Debbie Kennett 🧬🌳
@debbiekennett.bsky.social
DNA, genetic genealogy, family history. forensics. Honorary Research Fellow at UCL. All views my own.
Reposted by Debbie Kennett 🧬🌳
Great work by Harel Ismach, a student in my group, who has led the data analysis. Thanks to collaborators @gilig.bsky.social and @debbiekennett.bsky.social. The register data was made available by Israel's Central Bureau of Statistics.
August 12, 2026 at 8:18 PM
Great work by Harel Ismach, a student in my group, who has led the data analysis. Thanks to collaborators @gilig.bsky.social and @debbiekennett.bsky.social. The register data was made available by Israel's Central Bureau of Statistics.
Reposted by Debbie Kennett 🧬🌳
Nevertheless, our results are important because they apply to genealogical data *already accessible* to law enforcement in many countries, without relying on commercial providers.
Our results should inform regulators and practitioners of FIGG, as well as quantify biobank privacy risks.
10/10
Our results should inform regulators and practitioners of FIGG, as well as quantify biobank privacy risks.
10/10
August 12, 2026 at 8:18 PM
Nevertheless, our results are important because they apply to genealogical data *already accessible* to law enforcement in many countries, without relying on commercial providers.
Our results should inform regulators and practitioners of FIGG, as well as quantify biobank privacy risks.
10/10
Our results should inform regulators and practitioners of FIGG, as well as quantify biobank privacy risks.
10/10
Reposted by Debbie Kennett 🧬🌳
Key limitations:
* Finding a match does not guarantee identification
* Many relatives missed because of the limited time depth of the register
* Data errors (clerical, adoption, non-paternity, gamete donation, relationship misclassification, MZ twins)
* Generalizability to other countries
9/10
* Finding a match does not guarantee identification
* Many relatives missed because of the limited time depth of the register
* Data errors (clerical, adoption, non-paternity, gamete donation, relationship misclassification, MZ twins)
* Generalizability to other countries
9/10
August 12, 2026 at 8:18 PM
Key limitations:
* Finding a match does not guarantee identification
* Many relatives missed because of the limited time depth of the register
* Data errors (clerical, adoption, non-paternity, gamete donation, relationship misclassification, MZ twins)
* Generalizability to other countries
9/10
* Finding a match does not guarantee identification
* Many relatives missed because of the limited time depth of the register
* Data errors (clerical, adoption, non-paternity, gamete donation, relationship misclassification, MZ twins)
* Generalizability to other countries
9/10
Reposted by Debbie Kennett 🧬🌳
What is the probability of having *two* (or more) relatives in the database?
This is important, as it is often the intersection of the family trees of multiple matches that leads to identification.
The match rate naturally decreases, although not as much for the very large databases.
8/10
This is important, as it is often the intersection of the family trees of multiple matches that leads to identification.
The match rate naturally decreases, although not as much for the very large databases.
8/10
August 12, 2026 at 8:18 PM
What is the probability of having *two* (or more) relatives in the database?
This is important, as it is often the intersection of the family trees of multiple matches that leads to identification.
The match rate naturally decreases, although not as much for the very large databases.
8/10
This is important, as it is often the intersection of the family trees of multiple matches that leads to identification.
The match rate naturally decreases, although not as much for the very large databases.
8/10
Reposted by Debbie Kennett 🧬🌳
Unexpectedly, the match rate barely increases beyond 5th-degree (2nd cousins).
This is probably because the common ancestors of third cousins usually lived before the country's foundation.
Implication: whenever relatives are found in the database, they are usually not too distant.
7/10
This is probably because the common ancestors of third cousins usually lived before the country's foundation.
Implication: whenever relatives are found in the database, they are usually not too distant.
7/10
August 12, 2026 at 8:18 PM
Unexpectedly, the match rate barely increases beyond 5th-degree (2nd cousins).
This is probably because the common ancestors of third cousins usually lived before the country's foundation.
Implication: whenever relatives are found in the database, they are usually not too distant.
7/10
This is probably because the common ancestors of third cousins usually lived before the country's foundation.
Implication: whenever relatives are found in the database, they are usually not too distant.
7/10
Reposted by Debbie Kennett 🧬🌳
Results:
The match rate is the proportion of people with at least one relative (a "match") in the database.
For a database covering 1% of the country, the match rate is ~25%. For a database covering 10% of the country, the rate is 68%.
6/10
The match rate is the proportion of people with at least one relative (a "match") in the database.
For a database covering 1% of the country, the match rate is ~25%. For a database covering 10% of the country, the rate is 68%.
6/10
August 12, 2026 at 8:18 PM
Results:
The match rate is the proportion of people with at least one relative (a "match") in the database.
For a database covering 1% of the country, the match rate is ~25%. For a database covering 10% of the country, the rate is 68%.
6/10
The match rate is the proportion of people with at least one relative (a "match") in the database.
For a database covering 1% of the country, the match rate is ~25%. For a database covering 10% of the country, the rate is 68%.
6/10
Reposted by Debbie Kennett 🧬🌳
FIGG simulation:
We designated a random subset of the population as the "database".
For each person in the database, we used the register to track all of their relatives up to 7th degree (eg, 3rd cousins). This gave us the list of people who would have one or more relatives in the database.
5/10
We designated a random subset of the population as the "database".
For each person in the database, we used the register to track all of their relatives up to 7th degree (eg, 3rd cousins). This gave us the list of people who would have one or more relatives in the database.
5/10
August 12, 2026 at 8:18 PM
FIGG simulation:
We designated a random subset of the population as the "database".
For each person in the database, we used the register to track all of their relatives up to 7th degree (eg, 3rd cousins). This gave us the list of people who would have one or more relatives in the database.
5/10
We designated a random subset of the population as the "database".
For each person in the database, we used the register to track all of their relatives up to 7th degree (eg, 3rd cousins). This gave us the list of people who would have one or more relatives in the database.
5/10
Reposted by Debbie Kennett 🧬🌳
Data:
We used the entire Israeli national population register, documenting all parent-child relationships in all present and past citizens.
After QC, the dataset covered 12.5 million people, among them 10.4 million alive.
Summary stats look reasonable.
4/10
We used the entire Israeli national population register, documenting all parent-child relationships in all present and past citizens.
After QC, the dataset covered 12.5 million people, among them 10.4 million alive.
Summary stats look reasonable.
4/10
August 12, 2026 at 8:18 PM
Data:
We used the entire Israeli national population register, documenting all parent-child relationships in all present and past citizens.
After QC, the dataset covered 12.5 million people, among them 10.4 million alive.
Summary stats look reasonable.
4/10
We used the entire Israeli national population register, documenting all parent-child relationships in all present and past citizens.
After QC, the dataset covered 12.5 million people, among them 10.4 million alive.
Summary stats look reasonable.
4/10
Reposted by Debbie Kennett 🧬🌳
Our research question:
Given a genomic database covering x% of the population of a country, what is the probability that a target person has one or more relatives in the database?
Particularly, we focus on relatives from whom the target can be traced using available genealogical data.
3/10
Given a genomic database covering x% of the population of a country, what is the probability that a target person has one or more relatives in the database?
Particularly, we focus on relatives from whom the target can be traced using available genealogical data.
3/10
August 12, 2026 at 8:18 PM
Our research question:
Given a genomic database covering x% of the population of a country, what is the probability that a target person has one or more relatives in the database?
Particularly, we focus on relatives from whom the target can be traced using available genealogical data.
3/10
Given a genomic database covering x% of the population of a country, what is the probability that a target person has one or more relatives in the database?
Particularly, we focus on relatives from whom the target can be traced using available genealogical data.
3/10
Reposted by Debbie Kennett 🧬🌳
In forensic investigative genetic genealogy (FIGG), law enforcement people upload the DNA of an unknown person (a criminal or unidentified remains) to a consumer genomics database (eg FTDNA), find relatives, and intersect their family trees until reaching an identification.
2/10
2/10
August 12, 2026 at 8:18 PM
In forensic investigative genetic genealogy (FIGG), law enforcement people upload the DNA of an unknown person (a criminal or unidentified remains) to a consumer genomics database (eg FTDNA), find relatives, and intersect their family trees until reaching an identification.
2/10
2/10
Reposted by Debbie Kennett 🧬🌳
New preprint!
Investigative genetic genealogy has revolutionized forensic identification, with hundreds of cases solved to date.
But for any given new case, how likely is genetic genealogy to succeed?
We used a whole-country genealogy to find out!
1/10
www.biorxiv.org/content/10.6...
Investigative genetic genealogy has revolutionized forensic identification, with hundreds of cases solved to date.
But for any given new case, how likely is genetic genealogy to succeed?
We used a whole-country genealogy to find out!
1/10
www.biorxiv.org/content/10.6...
Forensic investigative genetic genealogy match rate estimated from a nation-wide population register
Forensic investigative genetic genealogy (FIGG) is a revolutionary method in forensic genetics, whereby genetic relatives of an unknown target person are detected in direct-to-consumer genomic databas...
www.biorxiv.org
August 12, 2026 at 8:18 PM
New preprint!
Investigative genetic genealogy has revolutionized forensic identification, with hundreds of cases solved to date.
But for any given new case, how likely is genetic genealogy to succeed?
We used a whole-country genealogy to find out!
1/10
www.biorxiv.org/content/10.6...
Investigative genetic genealogy has revolutionized forensic identification, with hundreds of cases solved to date.
But for any given new case, how likely is genetic genealogy to succeed?
We used a whole-country genealogy to find out!
1/10
www.biorxiv.org/content/10.6...
Reposted by Debbie Kennett 🧬🌳
'Genealogy Methods and Techniques' is now available to buy in the UK and will shortly be available on Kindle too. Want to know more? I've recorded a short video outlining some of the content and what my aims are with my publication.
youtu.be/Y0nM0kEwrnA
#Genealogy #ResearchMethods #NewBook
youtu.be/Y0nM0kEwrnA
#Genealogy #ResearchMethods #NewBook
Genealogy Methods and Techniques: an Introduction to My New Book
YouTube video by Dr Karen Cummings Genealogist
youtu.be
March 31, 2026 at 7:18 PM
'Genealogy Methods and Techniques' is now available to buy in the UK and will shortly be available on Kindle too. Want to know more? I've recorded a short video outlining some of the content and what my aims are with my publication.
youtu.be/Y0nM0kEwrnA
#Genealogy #ResearchMethods #NewBook
youtu.be/Y0nM0kEwrnA
#Genealogy #ResearchMethods #NewBook
Reposted by Debbie Kennett 🧬🌳
Do take a look at the webinar list, filled with talks from great names including @genealcymru.bsky.social @janetfew.bsky.social @nathandylangoodwin.bsky.social @debbiekennett.bsky.social @davelifelines.bsky.social @dnapainter.bsky.social @scientistsoph.bsky.social @andrewredfern.bsky.social and more
In celebration of our 21st Birthday, we are hosting an exciting week of webinars, talks from our tutors and friends of Pharos Tutors, old and new, Monday to Friday, starting 13th July 2026: www.pharostutors.com/webinars
March 30, 2026 at 12:50 PM
Do take a look at the webinar list, filled with talks from great names including @genealcymru.bsky.social @janetfew.bsky.social @nathandylangoodwin.bsky.social @debbiekennett.bsky.social @davelifelines.bsky.social @dnapainter.bsky.social @scientistsoph.bsky.social @andrewredfern.bsky.social and more
Reposted by Debbie Kennett 🧬🌳
Chris Fitzpatrick: Lucy Letby case should be a warning to other maternity hospitals
Chris Fitzpatrick: Lucy Letby case should be a warning to other maternity hospitals
If Letby’s conviction is unsafe, what alternative explanation might there be for the deaths of seven babies?
www.irishtimes.com
February 11, 2026 at 6:41 AM
Chris Fitzpatrick: Lucy Letby case should be a warning to other maternity hospitals
Reposted by Debbie Kennett 🧬🌳
Improved surname tool at John Grenham's Irish ancestors site! ☘️ #genealogy
www.johngrenham.com/blog/2026/01...
www.johngrenham.com/blog/2026/01...
A second chance with a second surname – John Grenham – Irish Roots
www.johngrenham.com
January 9, 2026 at 2:07 PM
Improved surname tool at John Grenham's Irish ancestors site! ☘️ #genealogy
www.johngrenham.com/blog/2026/01...
www.johngrenham.com/blog/2026/01...
Reposted by Debbie Kennett 🧬🌳
Join us in London on 8 Jan—open to 7pm with a complimentary drinks reception. Join us for Getting the Most from AI, our Hampshire research session + library tour, and browse special Hampshire materials. 🍷📚
Plus: FamilySearch Workshop on 9 Jan.
Book: sog.org.uk/events
Plus: FamilySearch Workshop on 9 Jan.
Book: sog.org.uk/events
December 14, 2025 at 12:00 PM
Join us in London on 8 Jan—open to 7pm with a complimentary drinks reception. Join us for Getting the Most from AI, our Hampshire research session + library tour, and browse special Hampshire materials. 🍷📚
Plus: FamilySearch Workshop on 9 Jan.
Book: sog.org.uk/events
Plus: FamilySearch Workshop on 9 Jan.
Book: sog.org.uk/events
Reposted by Debbie Kennett 🧬🌳
Begin your genealogy journey with Family History Skills – Stage 1 (13 Jan–31 Mar, online). Learn key records, evidence skills and tree-building with expert tutors.
Book by 31 Dec for the 2025 price + 20% off Stages 2 & 3. 📚✨
portal.sog.org.uk/Event/view/1...
Book by 31 Dec for the 2025 price + 20% off Stages 2 & 3. 📚✨
portal.sog.org.uk/Event/view/1...
December 15, 2025 at 12:01 PM
Begin your genealogy journey with Family History Skills – Stage 1 (13 Jan–31 Mar, online). Learn key records, evidence skills and tree-building with expert tutors.
Book by 31 Dec for the 2025 price + 20% off Stages 2 & 3. 📚✨
portal.sog.org.uk/Event/view/1...
Book by 31 Dec for the 2025 price + 20% off Stages 2 & 3. 📚✨
portal.sog.org.uk/Event/view/1...
Reposted by Debbie Kennett 🧬🌳
Where will your family history take you in 2026?
🔍 Family History Skills
🧬 Advanced DNA
⚖️ Crime & Punishment
Expert-led, online, recorded.
Book by 31 Dec to secure extended offers: portal.sog.org.uk/event/list
🔍 Family History Skills
🧬 Advanced DNA
⚖️ Crime & Punishment
Expert-led, online, recorded.
Book by 31 Dec to secure extended offers: portal.sog.org.uk/event/list
December 16, 2025 at 2:51 PM
Where will your family history take you in 2026?
🔍 Family History Skills
🧬 Advanced DNA
⚖️ Crime & Punishment
Expert-led, online, recorded.
Book by 31 Dec to secure extended offers: portal.sog.org.uk/event/list
🔍 Family History Skills
🧬 Advanced DNA
⚖️ Crime & Punishment
Expert-led, online, recorded.
Book by 31 Dec to secure extended offers: portal.sog.org.uk/event/list
A blog post from Ancestry clarifying that their services should not be used for law enforcement investigations.
www.ancestry.com/corporate/bl...
www.ancestry.com/corporate/bl...
December 12, 2025 at 12:12 AM
A blog post from Ancestry clarifying that their services should not be used for law enforcement investigations.
www.ancestry.com/corporate/bl...
www.ancestry.com/corporate/bl...
Reposted by Debbie Kennett 🧬🌳
The final speaker of session 5 is Debbie Kennett, Genetic Genealogist and Honorary Research Associate at University College London. Author of the books DNA and Social Networking and The Surnames Handbook, and contributor to the book Advanced Genetic Genealogy.
#PETconf25
#PETconf25
December 10, 2025 at 4:15 PM
The final speaker of session 5 is Debbie Kennett, Genetic Genealogist and Honorary Research Associate at University College London. Author of the books DNA and Social Networking and The Surnames Handbook, and contributor to the book Advanced Genetic Genealogy.
#PETconf25
#PETconf25
Reposted by Debbie Kennett 🧬🌳
Debbie’s presentation is entitled Does Consumer DNA Testing Spell the End of Donor Anonymity?
#PETconf25
#PETconf25
December 10, 2025 at 4:17 PM
Debbie’s presentation is entitled Does Consumer DNA Testing Spell the End of Donor Anonymity?
#PETconf25
#PETconf25
Reposted by Debbie Kennett 🧬🌳
Thank you Debbie for a really enjoyable and informative presentation. This will definitely have got people talking about the issues you raised. A great summary 'DNA = Donors are Not Anonymous'
#PETconf25
#PETconf25
December 10, 2025 at 4:28 PM
Thank you Debbie for a really enjoyable and informative presentation. This will definitely have got people talking about the issues you raised. A great summary 'DNA = Donors are Not Anonymous'
#PETconf25
#PETconf25
The beautiful, brave and heartfelt speech given by Lucy Letby's loyal friend Dawn at the recent Manchester conference "From flawed beginnings to broken lives" hosted by the Manchester Innocence Project and Nineteen Nurses. youtu.be/MAqwMDGiDkQ?... #LucyLetby
Dawn - My Friend is innocent - The Real Lucy Letby
YouTube video by Nineteen_Nurses
youtu.be
December 2, 2025 at 12:07 PM
The beautiful, brave and heartfelt speech given by Lucy Letby's loyal friend Dawn at the recent Manchester conference "From flawed beginnings to broken lives" hosted by the Manchester Innocence Project and Nineteen Nurses. youtu.be/MAqwMDGiDkQ?... #LucyLetby
Reposted by Debbie Kennett 🧬🌳
➡️ ALL parts of our special report into the Lucy Letby case are now available online: www.private-eye.co.uk/special-repo...
🧵3/3
🧵3/3
Special Report: The Lessons of the Lucy Letby Case
After Lucy Letby was convicted in August 2023 of murdering seven babies, a number of experts contacted Eye columnist MD because they
www.private-eye.co.uk
November 27, 2025 at 2:58 PM
➡️ ALL parts of our special report into the Lucy Letby case are now available online: www.private-eye.co.uk/special-repo...
🧵3/3
🧵3/3
Reposted by Debbie Kennett 🧬🌳
Right. Hitler's DNA. Brace yourselves for a deluge of misinformation and bad science.
I'm in Australia, so do get in touch if you want some expert debunking.
I'm in Australia, so do get in touch if you want some expert debunking.
November 13, 2025 at 6:37 AM
Right. Hitler's DNA. Brace yourselves for a deluge of misinformation and bad science.
I'm in Australia, so do get in touch if you want some expert debunking.
I'm in Australia, so do get in touch if you want some expert debunking.