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Genetic Genealogy > M1 > Flashcards

M1 Flashcards

Introduction to Genetic Genealogy

1
Q

4 Main Reasons People Take a DTC test

A
  1. Curious about Biographic Origins/Ancestry
  2. Looking for Genetic Relatives/Genetic Genealogy
  3. Health and Nutrition Insights
  4. Professional Genealogists using DTC test to back up Genealogical Research
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2
Q

Forensic DNA Analysis involves …

A

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

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3
Q

Consumer DNA Testing involves…

A

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
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4
Q

DTC test Upload Steps

A
  1. Take Consumer Test
    or if you already have taken
  2. Download Raw DNA Data and Save it!
  3. Upload DNA Data File to
    - My Heritage DNA
    - Family Tree DNA
    - GEDmatch
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5
Q

Consumer DNA Companies that allow Law Enforcement searches

A

GEDmatch and FamilyTree DNA

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6
Q

Ethics Issues of DNA Testing

A
  • “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?
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7
Q

DNA Testing Ethic Considerations

A
  • 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
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8
Q

Genetic Genealogy is

A

the application of genetics to traditional genealogy.
- used as an additional type of EVIDENCE in genealogy

CDT Testing + Genealogy = Genetic Genealogy

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9
Q

TYPES of DNA

A
  • Autosomal (atDNA)
  • most widely studied & understood
  • Y Chromosomal (YDNA)
  • Sex Chromosome
  • X Chromosomal (XDNA)
  • Sex Chromosome
  • Mitochondrial (mtDNA)
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10
Q

Genetic Genealogy first coined as a term

A

by Tom Siegfried in Dallas Morning (20 Feb 1989)

  • Titled “Genetic Genealogy and the Search for ‘Eve’”
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11
Q

Breaks in the DNA lineage may indicate

A

where a FATHER is NOT what he claims or knows to be

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12
Q

Genetic Inheritance

A
  • 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
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13
Q

Genetic Inheritance Measurement for Genetic Genealogy

A

A centimorgan (cM)

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14
Q

Centimorgan (cM)

A

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
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15
Q

Genetic Recombination

A
  • 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.
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16
Q

Measure DNA in BASEPAIRS

A
  • 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
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17
Q

Measure DNA in Genes

A

NOT ALL GENES IDENTIFIED YET

  • Autosomal Chr 1-22 = 24,211 genes
  • X Chr = 1,100

*Y Chr = 101

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18
Q

Half Identical Regions (HIR)

A

is where 2 people shar a segment of DNA on just 1 of their chromosomes.

19
Q

Fully Identical Regions (FIR)

A

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

20
Q

Identical By Descent (IBD)

A

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.
21
Q

Identical By Chance (IBC)

A

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.

22
Q

Identical By Population (IBP)

A

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.
23
Q

Identical By State (IBS)

A

Obsolete term – opposite of IBD

** Was often used in the context of “I can’t identify the ancestor, so they must be IBS”

24
Q

Genetic Genealogy Applications

A
  • 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)
25
Q

GEDMatch History

A
  • 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
26
Q

GEDMatch Kit Diagnostic Utility Tool

A

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

27
Q

GEDMatch Are Your Parents Related? Tool (AYPR)

A

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
28
Q

GEDMatch AYPR Tool Parents are probably NOT related w/in recent generations

A
  • 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
29
Q

GEDMatch Parents are probably RELATED w/in the LAST several generations

A
  • 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
30
Q

GEDMatch One-To-Many Tool Filters

A
  1. Filter By:
    Autosomal (1st)
    X (2nd)
  2. With this Offset
    • tells the tool which match to
      start w/#1, 501, 1001, etc.
  3. With this Limit
    • is the number of matches to
      display w/in this search
  4. 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
  5. Tag Groups
    • will display matches w/the color
      associated w/the primary kit in
      which a TAG was used
  6. Overlap Cutoff
    - shows the amount of SNPs that
    overlap between the primary kit
    and a match’s kit
  7. Select All
    - will select ALL kits & include them
    when running another tool
    through the VISUALIZATION
    options
  8. Select All w/GEDCOMS
    - will select ALL the kits that have GEDcoms to use w/the tools in the Visualization Options
31
Q

GEDMatch One-To-Many Results

A
  1. 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
  2. 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
  3. Email
    - This is the email of the kit manager which may NOT be the test taker
  4. 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
  5. SEX
    - The sex of the test taker is listed in the column
  6. Autosomal Total cM
    - This is the total amount of DNA shared between the primary kit & the match.
  7. Autosomal Largest segment
    - this is the largest segment shared between the primary kit and the match
  8. GEN - stands for generation
  9. X-DNA Total cM
    - This is the total amount of X-DNA shared between the primary kit and the match
  10. X - DNA Largest segment
    - This is the LARGEST segment of X-DNA shared between the primary kit and the match
  11. Mt Haplogroup
    - the test taker may list the mitochondrial haplogroup
  12. Y Haplogroup
    - the test taker may list the Y haplogroup in this column
  13. Source
    - This indicates which testing company was used by the match
  14. Overlap
    - This number represents the amount of overlap of SNPs between the 2 kits
  15. Age
    - this is the number of DAYS the kit has been on GEDMatch.
32
Q

Function of Forensic DNA Analysis AND Forensic Investigative Genetic Genealogy:

A

to perform an objective scientific analysis of forensic evidence for the purpose of Human Identification

33
Q

FIGG Case File Workflow
Case Assessment

A
  • 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
34
Q

FIGG Case Workflow
Case Assessment - Questions to Consider

A

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?

35
Q

FIGG Case File Workflow
SNP Sequencing

A
  • SNPs = 600,00 -> 1,000,000 MARKERS
  • Next Generation Sequencing (NGS) now admitted in court
  • SNP Microarray
  • Targeted SNP Kit – Kintelligence
  • Whole Genome Sequencing
36
Q

FIGG Case File Workflow
Genetic Genealogy

A
  • 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

37
Q

FIGG Case File Workflow
Tree Building

A
  • Adhere to Genealogy Standards
  • Build back generations to find MRCA (Most Recent Common Ancestor) on paternal and maternal lines.
38
Q

1 Misconception about FIGG

FIGG is NOT separate

A
  • FIGG is NOT separate from Forensics
38
Q

FIGG Case File Workflow
Review/Report

A
  • 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
39
Q

2 Misconception about FIGG

FIGG is just an …

A

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

40
Q

3 MISCONCEPTION about FIGG

LE & FIGGs are accessing…

A
  • LE & FIGG practitioners are accessing all DTC Genetic Databases
41
Q

4 Misconception about FIGG

Suspects are arrested…

A
  • Suspects are arrested based ONLY on FIGG leads
42
Q
A

Genetic Genealogy (6 decks)

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