Wouldn’t a more limited form of iterated embryo selection still be possible with the oocytes alone? You’d still have to fertilize the eggs with sperm from the current generation, but the eggs could be derived from a selected female embryo, then you do it again, sperm from the current generation, but eggs from second-generation selected female embryos, etc.
This is an interesting idea. I suspect that this type of selection would asymptotically approach twice the per-generation gain of simple embryo selection. So useful but not really transformative.
Are sperm necessary at all? Eggs have also gone through meiosis, so they’re haploid just like a sperm nucleus. Can you just implant the nucleus from a selected embryo’s egg into another selected egg and then add the “you’ve been fertilized” chemical signal? I’m not sure how complex that process is.
If that’s too hard, what about surgically swapping in the nucleus from an egg cell produced from a selected embryo into a healthy sperm cell? Would the sperm function for long enough to fertilize an egg?
Of course, we can only produce females this way, but that could still be transformative (unless you can make oocytes from male cells to get a haploid nucleus? They do have one X chromosome, so they should have the required genes.)
This is an interesting idea. Nuclear transfer has been used in cloning before, but it is not particularly reliable. That being said, perhaps future research could improve the success rate (and more importantly the ease of doing so).
At the end of the day, the entire iterated embryo selection process is about generating a complete DNA sequence that scores better on our tests. I left out whole genome synthesis from the original post because from the brief reading I did on the topic it seemed prohibitively expensive. But that could change in the future, as the cost per base pair has been declining exponentially for some time now. The most notable recent use of whole-genome sequencing was to create the mRNA in the Pfizer-BioNTech and Moderna vaccines.
Wouldn’t a more limited form of iterated embryo selection still be possible with the oocytes alone? You’d still have to fertilize the eggs with sperm from the current generation, but the eggs could be derived from a selected female embryo, then you do it again, sperm from the current generation, but eggs from second-generation selected female embryos, etc.
This is an interesting idea. I suspect that this type of selection would asymptotically approach twice the per-generation gain of simple embryo selection. So useful but not really transformative.
Are sperm necessary at all? Eggs have also gone through meiosis, so they’re haploid just like a sperm nucleus. Can you just implant the nucleus from a selected embryo’s egg into another selected egg and then add the “you’ve been fertilized” chemical signal? I’m not sure how complex that process is.
If that’s too hard, what about surgically swapping in the nucleus from an egg cell produced from a selected embryo into a healthy sperm cell? Would the sperm function for long enough to fertilize an egg?
Of course, we can only produce females this way, but that could still be transformative (unless you can make oocytes from male cells to get a haploid nucleus? They do have one X chromosome, so they should have the required genes.)
This is an interesting idea. Nuclear transfer has been used in cloning before, but it is not particularly reliable. That being said, perhaps future research could improve the success rate (and more importantly the ease of doing so).
At the end of the day, the entire iterated embryo selection process is about generating a complete DNA sequence that scores better on our tests. I left out whole genome synthesis from the original post because from the brief reading I did on the topic it seemed prohibitively expensive. But that could change in the future, as the cost per base pair has been declining exponentially for some time now. The most notable recent use of whole-genome sequencing was to create the mRNA in the Pfizer-BioNTech and Moderna vaccines.
Maybe I’ll write a future post about this topic.