Exam 2

Question 1

A. When analyzing DNA from a single bloodstain using a typical multiplex kit and CE, what is the minimum set of samples (each a separate injection) that must be loaded on the instrument to perform genotyping?

Answer 1

The evidence (extracted from the bloodstain)
The allelic ladder [accepted external size standard]

Question 2

B. What additional type or types of sample are likely to be included for quality control?

Answer 2

Positive and negative PCR controls

Question 3

The typical CE genetic analyzer uses a capillary made of

Answer 3

Glass

Question 4

What is a potential cause of peak shift affecting CE analysis of STR alleles?

Answer 4

Building up of electrical charge on the capillary wall or change in temperature

Question 5

An instrument such as the Applied Biosystems 3100 genetic analyzer, the operator inputs the sample information as part of the _________ and the electrophoresis conditions as part of the _____________.

Answer 5

Plate record, run module

Question 6

Dye standards must be periodically run through a CE genetic analyzer so that it can correctly perform the

Answer 6

Spectral calibration

Question 7

What information from an STR electropherogram indicates that a peak is pull-up?

Answer 7

It is the same length as an allele, especially a taller peak, in an adjacent color/channel
It is different from a normal-looking set of alleles present for that locus.

Question 8

What information from an STR electropherogram indicates that a peak is stutter?

Answer 8

The peak is one repeat shorter than a normal-looking allele, and usually <15% the height of the true allele