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Debbie Kennett 🧬🌳

@debbiekennett.bsky.social
883 followers 1K following 129 posts

DNA, genetic genealogy, family history. forensics. Honorary Research Fellow at UCL. All views my own.

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Reposted by Debbie Kennett 🧬🌳
Shai Carmi @shaicarmi.bsky.social · 12/08/2026
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.
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Reposted by Debbie Kennett 🧬🌳
Shai Carmi @shaicarmi.bsky.social · 12/08/2026
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
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Shai Carmi @shaicarmi.bsky.social · 12/08/2026
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
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Shai Carmi @shaicarmi.bsky.social · 12/08/2026
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
The probability of detecting multiple relatives of the target in the database. (A) The match rate when requiring at least two relatives in the database. All parameters are as in Figure 2. (B) The distribution of the number of relatives in the database. We only considered target individuals (alive or deceased) who have at least one relative in the database. The database size was 1% of the population (alive and >18) and we considered all 7th-degree or closer relatives. Target individuals already in the database count themselves towards the total number of relatives that they have there.
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Reposted by Debbie Kennett 🧬🌳
Shai Carmi @shaicarmi.bsky.social · 12/08/2026
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
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Shai Carmi @shaicarmi.bsky.social · 12/08/2026
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 FIGG match rate using a national population register. We plot the proportion of the Israeli population (including deceased) who have at least one relative in the genomic database to whom they connect via a path in the population register of a maximal pre-defined length. The x-axis is the database size, in proportion of the living population over 18 years old. Each curve (legend) corresponds to a different maximal degree of relationship. For example, a first-degree relative is a parent or a full sibling, and a second-degree relative can be a half-sibling, a grandparent, or an aunt. Each data point is the average over 100 simulations. Standard deviations across simulations are shown as error bars, but are too small to be visible.
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Shai Carmi @shaicarmi.bsky.social · 12/08/2026
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
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Reposted by Debbie Kennett 🧬🌳
Shai Carmi @shaicarmi.bsky.social · 12/08/2026
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
Characteristics of the IPIA data. (A) The distribution of birth decades (1870s-2010s). (B) The average number of children per individual (including childless individuals or individuals who have not yet completed their families) vs the parental birth decade. Birth decades start at the indicated year (e.g., the 1960 birth decade corresponds to birth years 1960-1969). (C) The distribution of the number of children per individual. We combined all individuals with 15 or more children into a single category (see also Figure S1). The y-axis is logarithmic. (D) The distribution of the paternal (light blue) and maternal age (pink) at childbirth, also known as the generation interval. The distribution is over all births in the database. Numbers on the x-axis indicate the midpoints of 3-year bins (e.g., 25 corresponds to ages 24-26).
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Reposted by Debbie Kennett 🧬🌳
Shai Carmi @shaicarmi.bsky.social · 12/08/2026
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
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Shai Carmi @shaicarmi.bsky.social · 12/08/2026
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
A schematic of FIGG. For a subset of the population, a genome-wide DNA profile is available in a “genomic database” (light blue box). The identity of a target person (peach box) is unknown, but we have access to their genome-wide genetic profile. By comparing the DNA profile of the target against that of all individuals in the database, genetic relatives of the target (“matches”; red arrows) can be identified (light green box inside the database). Once matches have been detected, the investigation focuses on their relatives (green and red arrows), given that the target person must be one of them. Thus, to be identifiable using FIGG, a target person must have at least one relative in the database. We require the relationship to be equal or closer to a prespecified degree, corresponding to the most distant relationship that can be confidently detected using genetic data (usually 7th degree, e.g., a third cousin). In practice, more distant relationships can also sometimes be detected.
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Shai Carmi @shaicarmi.bsky.social · 12/08/2026
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...
biorxiv.org
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...
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Reposted by Debbie Kennett 🧬🌳
Karen Cummings @drkarencummings.bsky.social · 31/03/2026
'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
Genealogy Methods and Techniques: an Introduction to My New Book
YouTube video by Dr Karen Cummings Genealogist
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Karen Cummings @drkarencummings.bsky.social · 30/03/2026
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
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The Irish Times @irishtimes.com · 11/02/2026
Chris Fitzpatrick: Lucy Letby case should be a warning to other maternity hospitals
irishtimes.com
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?
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Megan Smolenyak @megansmolenyak.com · 09/01/2026
Improved surname tool at John Grenham's Irish ancestors site! ☘️ #genealogy www.johngrenham.com/blog/2026/01...
johngrenham.com
A second chance with a second surname – John Grenham – Irish Roots
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Society of Genealogists @sogorg.bsky.social · 14/12/2025
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
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Society of Genealogists @sogorg.bsky.social · 15/12/2025
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...
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Society of Genealogists @sogorg.bsky.social · 16/12/2025
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
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Debbie Kennett 🧬🌳 @debbiekennett.bsky.social · 12/12/2025
A blog post from Ancestry clarifying that their services should not be used for law enforcement investigations. www.ancestry.com/corporate/bl...
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Progress Educational Trust (PET) @pet-bionews.bsky.social · 10/12/2025
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
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Reposted by Debbie Kennett 🧬🌳
Progress Educational Trust (PET) @pet-bionews.bsky.social · 10/12/2025
Debbie’s presentation is entitled Does Consumer DNA Testing Spell the End of Donor Anonymity? #PETconf25
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Reposted by Debbie Kennett 🧬🌳
Progress Educational Trust (PET) @pet-bionews.bsky.social · 10/12/2025
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
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Debbie Kennett 🧬🌳 @debbiekennett.bsky.social · 02/12/2025
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
youtu.be
Dawn - My Friend is innocent - The Real Lucy Letby
YouTube video by Nineteen_Nurses
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Reposted by Debbie Kennett 🧬🌳
Private Eye Magazine @privateeyenews.bsky.social · 27/11/2025
➡️ ALL parts of our special report into the Lucy Letby case are now available online: www.private-eye.co.uk/special-repo... 🧵3/3
private-eye.co.uk
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
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Reposted by Debbie Kennett 🧬🌳
Adam Rutherford @adamrutherford.bsky.social · 13/11/2025
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.
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Reposted by Debbie Kennett 🧬🌳
Private Eye Magazine @privateeyenews.bsky.social · 12/11/2025
MD's latest on the Lucy Letby case, only in the new Private Eye, out now. ➡️ Read all previous parts of our special report into the Lucy Letby case online: www.private-eye.co.uk/special-repo... 🧵3/3
private-eye.co.uk
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
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Reposted by Debbie Kennett 🧬🌳
Bailiwick Express @bailiwickexpress.bsky.social · 18/11/2025
Members of two local families have publicly raised their concerns about consultant paediatrician and expert witness Dr Sandie Bohin, whose heped prosecute Lucy Letby. They spoke at a conference focused on the convicted murderer's case and calls for a review of the evidence on Saturday.
bailiwickexpress.com
Guernsey families publicly cast doubt over key expert witness in Letby prosecution
Members of two local families have publicly raised their concerns about consultant paediatrician and expert witness Dr Sandie Bohin, whose testimony was used to prosecute Lucy Letby. They spoke at a conference focused on the convicted murderer's case and calls for a review of the evidence on Saturday. The individuals, who wish to remain anonymous, delivered presentations outlining their ordeals in trying to secure correct diagnoses and treatments for their ill children across multiple encounters with Dr Bohin.
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Society of Genealogists @sogorg.bsky.social · 15/11/2025
Advance your DNA skills in 2026. Join leading experts @miagen.bsky.social @debbiekennett.bsky.social @genealogylass.bsky.social @scientistsoph.bsky.social & @donnasr.bsky.social for a 12-week online course in advanced genetic genealogy. 📅 5 Jan – 25 Mar 2026 👉
portal.sog.org.uk
Advancing your DNA Skills
12 week course on Wednesday and Monday evenings
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Reposted by Debbie Kennett 🧬🌳
Dr Carole McCartney 🏳️‍🌈 🏳️‍⚧️ @ctmccartney.bsky.social · 29/10/2025
www.theguardian.com/news/audio/2...
theguardian.com
From the archive: The queen of crime-solving – podcast
This week, from 2022: forensic scientist Angela Gallop has helped to crack many of the UK’s most notorious murder cases. But today she fears the whole field – and justice itself – is at riskBy Imogen ...
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Reposted by Debbie Kennett 🧬🌳
Jackie Depelle @jackiedepelle.bsky.social · 19/10/2025
The #GuildOneName Studies hosted an inspiring #DNA seminar in Leicester October 2026. The recordings of the talks are now available in the Members' Room. Enjoy! (Note not all talks were recorded.) one-name.org/seminar-even...
one-name.org
Seminar events
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Debbie Kennett 🧬🌳 @debbiekennett.bsky.social · 19/10/2025
There's now a blog post from @myheritageofficial.bsky.social with further details about the transition to whole genome sequencing. blog.myheritage.com/2025/10/myhe...
blog.myheritage.com
MyHeritage Upgrades Its DNA Tests to Whole Genome Sequencing - MyHeritage Blog
The MyHeritage DNA test has been upgraded to use Whole Genome Sequencing, the most comprehensive method for reading DNA available today.
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Debbie Kennett 🧬🌳 @debbiekennett.bsky.social · 14/10/2025
A big announcement today from @myheritageofficial.bsky.social. They are transitioning to low-coverage whole-genome sequencing for their direct-to-consumer DNA test heralding a new era for genetic genealogy. cruwys.blogspot.com/2025/10/myhe...
cruwys.blogspot.com
MyHeritage upgrades its consumer DNA test to whole-genome sequencing
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Society of Genealogists @sogorg.bsky.social · 10/10/2025
🎉 Congrats to @debbiekennett.bsky.social, F.S.G.! Our CEO Philip Spedding, presented Debbie with her Fellowship certificate for distinguished services to genealogy during her recent DNA talk at the Society. 📸 Thanks to volunteer photographer Grant White for capturing the moment! #Genealogy
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Society of Genealogists @sogorg.bsky.social · 18/09/2025
#GenHour 🧬 Got a tricky DNA question? Join @DebbieKennett at our DNA Advice Hour – exclusive to Gold Members. 📅 Fri 26 Sept | 14:00 BST | Online 👉 Submit your questions by 23 Sept! 🔗 portal.sog.org.uk/Ev... #Genealogy #DNA
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Debbie Kennett 🧬🌳 @debbiekennett.bsky.social · 22/08/2025
An outstanding, empathetic long-read article on the tragic case of Constance Marten and Mark Gordon. Like the writer I've always wondered why this couple were prosecuted and brought to trial in the first place. Parents who lose a child deserve compassion not punishment. www.lrb.co.uk/the-paper/v4...
lrb.co.uk
Clair Wills · The Price of Safety: Constance Marten’s Defiance
The trials of Constance Marten and Mark Gordon were held to determine their criminal responsibility for their daughter...
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Debbie Kennett 🧬🌳 @debbiekennett.bsky.social · 13/08/2025
A very interesting interview with Anouk Curry, the producer of the recent highly acclaimed ITV documentary on the Lucy Letby case. youtu.be/xDu0nYfZKz4?... #LucyLetby
youtu.be
Lucy Letby documentary producer: the alternative theories and what happens next | The Daily T
YouTube video by The Telegraph
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Ian Dunt @iandunt.bsky.social · 04/08/2025
The ITV documentary about Lucy Letby is very good. Old school, public interest broadcasting which assumes the intelligence and the conscience of its audience. Anyone with the slightest interest in the case should watch it.
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Private Eye Magazine @privateeyenews.bsky.social · 06/08/2025
➡️ Read all previous parts of our special report into the Lucy Letby case online: www.private-eye.co.uk/special-repo...
private-eye.co.uk
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
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Debbie Kennett 🧬🌳 @debbiekennett.bsky.social · 11/08/2025
This is an excellent briefing paper on the junk science and shoddy statistics used in the Lucy Letby case. It is written by 18 experts, some of whom have not spoken out before. The paper was first published on 1 May 2025. www.dropbox.com/scl/fi/bxrjy...
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Dr Elisa Perego @elisaperego78.bsky.social · 09/08/2025
Key genetic differences involved in the immune and nervous systems have been found in people with ME/CFS www.newscientist.com/article/2491...
newscientist.com
Key genetic differences found in people with chronic fatigue syndrome
People with chronic fatigue syndrome, also known as myalgic encephalomyelitis, appear to have eight genetic signals that differ from those without the condition
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Debbie Kennett 🧬🌳 @debbiekennett.bsky.social · 09/08/2025
A must-watch documentary from ITV on the Lucy Letby case (UK viewers only). This case will eventually be remembered as one of the worst miscarriages of justice in British history. youtu.be/UohWz9L6PTs?...
youtu.be
Lucy Letby: Beyond Reasonable Doubt? | ITV
YouTube video by ITV Real Life Stories
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Private Eye Magazine @privateeyenews.bsky.social · 23/07/2025
Part 24 of our Special Report into the Lucy Letby case is now available to download from the Eye website here: private-eye.co.uk/special-repo... Part 25 by Dr Phil Hammond is also available to read in the brand new issue of Private Eye which is out now.
private-eye.co.uk
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
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Society of Genealogists @sogorg.bsky.social · 19/06/2025
Hi #GenHour! 🧬 Are you new to DNA testing? If so, @debbiekennett.bsky.social will guide you through autosomal DNA this Sat 21 June at 14:00. Understand cM, cousin matches, and what DNA can and can’t tell you. Register: portal.sog.org.uk/Ev... #GeneticGenealogy #FamilyHistory
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Who Do You Think You Are? Magazine @wdytyamagazine.bsky.social · 17/06/2025
Our latest issue is on sale now! This month, @debbiekennett.bsky.social looks at how AI is transforming family history. Plus, what first names tell us about family history, the history of the first motor cars, researching the Irish Famine, and much more: www.whodoyouthinkyouaremaga...
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Dr Carole McCartney 🏳️‍🌈 🏳️‍⚧️ @ctmccartney.bsky.social · 09/06/2025
insidetime.org/newsround/fo...
insidetime.org
Forensic science is “in a graveyard spiral” leading to miscarriages of justice
A failing forensic science system has caused major miscarriages of justice, a three-year Parliamentary inquiry has found. The investigation into forensics, launched by the All-Party Parliamentary G…
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ABC News Bot (unofficial) @abcnewsbot.bsky.social · 07/06/2025
Lucy Letby is currently serving multiple life sentences after being convicted of murdering seven babies and attempting to kill others. There's only one problem: the group of experts saying there's no evidence of wrongdoing.
abc.net.au
Three lessons from the case of convicted baby killer Lucy Letby
Lucy Letby is currently serving multiple life sentences after being convicted of murdering seven babies and attempting to kill others. There's only one problem: the group of experts saying there's no evidence of wrongdoing.
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The Francis Crick Institute @crick.ac.uk · 02/05/2025
Watch ‘Falsely Accused: Justice by Genomics’ held at the Crick this week, with experts in science, medicine and the law discussing the case of Kathleen Folbigg and the role of genomic investigation in unexplained child deaths. Catch up on all the expert talks: www.crick.ac.uk/news/2025-04...
crick.ac.uk
“Science uncovered the truth of why my children died, and set me free”
After twenty years in jail, convicted of killing her four children, Kathleen Folbigg is sharing her experience of being falsely accused alongside the team of scientists and lawyers who used advances i...
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Debbie Kennett 🧬🌳 @debbiekennett.bsky.social · 01/05/2025
I'm going to be at the Family History Show at Aintree Racecourse on Saturday talking about getting the most out of your DNA matches and helping out on the Ask the Experts table. thefamilyhistoryshow.com/liverpool/
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Guy Rowland @guyrowlanduk.bsky.social · 09/04/2025
A new short film from me - Lucy Letby and the Witch Hunt Machine. The official inquiry into Lucy Letby was set up to learn lessons. Is it looking in the right places? Contains new interviews with @gill1109.bsky.social and Private Eye's MD Phil Hammond. youtu.be/nNl1kNysKgw
youtu.be
Lucy Letby and the Witch Hunt Machine
YouTube video by Lucy Letby Films
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Abdel Abdellaoui @dr-appie.bsky.social · 28/03/2025
"I wanted to have that be clear — that he’s not on my team and I’m not on his" - me on Emil Kirkegaard in this great piece from @undark.org: undark.org/2025/03/26/u...
undark.org
In Genetics, a Tense Coexistence of Mainstream and Fringe Views
In an era of open data, genome-wide association studies have become entangled with efforts to prove Black inferiority.
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