FIGG - Forensic investigative genetic geneology

Question 1

What is figg and how does it work?

Answer 1

• forensic investigative genetic geneology
• exploits the similarity between sibling and parent
• familial searches, uses NDNAD
• the step after not getting a match on the data base

Question 2

examples of intelligence tools when there’s no match on the database

Answer 2

• familial searches
• Y STR
• rare allele mapping
• FIGG

Question 3

what are the 3 types of matches produced?

Answer 3

scene to scene
person to scene
person to person

Question 4

what is the NDNAD?

Answer 4

the national DNA database = holds DNA info of unsolved crimes with no matches
- identifies people with the genetic potential to be related to the person who left the crime scene profile

Question 5

reasons for a non match on the NDNAD

Answer 5

• moved abroad
• person may have died
• person in prison or hospital institution
• person may have re offended

Question 6

what does the conventional method of profiling aka DNA 17 use?

Answer 6

use STRs - have ethical problems
- used for direct matches
- repeating unit called the motif

Question 7

what is an STR?

Answer 7

• short tandem repeat (aka mini satellites
• non coding contributor to genes
• 9-80 bp range
• 60% of the non coding DNA are short repeating units

Question 8

current day use for a match

Answer 8

SNPs - single nucleotide polymorphism- used for indirect kinship matches
- locations where mutations usually occur

Question 9

how does the use of SNPs work to provide a match

Answer 9

• profile run against 23 and me databases and uses family trees
• gets to a point of common ancestry and works from there (eg for cousins = grandparents)
• calculates genetic similarity - expecting low results
• Joseph Kappen 1973 = first one

Question 10

Y-STR matches

Answer 10

• a male’s Y -STR must match that of the crime scene sample – if not then all of his male relatives cannot be an offender

Question 11

Mitochondrial DNA matches

Answer 11

• a female’s mitochondrial DNA must match that of the crime scene sample – if not then all of her female relatives cannot be an offender – does not eliminate her father

Question 12

parent child match

Answer 12

profile has at least one matching DNA band at each of the 17 loci

Question 13

sibling match

Answer 13

produces a list with the number of matching bands
- can be thousands so need to be prioritised

Question 14

how is the list of a sibling match prioritised on?

Answer 14

• ethnic appearance
• age (parent/ child no more than 15 yr diff, sibling no more than 20 yr diff)
• geography

must re prioritise when new info becomes available