Last week, I wrote about the potential of personalized medicine, and I briefly mentioned the role of genetic sequencing and the Human Genome Project (HGP) in making personalized medicine possible. This week, I want to delve a little deeper into what exactly goes into sequencing a genome. The HGP, which took 13 years to complete, was performed using a process known as Sanger sequencing. Sanger sequencing, invented in 1977 by Fred Sanger, is a laborious and costly process of sequencing. In the HGP, relatively tiny fragments of the human genome were sequenced multiple times and aligned together, piece by piece,…
Comments closedMonth: June 2020
The last few weeks, I have written about the complex molecular immunity mechanism of CRISPR and how we can harness it to precisely edit genes in a gamut of cells. But the ability of CRISPR to treat genetic disorders, predispositions, and susceptibilities relies on our understanding of the genetic basis of disease. Since the completion of the Human Genome Project (HGP) in 2003, which sought to sequence the entire human genome, scientists have made great strides in connecting diseases and disorders with their genetic backgrounds. In the meantime, the invention of Next Generation Sequencing (NGS) in 2006 has drastically reduced…
Comments closed
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 Comment
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…
Comments closed