All language subtitles for 57031x_MH_Overview_05_Key_Definitions_v1-en

MICHAEL HEMANN: So we'll just end

with a few basic definitions to move forward.

So we'll talk a lot about alleles.

An allele is a version of a gene, right?

We're diploid, so we have two copies

of just about every gene.

So we have two alleles.

Sometimes they are the same.

Sometimes they're different.

And then there are mutants.

And so a mutant is an altered version of a gene.

But importantly, it is a change that we witness,

meaning that we see it happen.

So if we don't see it happen, we don't

know where it originated-- it could be

just a variant in a population.

So we don't refer to mutations in people in general,

unless we actually see it happening for the first time.

This is the first person where the parents didn't have this

and there's a mutation that occurred in the germline

that we observed.

So the new COVID variants are COVID mutants

because they came from a strain that

did not have this alteration.

So these are new.

They emerged in a population where they didn't exist before.

They're an alteration that we observe.

So a genotype are--

is essentially all of the alleles of an individual.

And then finally, this term wildtype.

So a wildtype refers to a defined standard genome.

So all of the strains that we talk about

are generally highly inbred.

They have two identical copies of the same allele

if they're diploid.

If not, like yeast-- we'll talk about next time--

they're haploid, and we just use them as a reference

so we can see mutations.

Wildtype just allows us to say we saw this change occur.

Wildtype does not mean healthy.

So there are wild-type mice that we

have in our colony that would not survive in the wild.

There are wild-type yeasts that wouldn't be able to compete

with other yeasts probably in the wild,

but there's just they're just a reference genome--

a reference strain that we talk about just for convention.

And really importantly, we generally don't say wild type

and we never say wild type when it refers to people.

There are no wild type people.

So there's just variation in our--

between us in regards to a diverse set

of genes and characteristics.

But there is no normal in any of us, right?

So that will become important, I think,

as we think about diversity and we think about context.

And so next time, we're going to Talk

about more of what we can know about a gene

with actually knowing-- out knowing any of the sequence.

So we're going to start thinking about the gene as a functional

unit, and all of the, I think, really cool things

we can learn just by starting to do some crosses.