In November of 2018, Jiankui He, a Chinese biophysicist, announced to the world that he had created the first ever CRISPR-edited human babies. The experiment resulted in twin girls, Lulu and Nana, who developed from embryos with a modified version of the CCR5 gene meant to increase resistance to HIV. The experiment was riddled with breaches and blunders, and it quickly became an international scandal. At the end of 2019, He was sentenced to three years in prison for “illegal medical practices.” All of the flaws in He’s experiment highlight just how far we still have to go before embryonic…
1 CommentCategory: Genetic Engineering
CRISPR-Cas9 has made genetic engineering easier, faster, and cheaper than ever before. A scientist interested in manipulating a particular gene only needs to search the gene’s sequence for a suitable PAM. Once a PAM is found, the corresponding Cas9 can be ordered or harvested from its bacterial strain (and as I mentioned last week, even if a PAM isn’t found, it is possible to engineer a Cas9 to recognize a new PAM sequence). An appropriate sgRNA (the crRNA:tracrRNA fusion molecule) can be designed by identifying the target sequence 20 nucleotides upstream of the chosen PAM. These sgRNA’s can be engineered…
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If you’ve ever seen the movie Gattaca, then you probably know something about the concept of genetic engineering. However fictionalized that movie may have seemed (my favorite part was a full genome sequence printed on one small tube of rolled up paper), it did bring up a lot of interesting ethical questions that are suddenly becoming more and more relevant. Widespread genetic engineering isn’t yet a reality, but it certainly could be within our lifetime. In the last decade, scientists have discovered a way to hijack the CRISPR-Cas9 system in bacteria to make efficient and targeted genetic editing possible. However, as we…
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The last few weeks, we’ve talked a lot about the immune system and how it builds and maintains immunity to viral pathogens, like Covid-19. This week, I’d like to shift a bit to a different form of immunity that doesn’t have anything to do with the coronavirus (I know, a blog post that’s not about Covid-19—shocking) but one that has had major implications in the field of genetic engineering: bacterial immunity to viral infection. I mentioned briefly in my post about viruses that a large subset of viruses infect bacteria, called bacteriophages. Although bacteria are far less complex than humans are, they…
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