lecture 7 - ONT Flashcards
(11 cards)
What principle does ONT sequencing use?
ONT does not use DNA polymerases.
ONT is based on a completely different principle than Illumina technologies.
What type of protein does ONT utilize for sequencing?
Pore-hemolysin.
These barrel-shaped proteins regulate which molecules can enter or leave the cell.
What is the inner diameter of pore-hemolysin?
1 nm.
This size allows a single strand of DNA to pass through.
How are ONT flow cells controlled?
By an electronic chip under an artificial membrane with protein nanopores.
The electronic chip regulates the flow of DNA through these nanopores.
What happens when a voltage is applied across the ONT membrane?
Negatively charged DNA molecules are attracted through the nanopores, obstructing the current.
This obstruction is used to gather sequencing data.
What causes current variations in ONT sequencing?
The different shapes and sizes of the four DNA bases.
These variations are essential for generating raw data in ONT sequencing.
What converts current variation traces into a DNA sequence in ONT?
A base-calling algorithm.
This algorithm is crucial for interpreting the raw data collected during sequencing.
What is a disadvantage of ONT sequencing compared to other technologies?
Lower accuracy than some other technologies.
What is a significant advantage of ONT reads?
Reads can reach several millions of base pairs.
This reduces the number of pieces needed to assemble sequencing data into a genome.
How does the size of ONT instruments compare to other sequencers?
ONT instruments are between the size of a mobile phone and a microwave.
In contrast, Illumina and PacBio sequencers are similar to large fridge-freezer units.
Where has the smallest ONT sequencer been used?
In low-income countries, during the Ebola pandemic, in Antarctica, and on the International Space Station.
