M1 Flashcards
Introduction to Genetic Genealogy
4 Main Reasons People Take a DTC test
- Curious about Biographic Origins/Ancestry
- Looking for Genetic Relatives/Genetic Genealogy
- Health and Nutrition Insights
- Professional Genealogists using DTC test to back up Genealogical Research
Forensic DNA Analysis involves …
TYPE of DNA
- STRs ( short tandem repeats) tetranucleutides
- 17-29 Markers
- Non-Coding
TECHNOLOGY
- PCR Amplification & Capillary Electrophoresis
DATA GENERATED
- Electropherogram
DATA BASE UPLOAD to
- CODIS/National Criminal DNA Database
COMPARED to
- Offender, Arrestee, Forensic, and Reference profiles
RESULTS
- CODIS hit
Comparison to Reference Profiles
Consumer DNA Testing involves…
TYPE OF DNA
- SNPs (single nucleotide polymorphisms)
- 60,000-1,000,000 SNP Markers
- CODING region of genome
- Bio-Geographic Ancestry/Genetic Relatedness/Phenotypic Informative
TECHNOLOGY
- Global Screening Array (GSA) / Next Generation Sequencing
DATA GENERATION
- FASTQ File
DATABASES
- Public Genetic Genealogy Databases
COMPARED to
- General Users i.e., members of the public
RESULTS
- Ancestry Composition
- DNA Relatives
DTC test Upload Steps
- Take Consumer Test
or if you already have taken - Download Raw DNA Data and Save it!
- Upload DNA Data File to
- My Heritage DNA
- Family Tree DNA
- GEDmatch
Consumer DNA Companies that allow Law Enforcement searches
GEDmatch and FamilyTree DNA
Ethics Issues of DNA Testing
- “Family Secrets” revealed
- Unknown Genetic Relatives discovered
- Adoption revealed
- Donor Conception revealed
- Infidelity revealed
- You are consenting to your DNA being analyzed
– Is you DNA really YOUR DNA?
DNA Testing Ethic Considerations
- Genetic Privacy
- Unwanted Information
- Informed Consent
- Ethnically Ambiguous results devoid of cultural connections
- Psychological Trauma
- Learning scary Health Info - w/o guidance of a health professional
- DTC DNA Testing Companies PROFIT from you data
- Hacking
- Privacy Policies & Terms of Use Agreements are constantly changing
Genetic Genealogy is
the application of genetics to traditional genealogy.
- used as an additional type of EVIDENCE in genealogy
CDT Testing + Genealogy = Genetic Genealogy
TYPES of DNA
- Autosomal (atDNA)
- most widely studied & understood
- Y Chromosomal (YDNA)
- Sex Chromosome
- X Chromosomal (XDNA)
- Sex Chromosome
- Mitochondrial (mtDNA)
Genetic Genealogy first coined as a term
by Tom Siegfried in Dallas Morning (20 Feb 1989)
- Titled “Genetic Genealogy and the Search for ‘Eve’”
Breaks in the DNA lineage may indicate
where a FATHER is NOT what he claims or knows to be
Genetic Inheritance
- 23 pairs Chromosomes
- 46 Total chromosomes
- Receive 1 chromosome from each parent
- same size & composition, but variations in genes
- 1-22 = Autosomal DNA (atDNA)
- Same size & composition
- XX or XY = sex chromosomes
- X is BIGGER than Y
** Men inherit SLIGHTLY MORE DNA from their Moms than their dads - A person inherits 50% DNA from each parent BUT not and even 50%
- It is RANDOM
Genetic Inheritance Measurement for Genetic Genealogy
A centimorgan (cM)
Centimorgan (cM)
is a unit of measure for the frequency of genetic recombination (used for genetic genealogy)
- 1 centimorgan is equal to 1% change that 2 markers on a chromosome will become separated from one another DUE to a RECOMBINATION event during MEIOSIS
- On average, 1 centimorgan corresponds to roughly 1 million BASE PAIRS in the human genome
Genetic Recombination
- Randomly shuffled inherited autosomal DNA from distant ancestors
- Pieces of DNA are broken and recombined to produce new combinations of alleles
- Creates genetic diversity at the level of genes that reflects differences in the DNA sequences of different organisms.
Measure DNA in BASEPAIRS
- Autosomal 1-22 Pairs of Chromosomes = 2,875,002,522 BASE PAIRS
- X Chromosomes = 156,040,895 BASE PAIRS
- Y Chromosomes = 57, 277,415 BASE PAIRS
Measure DNA in Genes
NOT ALL GENES IDENTIFIED YET
- Autosomal Chr 1-22 = 24,211 genes
- X Chr = 1,100
*Y Chr = 101
Half Identical Regions (HIR)
is where 2 people shar a segment of DNA on just 1 of their chromosomes.
Fully Identical Regions (FIR)
is where 2 people share segments of DNA on both copies of of their 2 chromosomes
** Full siblings will share on HALF identical & FULL identical REGIONS
FULL siblings total cM = ~3,400
Identical By Descent (IBD)
describes a matching segments of DNA shared by 2 or more people that has been inherited from a COMMON ancestor W/O any intervening RECOMBINATION
- Segments are confirmed when a COMMON ANCESTOR is found through MULTIPLE matches with the same ANCESTOR (Triangulation)
- Segments are considered to match if ALL the ALLELES on a PATERNAL or MATERNAL CHROMOSOME are IDENTICAL and if the MINIMUM threshold conditions set by the TESTING company have be met.
Identical By Chance (IBC)
You match/share a DNA segment w/someone because of RANDOM inheritance patterns (sometimes known as FALSE positives)
** IBC segments tend to be SMALLER segments, & will NOT match others in a TRIANGULATED group.
Identical By Population (IBP)
You match/share a DNA segment w/someone because that particular segment is found in HIGH FREQUENCIES in a given population, therefore you could have inherited that segment from MULTIPLE ancestors.
- IBP segments tend to be SMALLER segments from known ENDOGAMOUS POPULATIONS.
Identical By State (IBS)
Obsolete term – opposite of IBD
** Was often used in the context of “I can’t identify the ancestor, so they must be IBS”
Genetic Genealogy Applications
- Biological Parentage Identification
- Adoption
- Donor Conception
- NPE (Non-Paternity Event)
- Criminal Investigations
- Unidentified Human Remains
- Missing Persons
— Foundlings & Living Does - Historical Investigations
- Mass Graves
- Heirs to land, titles, inheritances etc.
- Ancestral Artefacts
- Emigration/Citizenship
- Eligibility for Societies (e.g., DAR)
GEDMatch History
- Curtis Rogers & John Olsen created in 2010
- Created as an outgrowth of a SURNAME DNA Project
- Collaborated to automate the MAPPING and MATCHING of family trees
- Bought by Verogen now QIAGEN in 2019
GEDMatch Kit Diagnostic Utility Tool
Analyzes DNA Kit
Access Level
- Private “public access of NO”
- Opt-in “public access of YES - including LE”
- Opt-out “public access of YES”
- Research “Public access of RESEARCH”
- Law Enforcement kit - “Public access of Research admin locked”
Status
- “Good”
** Samples that are processed using Whole Genome Sequencing (WGS) may result in a “MATCHY”
*** the kit will match w/a LARGE amount of other kits & many may be FALSE matches
USABLE SNPs
TOTAL MATCHES to KIT
GEDMatch Are Your Parents Related? Tool (AYPR)
Begin
In default setting - “Graphic and Positions”
** If match is not made 1st time try “Position Only”
- is a utility that searches the genome for Runs of Homozygosity (ROH), regions where DNA is identical on BOTH chromosomes.
- This is NOT a tool to identify ENDOGAMY although it may produce positive results in an endogamous population.
- PRESUMPTIVE not confirmatory test
GEDMatch AYPR Tool Parents are probably NOT related w/in recent generations
- For this result SCREENSHOT w/graphics set to “POSITION ONLY” unless the graphics show SIGNIFICANT segments in GREEN
** segments significantly LARGER than a THIN green line
GEDMatch Parents are probably RELATED w/in the LAST several generations
- For this result SCREENSHOT w/graphics set to “GRAPHICS and POSITION”
- Relationship predictor tools are NOT relevant to, or accurate for, interpreting the results from the AYPR tool
- The amount of shared DNA between the parents of a person who receives a positive result is approximately 4 times HIGHER than the total ROH inherited by the user
*** HOWEVER, this calculation alone is NOT reliable indicator of the parents’ relationship
GEDMatch One-To-Many Tool Filters
- Filter By:
Autosomal (1st)
X (2nd) - With this Offset
- tells the tool which match to
start w/#1, 501, 1001, etc.
- tells the tool which match to
- With this Limit
- is the number of matches to
display w/in this search
- is the number of matches to
- cM Size
- is centimorgan size & indicates
the SMALLEST amount of
shared DNA in centimorgans to
display- Matches UNDER 7 cM have a
HIGHER chance of being IBC
- Matches UNDER 7 cM have a
- is centimorgan size & indicates
- Tag Groups
- will display matches w/the color
associated w/the primary kit in
which a TAG was used
- will display matches w/the color
- Overlap Cutoff
- shows the amount of SNPs that
overlap between the primary kit
and a match’s kit - Select All
- will select ALL kits & include them
when running another tool
through the VISUALIZATION
options - Select All w/GEDCOMS
- will select ALL the kits that have GEDcoms to use w/the tools in the Visualization Options
GEDMatch One-To-Many Results
- Kit
- This is the kit number associated w/the match
- This information along w/the SOURCE column can be useful when trying to determine if the test taker has a PUBLIC tree available for REFERENCE - Name (*=>alias)
- This is typically the test takers name NOT always
- Sometimes a test taker alias
- Sometimes the name is NOT the actual test taker. Could be the KIT MANAGER - Email
- This is the email of the kit manager which may NOT be the test taker - GED/WikiTree
- the test taker or kit manger may have included a family tree in the form of a GEDcom file or link to a Wikitree - SEX
- The sex of the test taker is listed in the column - Autosomal Total cM
- This is the total amount of DNA shared between the primary kit & the match. - Autosomal Largest segment
- this is the largest segment shared between the primary kit and the match - GEN - stands for generation
- X-DNA Total cM
- This is the total amount of X-DNA shared between the primary kit and the match - X - DNA Largest segment
- This is the LARGEST segment of X-DNA shared between the primary kit and the match - Mt Haplogroup
- the test taker may list the mitochondrial haplogroup - Y Haplogroup
- the test taker may list the Y haplogroup in this column - Source
- This indicates which testing company was used by the match - Overlap
- This number represents the amount of overlap of SNPs between the 2 kits - Age
- this is the number of DAYS the kit has been on GEDMatch.
Function of Forensic DNA Analysis AND Forensic Investigative Genetic Genealogy:
to perform an objective scientific analysis of forensic evidence for the purpose of Human Identification
FIGG Case File Workflow
Case Assessment
- Violent Crimes - Homicide & Sexual Assault
- UHRs
- STR Profile Generated
- NO Hits in Database (incl. FDS)
THEN
- Sufficient DNA extract remaining from ORIGINAL extraction
OR - Return to ORIGINAL evidence item & generate NEW DNA extract
- Quantity & Quality
FIGG Case Workflow
Case Assessment - Questions to Consider
VERY IMPORTANT
* What is the DNA quantity & quality?
* WHEN was the EXTRACT last quantitated?
* Does the extract NEED to be rehydrated/reconstituted?
*What is the VOLUME of extract REMAINING?
* Where is the DNA extract?
*Is WHOLE sample consumption allowed/authorized?
FIGG Case File Workflow
SNP Sequencing
- SNPs = 600,00 -> 1,000,000 MARKERS
- Next Generation Sequencing (NGS) now admitted in court
- SNP Microarray
- Targeted SNP Kit – Kintelligence
- Whole Genome Sequencing
FIGG Case File Workflow
Genetic Genealogy
- RAW DNA data uploaded into GEDmatch PRO or Gene by Gene
- LE search ONLY allowed in GEDMatch & FTDNA
- Matching segments betwe SNP 1 & SNP 2
- The more cM shared the more likely related
- GEDmatch Tool One-To-Many
– Relationship Probabilities for shared cM
*Verify identities of DNA matches:
- through email provided in GEDmatch
- Online sites such as Google, White Pages, Been Verified, truthfinder
- Social Media
FIGG Case File Workflow
Tree Building
- Adhere to Genealogy Standards
- Build back generations to find MRCA (Most Recent Common Ancestor) on paternal and maternal lines.
1 Misconception about FIGG
FIGG is NOT separate
- FIGG is NOT separate from Forensics
FIGG Case File Workflow
Review/Report
- Every step of a FIGG investigation should be DOCUMENTED
- Every genetic genealogy tool performed
- Genealogical records used to build family trees
- Final report detailing the FIGG analysis should be provided
- Any other competent FIGG practitioner should be able to INTERPRET the findings & reach the SAME CONCLUSION
- Administrative & Technical Review
- Proposed Candidate Name(s) provided to LE Agency
- Reference DNA Sample
- Suspect
- Overt or Covert DNA Collection
- UHR
- Closest Living Relative DNA Collection
2 Misconception about FIGG
FIGG is just an …
JUST an INVESTIGATIVE LEAD
FIGG will never be introduced to court proceedings because the STR profile is the evidence & FIGG practitioners will not need to testify
3 MISCONCEPTION about FIGG
LE & FIGGs are accessing…
- LE & FIGG practitioners are accessing all DTC Genetic Databases
4 Misconception about FIGG
Suspects are arrested…
- Suspects are arrested based ONLY on FIGG leads
