So today we're going to do something a little bit
So today we're going to do something a little bit

different.
different.

We have a special guest, and we're
We have a special guest, and we're

going to talk about a fascinating interplay
going to talk about a fascinating interplay

between your genes and your environment-- freckles.
between your genes and your environment-- freckles.

So my name's Alex Dainis, and I'm a genetics PhD student.
So my name's Alex Dainis, and I'm a genetics PhD student.

And my name is Trina Espinosa, a.k.a.
And my name is Trina Espinosa, a.k.a.

MsBeautyphile, and I like to talk about the science
MsBeautyphile, and I like to talk about the science

behind beauty.
behind beauty.

[MUSIC PLAYING]
[MUSIC PLAYING]

I have freckles.
I have freckles.

And I don't, which is a total bummer,
And I don't, which is a total bummer,

because right now, freckles are totally trending in beauty.
because right now, freckles are totally trending in beauty.

While trends of earlier decades favored covering up
While trends of earlier decades favored covering up

those freckles with heavy makeup,
those freckles with heavy makeup,

more recent beauty trends are encouraging
more recent beauty trends are encouraging

us to play our freckles, which are
us to play our freckles, which are

thought to be more youthful and natural in appearance.
thought to be more youthful and natural in appearance.

Earlier this year, I saw lots of beauty tutorials
Earlier this year, I saw lots of beauty tutorials

that use eyeliner to dot a few extras across your face.
that use eyeliner to dot a few extras across your face.

Or Instagram hashtags that showed serious beauty devotees
Or Instagram hashtags that showed serious beauty devotees

going as far as having freckles tattooed across their face.
going as far as having freckles tattooed across their face.

So that has me posing the question,
So that has me posing the question,

what is a freckle, Alex?
what is a freckle, Alex?

Yeah, so people use the word freckle
Yeah, so people use the word freckle

to refer to two different things.
to refer to two different things.

So the first are ephelides.
So the first are ephelides.

So these are the freckles we generally think of in children.
So these are the freckles we generally think of in children.

They're small reddish-brown freckles
They're small reddish-brown freckles

that appear in the spring and summer on your face, back,
that appear in the spring and summer on your face, back,

and arms.
and arms.

So areas that are exposed to the sun.
So areas that are exposed to the sun.

But sometimes people also use the word "freckle"
But sometimes people also use the word "freckle"

to refer to lentigines.
to refer to lentigines.

So these are darker spots that appear with age,
So these are darker spots that appear with age,

that don't really change with the seasons,
that don't really change with the seasons,

and that occur after years of sun damage.
and that occur after years of sun damage.

OK.
OK.

So those are like age spots.
So those are like age spots.

Yeah.
Yeah.

So today, when we talk about the word "freckle"
So today, when we talk about the word "freckle"

we're going to talk about ephelides.
we're going to talk about ephelides.

But I think, before we do that, we
But I think, before we do that, we

need to put some freckles on our face!
need to put some freckles on our face!

Totally!
Totally!

OK, ready?
OK, ready?

Here we go.
Here we go.

Yeah.
Yeah.

[DISTORTED FAST FORWARD SOUND EFFECT]
[DISTORTED FAST FORWARD SOUND EFFECT]

What do you think?
What do you think?

So let's talk about what makes a real freckle?
So let's talk about what makes a real freckle?

A real freckle is caused by melanin.
A real freckle is caused by melanin.

That is a pigment that gives hair and skin its color.
That is a pigment that gives hair and skin its color.

A freckle forms on the skin when a cell called
A freckle forms on the skin when a cell called

a melanocyte overproduces melanin in response
a melanocyte overproduces melanin in response

to UV radiation from the sun.
to UV radiation from the sun.

The melanin is packaged into melanosomes,
The melanin is packaged into melanosomes,

and melanocytes inject them into skin cells
and melanocytes inject them into skin cells

as they migrate towards the upper layers of skin.
as they migrate towards the upper layers of skin.

When this happens in a concentrated area,
When this happens in a concentrated area,

it is called a freckle.
it is called a freckle.

But not everybody has them.
But not everybody has them.

So is that a genetics thing?
So is that a genetics thing?

It is.
It is.

So some people are more prone to getting freckles than others.
So some people are more prone to getting freckles than others.

And this can totally be traced back to your genetics,
And this can totally be traced back to your genetics,

meaning that it can also be inherited and passed down
meaning that it can also be inherited and passed down

through families.
through families.

OK.
OK.

So while there are genes that make
So while there are genes that make

you more susceptible to getting freckles,
you more susceptible to getting freckles,

you also need that UVA light exposure
you also need that UVA light exposure

to actually have them happen.
to actually have them happen.

This is why we think about them in the spring and summer, when
This is why we think about them in the spring and summer, when

kids are outside playing in the sun.
kids are outside playing in the sun.

Exactly.
Exactly.

It's the environment and your genetics
It's the environment and your genetics

that creates a freckle.
that creates a freckle.

So how did researchers first figure out
So how did researchers first figure out

that this is a genetic trait?
that this is a genetic trait?

So I found this insane experiment from 1982,
So I found this insane experiment from 1982,

that I'd like to put into the category of "crazy things that
that I'd like to put into the category of "crazy things that

college students will do for science".
college students will do for science".

I think I've done some of those.
I think I've done some of those.

Yeah, me too.
Yeah, me too.

So the researchers took 18 18-to-23 year olds,
So the researchers took 18 18-to-23 year olds,

and they split them up into two groups of known frecklers
and they split them up into two groups of known frecklers

and known non-frecklers.
and known non-frecklers.

Hm.
Hm.

How did they make that determination?
How did they make that determination?

So the known freckles all had visible spots on them
So the known freckles all had visible spots on them

at the time, and a childhood history of freckling.
at the time, and a childhood history of freckling.

And the known non-frecklers had neither of those things.
And the known non-frecklers had neither of those things.

So the researchers took these two groups, and the exposed
So the researchers took these two groups, and the exposed

areas of their lower back-- which is generally
areas of their lower back-- which is generally

protected from the sun and has few freckles--
protected from the sun and has few freckles--

to intense amounts of UV light.
to intense amounts of UV light.

Yikes!
Yikes!

That sounds scary!
That sounds scary!

Yeah, it is scary.
Yeah, it is scary.

And I would totally not have wanted
And I would totally not have wanted

to be a subject in this study.
to be a subject in this study.

[LAUGHTER]
[LAUGHTER]

But what they found was that all of the known frecklers
But what they found was that all of the known frecklers

actually had freckles appear after this exposure,
actually had freckles appear after this exposure,

and none of the known non-frecklers did.
and none of the known non-frecklers did.

I see.
I see.

So they figured out that there was probably
So they figured out that there was probably

a genetic component to this.
a genetic component to this.

You had to be susceptible to it before the UV exposure
You had to be susceptible to it before the UV exposure

to actually get freckles.
to actually get freckles.

Let's cut to the nitty gritty.
Let's cut to the nitty gritty.

What genes are associated with freckling?
What genes are associated with freckling?

I hear there's like five.
I hear there's like five.

Yeah, so there are about five genes
Yeah, so there are about five genes

that have been associated with freckling at this point.
that have been associated with freckling at this point.

But the most well-studied, and probably the most impactful,
But the most well-studied, and probably the most impactful,

is a gene called MC1R, which codes
is a gene called MC1R, which codes

for a receptor on the surface of your melanocytes, those cells
for a receptor on the surface of your melanocytes, those cells

that make the melanin pigment.
that make the melanin pigment.

So it's the MC1R that determines the type of melanin
So it's the MC1R that determines the type of melanin

that our melanocytes make, whether that's the eumelanin--
that our melanocytes make, whether that's the eumelanin--

the brown black pigment--
the brown black pigment--

or pheomelanin-- the reddish pigment?
or pheomelanin-- the reddish pigment?

Exactly.
Exactly.

Hm.
Hm.

And so, when we think about our genes,
And so, when we think about our genes,

we have two copies of every gene-- one from our mother,
we have two copies of every gene-- one from our mother,

and one from our father.
and one from our father.

And these copies that we inherit can come in different versions,
And these copies that we inherit can come in different versions,

or alleles.
or alleles.

So this variation in the MC1R gene
So this variation in the MC1R gene

can determine whether or not it gives you
can determine whether or not it gives you

these darker pigments or lighter pigments,
these darker pigments or lighter pigments,

and these alleles have been associated with everything
and these alleles have been associated with everything

from red hair and pale skin, to freckles.
from red hair and pale skin, to freckles.

So while we can buy temporary or permanent freckle tattoos that
So while we can buy temporary or permanent freckle tattoos that

make us look more youthful and-- (BLOWS KISS) -- sunkissed,
make us look more youthful and-- (BLOWS KISS) -- sunkissed,

our real freckles are determined by our genes,
our real freckles are determined by our genes,

which are given to us by our parents.
which are given to us by our parents.

Or whether or not we slather on sunscreen
Or whether or not we slather on sunscreen

before we hit the pool.
before we hit the pool.

Exactly.
Exactly.

Thank you so much for answering all my freckle questions, Alex.
Thank you so much for answering all my freckle questions, Alex.

Well, thank you so much for being here.
Well, thank you so much for being here.

But now I think it's time that we take off of these freckles,
But now I think it's time that we take off of these freckles,

with--
with--

my summer water.
my summer water.

What?
What?

But what is my summer water?
But what is my summer water?

I'll tell you if you head on over to my channel.
I'll tell you if you head on over to my channel.

The link is right up here.
The link is right up here.

You can also go over and subscribe
You can also go over and subscribe

to MsBeautyphile's channel by clicking here,
to MsBeautyphile's channel by clicking here,

and subscribe to mine by clicking here.
and subscribe to mine by clicking here.

And as always, a huge shout out to my Patreon patrons
And as always, a huge shout out to my Patreon patrons

for making fun videos like this possible.
for making fun videos like this possible.

[MUSIC PLAYING]
[MUSIC PLAYING]