Question

There are four aneuploidy conditions involving the sex chromosomes that have been quite well studied in humans, XXX, XO, XXY and XYY.

1C. Could CRISPR biotechnology treat one of these diseases? Why or Why not? Your answer needs to explain how CRISPR works in making your argument.

Answer 1

CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats is a system observed in bacterial systems that helps them to eliminate the invading viral particles. It is sort of like an immune system for the bacteria.

This system has been utilized by scientists to develop the CRISPR/Cas9 system. This system can be used to selectively engineer the target genes.

For the system to work, two plasmids are delivered inside the host cell. The first plasmid encodes for the enzyme Cas9 which is a nuclease and basically works by chopping the DNA off. To ensure that this chopping is done at the desired place, the second plasmid is provided with sgRNA. sgRNA is a small sequence of RNA that is desired complementary to the target sequence. This RNA is recognized by the Cas9 enzyme. Binding of sgRNA to Cas9 targets Cas9 to the specific site on the DNA. Thus, Cas9 can now selectively cut at the target site thereby causing the deletion of a specific segment of DNA or gene.

This technique can be exploited to silence an entire chromosome. This can be done by providing a repertoire of sgRNAs that go and bind to genes on the desired chromosome thereby leading the suppression of it. This can be used to target and specifically delete a single copy of a chromosome. However, it cannot be used to bring in a new chromosome from scratch when one is missing.

Thus, it can be used for an extra X from XXX and XXY. It can also be used to delete an extra Y from XYY. But it cannot be used to treat XO aneuploidy.