M2 Flashcards
FIGG is adjacent to Forensic DNA Analysis, and needs to
fit in w/forensic needs, standards, etc.
FIGG uses forensic evidence that is the
custody of the LE agency/Forensic lab
Forensic Labs are better suited to make decisions about:
- Sample quality and quantity
- Whole sample consumption
- Maintaining chain of custody
- Choosing sequencing method
*Maintaining ownership of work products (genetic data/trees/records) - STR Profile Comparisons
FIGG Workflow Checklist
- Violent Crime or UHR & meets Policy, laws, and Terms of Service
- STR Profile Developed
- Uploaded to CODIS/National Database
- No Hits
- FDS performed (if permitted by law)
- Authorization to perform FIGG
- Is there Sufficient DNA extract remaining from original extraction
or - Return to original evidence item & generate new DNA extract
DNA Quality & Quantity Evaluation
- What is the DNA quantity & quality?
*When was the extract last quantitated? - Does the extract need to rehydrated?
- What is the volume of extract remaining?
- Where is the DNA extract?
- Is whole sample consumption allowed?
3 SNP Technology Methods
- SNP Microarray
- Whole Genome Sequencing
- Target Kit - Kintelligence
SNP Microarray
EVALUATES
~600,000 SNPs
AMOUNT of DNA NEEDED
~200 ng (but has shown to work with ~1ng)
COST
Cheapest $500-$700
EFFECTIVNESS
Not good with DEGRADED DNA
Whole Genome Sequencing (WGS)
EVALUATES
Whole
AMOUNT of DNA NEEDED
50ng-50pg
COST
Most Expensive $1,500-$8,000
EFFECTIVENESS
Recommended for DEGRADED DNA
Target Kit - Kintelligence
by Verogen
EVALUATES
~10,230 SNPs
AMOUNT of DNA NEEDED
1ng
COST
Mid-Range $1,000-$1,500
EFFECTIVENESS
Future In-House (Crime Lab) Capability
Questions to Consider about SNP Technology Methods
- What is the best method for the sample?
– Quality & Quantity of DNA - Is this the last drop of DNA in the case?
–Whole Sample Consumption - authorized?
– Recommendation – WAIT! - Cost of Sequencing Method?
– Funding Sources - Outsourcing: Risks & Benefits
Next Generation Sequencing (NGS)
- Not a “new” science
- Well established/studied
- The APPLICATION of the method is NEW
SNP Microarray most common Chip
Lumina Global Screening Array
SNP Microarray instrument
I-Scan
* Most public labs do not have
SNP Microarray
High imputation accuracy at minor allele frequencies of
> 1% across ALL 26 1000 Genomes Project Reference Sample
Whole Genome Sequencing (WGS)
instrument
NovaSeq 6000
Whole Genome Sequencing (WGS)
“sequencing coverage” or “sequencing depth” = the number of
unique sequencing reads that align to a region in a reference genome or de novo assembly
Whole Genome Sequencing (WGS)
A 30x human genome means that the reads align
to any given region of the reference about 30 times, on average.
** scans back and forth 30 times