktail of enzymes and other proteins suspended in nucleoplasm.

    Right now, we can only synthesize relatively small stretches of DNA from scratch, and stitching genes together is a bit of a hit and miss process. So a full set of synthetic chromosomes is currently beyond our capability. I'm also not sure if we've ever tried to remove the contents of a cell nucleus, though we have done nuclear transfer. So again, that's probably a significant barrier to overcome.

    Easier would be to insert desirable genes into existing chromosomes using gene therapy. This raises the risk of triggering tumorigenesis, plus it isn't necessarily guaranteed that the inserted genes will be expressed appropriately, particularly if they recessive relative to alleles already present in the sperm cell's genome.
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    Quote Originally Posted by TheBiologista
    Easier would be to insert desirable genes into existing chromosomes using gene therapy. This raises the risk of triggering tumorigenesis, plus it isn't necessarily guaranteed that the inserted genes will be expressed appropriately, particularly if they recessive relative to alleles already present in the sperm cell's genome.
    That's what I was thinking. How well can we target gene insertion using viral vectors? I didn't think the risks of randomly interrupting genes with an insertion would be a viable option. Also, even though most of the genome is non-coding, that leaves the question of, as you mentioned, effective expression open since there is a lot more going on than simply having the gene in the genome.
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    How well can we target gene insertion using viral vectors?
    not at all, we have no control over where the it is inserted whatsoever, its totally random haha! By the way, just because most of the genome is non coding for proteins does not mean it is without function...
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    Quote Originally Posted by mishaS
    Quote Originally Posted by TheBiologista
    Easier would be to insert desirable genes into existing chromosomes using gene therapy. This raises the risk of triggering tumorigenesis, plus it isn't necessarily guaranteed that the inserted genes will be expressed appropriately, particularly if they recessive relative to alleles already present in the sperm cell's genome.
    That's what I was thinking. How well can we target gene insertion using viral vectors? I didn't think the risks of randomly interrupting genes with an insertion would be a viable option. Also, even though most of the genome is non-coding, that leaves the question of, as you mentioned, effective expression open since there is a lot more going on than simply having the gene in the genome.
    That depends on what virus we use. Some of them have specific integration sites, though these tend to be viruses with lower integration frequencies, like AAV.

    Quote Originally Posted by Mark Ian
    How well can we target gene insertion using viral vectors?
    not at all, we have no control over where the it is inserted whatsoever, its totally random haha! By the way, just because most of the genome is non coding for proteins does not mean it is without function...
    True, but location and the local tertiary structure does influence how a gene is expressed.
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    edit*
    bah, completely forgot about using homologous recombination. That pretty much negates everything I've posted as it makes very specific gene replacement possible.

    Quote Originally Posted by Mark Ian
    By the way, just because most of the genome is non coding for proteins does not mean it is without function...
    I realize this, and that's why I asked about gene expression effects, since these regions are often regulatory whether they're involved in transcription factor binding, or play any number of other regulatory roles. Further, if we're talking about something that is inserted into heterochromatin, or simply in places that are not regularly exposed to to transcription factors, the gene could very likely simply be silenced. Likewise, if the gene is inserted into a part of the genome only active during development, and silenced afterward, and is thus expressed inappropriately during development, the effects would be quite unpredictable, and very likely detrimental.

    That's also ignoring cell specific controls, which I can't even see being possible without flat out gene replacement. I can't imagine inserting a more sensitive receptor gene, or regulatory gene, in any place, but the correct place, allowing retention of that specific gene being expressed only in the specific cells it is supposed to be expressed in. And even if we could pull this off, we would then have to be able to make a version of said gene(s) that would only up/down regulate only so far to get the desired effect which I imagine is a lot more involved then simply controlling the elevation/inhibition of expression of that specific gene, involving all of the associated regulatory genes.

    I'm still an undergrad, so I'm not an expert, I can only think of a great deal of plausible problems that would face you at every turn if you're trying to use gene therapy during development to induce very specific developmental effects. Targeted gene therapy after development seems to be a much more realistic approach for dealing with pathological conditions.
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    Thanks to everyone who added to this thread. Very useful stuff.
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