evidence for evolution - gel electrophoresis & DNA sequencing

What is DNA profiling?

Technique used to identify individuals based on the banding pattern of fragments of DNA

Steps of Gel Electrophoresis

What is DNA Ladder and its use for comparison

Ladder contains segments of DNA with known lengths

Results from unknown sample are compared to ladder to determine length of DNA strands in the sample

use of micropipettes in gel electrophoresis:

used to fill wells (depressions in the gel) for gel electrophoresis

What methods allows us to visualise DNA (see the banding patterns)

• Ethidium bromide: (known carcinogen) can be added to the gel, as the DNA moves through it picks up some of the chemical. Upon completion of the run, special UV light is shone on gel and DNA fluoresce

• Methylene Blue: dye that binds to DNA, areas that contain DNA stain a deeper blue & are visible to naked eye

• DNA probe: Short sections of single strand of DNA with a radioactive or fluorescent molecule that binds to DNA being tested

what is DNA sequencing?

DNA sequencing is a process used to establish the precise order of nucleotides (bases) along a piece of DNA.

reason to sequence:

 Once a sequence has been obtained different samples can be compared - one way of comparison is gel electrophoresis.

ethical consideration for use of genetic information:

• Autonomy: respect for the right to be self-determining and to choose whether or not to be tested and, if tested, to know and share the information. It also includes the right on an individual to decide their own future, independent of genetic information.

• Confidentiality: the use of genetic information is treated sensitively, and is accessed only by those who are authorised to access it

• Equity: the right to fair and equal treatment regardless of genetic information

• Privacy: the right to be ‘left alone’ and to make decisions regarding genetic testing and the resulting information, independent of others