Reading 22 Flashcards
What is the Sanger method of DNA sequencing?
-method of DNA sequencing based on the selective incorporation of chain-terminating dideoxyribonucleotides by DNA polymerase during in vitro DNA replication
-developed by Fredrick Sanger
How long did it the take the Human Genome Project consortium to deliver the ‘final draft’ of the human genome reference sequence?
-over a decade
In contrast, how long does it take to sequence a single human genome using next-generation platforms (from the Behjati and Tarpey review)?
-a single day
What types of genetic variation does the “spectrum of DNA variation within a human genome” consist of?
-small base changes, insertions/ deletions, large genomic deletions of entire exons, inversions, translocation
Finish the sentence: “Traditional Sanger sequencing is limited to the discovery of _______________________ and small _________________ and __________________.”?
-substitution, small insertions, deletions
Since Sanger sequencing is so limited in the types of genetic variation that can be detected (base substitutions, small insertions and deletions), what other methods were traditionally used for detection of larger genetic variants, such as larger genomic deletions and rearrangements such as inversions and translocations?
-fluorescence in situ hybridization (FISH) for conventional karyotyping
-comparative genomic hybridization (CGH) microarrays to detect submicroscopic chromosomal copy number changes like microdeletions
True of False: Capillary sequencing methods (i.e., Sanger sequencing) relies on the existing knowledge of the gene or locus under investigation?
-True
What is “mosaicism”?
-mosaic mutations are acquired as postfertilization event and consequently they present at variable frequency within the cells and tissues of an individual
Why is capillary sequencing (Sanger sequencing) likely to MISS mosaic mutations?
-they frequently present with a subtlety which falls below the sensitivity of the technology
