It is now possible to detect Huntington’s disease genes. Short oligonucleotides to the rescue. A probe of
small length, around 21 bp. Raising the temperature by a bit will not pry off the probe. A single
mismatch of the probe would result in the probe falling off.
ASO: allele-specific oligonucleotides, they are short enough to allow differential hybridization, but long
enough to ensure locus specificity. Human genome is about 3 * 10 bp long, having 21 exact match ups
in a line would be very rare. Specific probes to specific sequences would allow for tagging of genes.
PCR amplify the fragment, then use ASO. Spot the genetic slush onto a membrane. Then wash away the
membrane to see if hybridization has taken place. This removes the need to run a gel and can be
automated, but requires a prior knowledge of the sequence.
The Cystic Fibrosis gene is extended across 250,000 bp and is organized into 24 exons and encode the
CFTR protein which forms the ion channels of epithelial cells. Most CF (70%) is caused by the deletion of
CTT in exon 10. The primer must be outside of the region looked at, since the primer itself won’t be seen