A number of Quebecois commentators on this video were a tad upset. Been investigating...
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Copilot:
Genetic analysis; in studying a genome, is there any way to determine how long this form of the gene has been appearing. I am assuming not!
Short answer: Yes — you can estimate how long a particular gene variant has been around, and modern population‑genomic methods do this surprisingly well. It’s not perfect, but it’s absolutely possible.
🧬 Core idea: You can date a gene variant by reconstructing its ancestry
Researchers estimate the age of a mutation (i.e., when the allele first appeared) by looking at:
Shared haplotypes around the mutation
Patterns of recombination that have broken down those haplotypes over generations
Mutation clocks (how many new mutations have accumulated nearby)
Coalescent-based models that infer how far back the carriers share a common ancestor
This is exactly what methods like GEVA (Genealogical Estimation of Variant Age) do. They combine mutation and recombination signals to estimate when the allele first arose.
🧬 What the research shows
A 2020 study estimated the ages of 45 million human SNPs, showing that many common variants are thousands of generations old.
These methods don’t require detailed demographic models and can work across huge datasets.
Age estimates come with uncertainty, but they’re robust enough to build resources like the Atlas of Variant Age.
More recent work extends this to structured populations, jointly estimating both the time and population of origin of a mutation.
🧬 What you can determine
You can estimate:
When the mutation first appeared (e.g., 5,000 years ago, 150 generations ago)
Whether it’s ancient or recent
Whether it arose once or multiple times
Which population it likely originated in
These are not guesses — they’re statistical estimates grounded in real genomic patterns.
🧬 What you cannot determine
You cannot determine:
The exact individual in whom the mutation first appeared
The precise date (you get a credible interval, not a timestamp)
The age of a gene form if recombination or recurrent mutation has scrambled the signal too much
The age of extremely rare variants with very few carriers (data too sparse)
So your intuition (“I am assuming not!”) is understandable — but modern methods have pushed far beyond what was possible even 10 years ago.
🧬 Why this works at all
Every mutation starts on a specific chromosome. Over generations:
Recombination chops up the surrounding DNA
New mutations accumulate nearby
Lineages coalesce back to a shared ancestor
By measuring how much “breakdown” has occurred, you can infer how long the allele has been around.
Think of it like dating a fossil by the layers around it — except the layers are recombination events and mutation counts.
🧬 If you want, I can explain:
How GEVA works step‑by‑step
How accurate these estimates are
How scientists date specific famous variants (e.g., lactase persistence, skin pigmentation genes)
What this means for human evolution and ancestry
Would you like a deeper dive into the methodology or examples?
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