DNA basics
In a DNA molecule, this nitrogenous base pairs with adenine.
What is thymine?
This is the most common fingerprint pattern type, accounting for roughly 60% to 65% of all occurrences.
What is a loop?
A DNA extract produces weak amplification, but the result improves when the extract is diluted. This observation can suggest the presence of this problem.
What is PCR inhibition?
A forensic laboratory runs this sample known to produce a positive result alongside evidence samples to demonstrate that the analytical system is functioning properly.
What is a positive control?
This vapor tight container is used for the collection of samples that may have a ignitable liquid.
What is a metal can?
This step in DNA extraction breaks open cells and nuclei so that DNA can be released into the solution.
What is cell lysis?
Used on non-porous surfaces, this technique involves heating ethyl cyanoacrylate inside an airtight chamber to polymerize and form a hard, white crust over latent residues.
What is superglue/cyanoacrylate ester fuming?
The effect seen when random sampling of small quantities of DNA produce unusually variable peak heights and even cause an expected allele to disappear.
What are stochastic effects?
This broad quality-system concept encompasses the policies, procedures, monitoring, documentation, and other activities designed to provide confidence that laboratory work meets specified requirements.
What is quality assurance?
This is the process by which a material is decomposed or broken down into simpler molecular compounds by the effects of heat alone.
What is pyrolysis?
A person has alleles 12 and 15 at an STR locus. This term describes the person's genotype at that locus.
What is heterozygous.
In friction ridge identification, level 1 detail evaluates overall pattern flow and ridge orientation, whereas Level 2 details examine these specific individual ridge events.
What are minutiae?
Unlike autosomal STRs, these STR markers are located on this chromosome and are particularly useful for examining male DNA in certain mixtures.
What is the Y chromosome?
The long form name for the acronym ANAB.
What is ANSI (American National Standards Institute) National Accreditation Board?
This is the dominant profile of gasoline?
What is aromatic (patroleum distilate)?
Before STR amplification, forensic laboratories commonly perform this measurement to estimate how much DNA is available for amplification.
What is DNA quantitation?
This rare composite pattern features two separate loop formations combined within the same impression, often resembling the letter "S".
What is a double loop whorl?
A small peak one repeat shorter than a much larger STR peak may be produced by this PCR artifact.
What is stutter?
This QC measure involves showing that a method works appropriately.
What is verification?
Fatty acid methyl esters are compounds often found in this product?
What is biodiesel fuel (vegetable oil)?
This laboratory technique produces millions of copies of selected DNA regions, allowing STRs to be analyzed from relatively small amounts of starting material
What is PCR?
This specialized fluorescent dye is often applied after superglue fuming and viewed under an alternate light source (ALS) to visualize prints on difficult, high-background surfaces
What is rhodamine 6G (or basic yellow/RAM)?
At an autosomal STR locus, four distinct alleles are observed in a mixture. Assuming no artifacts or unusual circumstances, this observation establishes at least this many contributors.
What are two contributors?
This is the standard to which forensic labs are accredited to.
What is ISO 17025
Both IR and Raman Spectroscopy depend on molecular vibrations to assist with identification of salts in explosive cases. However Raman in technique is based on scattering while IR is based on this.
What is absorbance?