artefacts

Question 1

what is an artefact?

Answer 1

things that happen during testing that cannot be reproduced.
not associated with the sample

Question 2

stutter

Answer 2

small tiny peaks next to alleles. example of a biological artefact
occurs during PCR
don’t get labelled as are filters in the software

Question 3

spikes and blobs

Answer 3

spikes = tall very narrow peaks seen in normal range. example of a instrumental artefact
blobs = same but short and fat
can be caused due to voltage spikes when running through the genetic analyser

Question 4

peak height imbalance

Answer 4

height of smaller peak / height of taller peak x 100
can be due to: different contribution levels or mixtures

Question 5

degradation

Answer 5

deterioration of DNA
bigger fragments are better targets for degradation

Question 6

inhibition

Answer 6

caused by poor PCR amplification
larger DNA pieces are harder to amplify as take more time to go through capillaries
leads to smaller peaks as moves to the right of the EPG
extreme = drop out

Question 7

drop out

Answer 7

allele drop out –> test failure = incomplete profile given creates a ski slope pattern on EPG

Question 8

baseline noise

Answer 8

often hard to distinguish but implements a minimum peak height threshold
anything below is discounted, no conclusion can be drawn

Question 9

mutations

Answer 9

mutations at the primer binding side

Question 10

micro variants

Answer 10

alleles that contain incomplete repeat units = complicates process.