Name: 遺伝子の研究者だけど質問ある？ | Tech Support | WIRED Japan
Uploaded: 2025-02-08T09:41:05.000Z
Duration: 14 min 20 s
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I'm Dr. Neville Sanjana, human geneticist.

Today I'll be taking your questions from Twitter.

At sort of known oh asks, someone explain Lenny Kravitz to me, please.

I'd like to understand how his genes work.

I'm not sure there's a gene for hot, but most complex traits are not due to just one gene, they're due to many genes.

All of us inherit part of our genome from our mom and part of our genome from our dad.

And Lenny Kravitz has a pretty diverse ancestry.

He has Russian Jewish ancestry from his father's side.

He has Afro-Caribbean ancestry from his mother's side.

The genes that control our immune system are amongst the most variable genes in the human genome.

Maybe the secret to Lenny's youthfulness is that he inherited a diverse set of immune genes.

At no traffic in LA asks, can they DNA test ashes?

Unfortunately no, DNA breaks down at temperatures above 400 degrees Fahrenheit and cremation happens at very high temperatures like 1500 degrees or 2000 degrees Fahrenheit.

But at ambient temperature, the story is different.

In fact, the Nobel Prize in 2022 was given out to Svante Paabo for sequencing and reconstructing the genome of a Neanderthal.

At cissex serve asks, I personally find it hard to believe that all human beings who have blue eyes are descendants of one human being who had a genetic mutation.

All current evidence points to an event about 6,000 to 10,000 years ago that resulted in a mutation in a gene called OCA2.

OCA2 is responsible for a protein called melanin in our eyes.

That mutation occurred in Europe and all blue eyed people today are distantly related to that founder from 10,000 years ago.

But it's not the only gene that's important for eye color.

There are about eight genes that we know about that contribute to eye color in humans.

And even if you have the brown eyes version of OCA2, sometimes you can end up with blue eyes and that's due to the contributions from those seven other genes.

At van den Lebron asks, how does 23andMe work?

In fact, 23andMe does a lot of basic genetics research in addition to testing your DNA.

Here are two flow cells from an Illumina sequencer.

These can sequence hundreds of human genomes in a single day.

We flow in the DNA, it binds to this glass slide and then the sequencer acts like a very powerful microscope that can image the DNA, but sequencing costs a lot.

It can cost about $1,000 to sequence a whole human genome.

The secret is that they only sequence a small portion of the genome, maybe one 100th of 1% of the 6 billion bases of the human genome.

And even those half million bases can tell us a lot about ancestry and specific traits you might have.

So they compare your genome to people from Scotland or people from Brazil, and that's how they can tell what percent of you comes from here or what percent of you comes from there.

At Mother Nature God asks, but why do genes mutate at all?

Genes can recombine in ways that introduce genetic diversity.

Some mutations can give us stronger bones, they can protect against heart disease or protect against severe COVID.

If this diversity didn't happen at each generation, we'd be like bananas.

Modern bananas are all clones of each other.

80 years ago, all bananas were a different clone, the Gros Michel clone.

And then a fungal infection came and wiped out the entire population.

So now let's talk about the bad mutations.

The disease that comes to mind here is cancer.

Those are the mutations you're not born with, but that arise later in life.

They're acting out of line and start growing in ways that we don't expect and don't want.

At ShittyQuestions asks, how does sun affect your DNA?

UV can be a very, very powerful mutagen for DNA.

And what it does specifically is these C bases, these green bases, it can turn them into T bases, these red bases.

Now, if this happens, most of these mutations, they don't do anything.

But if it happens in certain genes that are important in cancer, like oncogenes or tumor suppressor genes, it can create deadly cancers like skin cancer.

At Michael Kai asks, God, why do my genes have to make me 5'1"?

Well, height is truly an amazing trait because it's super polygenic.

That means many, many different places in the genome contribute to height.

We think that we can explain about 50% of the contributions to height based on genes alone.

Well, that probably has something to do with the environment you grew up in, the foods you ate, things like that.

At EEE Lemons asks, guys, quick, how are DNA and genes related?

DNA is the letters that make up genes, A, T, C, and G.

When we arrange those letters in very specific ways, we can write longer words, and those words are the genes.

They're actually arranged like chapters in a book.

If chromosomes are like chapters in a book, the human genome is the whole book.

At Cosine Distance asks, Alexa, am I related to Genghis Khan?

There are estimates that one in 200 men living today carry a very similar Y chromosome, which indicates a recent common ancestor.

All men inherit the Y chromosome, not from mom and dad, but just from their dads.

And Genghis Khan, he lived about 800 years ago.

It's possible that about 0.5% of the men living today inherited their Y chromosome from a recent common ancestor, maybe Genghis Khan.

At Nino Clutch asks, Spider-Man is so raw.

Maybe we should try that DNA biotech cross-gene splicing.

Well, I'm not sure we're gonna see Spider-Man anytime soon, but there is a lot of interest from biotech companies and academic labs to understand spider silk, which is five times stronger than steel.

Spider silk is very biocompatible, very good for wound healing, especially for wounds of the eye and the brain.

And there's been many efforts to engineer spider silk outside of spiders, to make it in a recombinant way, meaning not in spiders, but in other organisms like bacteria or plants.

Probably the best known example of a recombinant protein is insulin.

This has helped millions of people across the last four decades since the first insulin was produced in bacteria.

At someonegoogled asks, how does CRISPR work step-by-step?

Well, CRISPR is not the thing in your fridge.

When we talk about CRISPR, especially in terms of medicine, we're normally talking about a protein called Cas9.

Cas9 comes from bacterial genomes, but we as genome engineers have taken it and repurposed it for uses in the lab and for genetic medicine.

The first step for CRISPR is to tell it where to go in the genome.

And the way that we program the common CRISPR enzyme, Cas9, is that we give it a little piece of RNA that matches the DNA in the genome.

And so Cas9 can surf along the genes, the DNA bases in the genome, until it finds the perfect match for its guide RNA.

Once it finds that match, then it knows where to make the cut.

And you can think of Cas9 like a pair of scissors.

It just snips at a specific location in the DNA.

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遺伝子の研究者だけど質問ある？ | Tech Support | WIRED Japan

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