Biotechnology

Chapter 9

DNA fingerprinting

Identification based on unique sets of bands in DNA

How is DNA fingerprinting performed?

1. Restriction enzymes

2. Gel electrophoresis

Restriction enzymes

Enzymes used to cut DNA at specific sequences (different people have different cut sites, causing the length of DNA segments to differ from person to person)

Gel electrophoresis

Technique used to separate DNA by size using electricity (negatively charged DNA is pushed away from electrons in a power source)

CRISPR-Cas

Gene editing technology allowing scientists to alter, delete, or replace specific sections of DNA

Polymerase chain reaction (PCR)

A technique to create many copies of a specific, desired section of DNA

What are the steps of PCR?

1. Heat/denature the DNA

2. Primers anneal to the DNA via complementary base pairings, determining what is amplified

3. Taq polymerase elongates the strand by adding new nucleotides

**This is performed 30 to 35 times to generate 1 billion segments of DNA

How is PCR used to detect pathogens?

Primers bind to DNA from certain pathogens (ex: COVID DNA), often called NAATs in healthcare

Nucleic Acid Amplification Tests (NAATs)

Tests using PCR to amplify pathogen DNA to determine the presence of that pathogen (i.e. a + result indicates the presence of COVID DNA in the sample)

What are the pros of NAATs?

Pathogen-specific, accurate

What are the cons of NAATs?

Can take hours for the PCR reaction (longer than at-home COVID tests)

Precision medicine

Treatment tailored to the person’s body, genome, lifestyle, etc.

What does precision medicine require?

Sequencing of the full genome, seen as the “future” of medicine

Which PCR step involves the binding of primers to separated DNA strands?

Annealing

How do we design a NAAT specific for COVID-19 and not the influenza virus?

Use primers that match COVID-19 DNA