Grace: Genetic engineers need to understand
all the regions of a gene in order
to make sure that it works properly.
So here, we'll be learning about the different regions
of a gene and how you can change them
to get them to do what you need.
So every cell has thousands upon thousands of genes,
and each of these genes has three distinct regions.
And so the first one is the promoter,
and the second one we'll focus on is the coding region.
So the promoter is like the on/off switch of a gene.
It determines where the gene is turned on
and copies of it are made.
So if it's a strong promoter, it'll make lots of copies.
If it's a weak promoter, it won't make very many copies.
And the other thing about promoters
is they're very specific to certain areas.
So there are some promoters
that only turn on genes in green tissue.
There are some promoters that only turn on genes
in the water uptake systems.
So by choosing a different promoter, you can change how
and where the gene is expressed.
So then the second region is the coding region,
and this what's actually copied,
to then go to make a protein.
And the protein is what gives the trait.
So this coding region is actually, it codes for a trait.
So now let's take a moment to think about
what the promoter was from
and what the coding region was from in Madan's story.
So we wanted the gene to be turned on in the roots
of the soybean because that's where the pathogen infects.
So where do you think we got the promoter from?
From soybeans, yes, so we got a root-specific promoter.
And then we wanted resistance to the SDS pathogen,
and Madan had found an Arabidopsis plant
that naturally had resistance.
So that was the source of our coding region.
He was then able to stitch these two regions together
to make the transgene, and so this is what was used
in his process.
So these are the typical first steps of a genetic engineer
as they are trying to make a transgene.
They first need to identify a promoter
and the proper coding region, put them together,
before they can ever be introduced into the plant
that you'd like to have the trait in the end.
The last region that we can mention
is the termination sequence,
and this determines where
the gene finishes copying.
So this is the end of the gene.
So knowing these regions is essential
to be a genetic engineer.
You need to know how to pick out the correct regions.
That way, when you put the right promoter
with the right coding region,
you can get the end result that you're looking for.