The genetic path to biodiversity – Science Nation

The genetic path to biodiversity – Science Nation

Miles O’Brien: Feast your eyes on these
“Painted Ladies.” An apt name,
for a butterfly so vibrant. Arnaud Martin:
Butterflies and moths constitute 10% of all known biodiversity
in terms of numbers of species and they really display
in front of us a rich canvass of colors
and patterns on their wings. Miles O’Brien: With support from the National
Science Foundation, developmental biologist
Arnaud Martin and a team at George
Washington University are using cutting-edge genomic
techniques to better understand how the rich stripes
and swirls of a butterfly’s wing take their shape. Arnaud Marti:
The wing patterns are used in nature for camouflage, avoiding predators,
indicating toxicity and also to find mates. So, we know why they
are all so diverse, but now the question I would say
is to understand how it happens, how do you create such
an explosive diversity during deep evolutionary time. Miles O’Brien:
The team uses the genome editing tool called CRISPR, which cuts DNA
at targeted locations like a pair of
molecular scissors. Arnaud Martin:
The way we use CRISPR here in this lab is simply to make little snips
in the genome to modify genes. And, then we see
what is going wrong during butterfly development and it’s sometimes translated into some modification of the wing patterns. Miles O’Brien:
They start by gathering eggs – these little blue spheres. Once they get them all lined up
under the microscope, each gets a little squirt
of CRISPR cocktail. [beep] Miles O’Brien:
They’re trying to “knock out” what Martin calls the
“master paintbrush genes” – ones they suspect control
wing shapes and patterns. Arnaud Martin:
And we say you “knock it out,” which is very imaginative,
right? You have lots of genes
in the genome, you take one that
you think is important, you knock it out
and you see what happens, what is going wrong. It’s like studying maybe
how our car is functioning, but you break a little part and you try to understand
what’s wrong, is it the wipers that are
stopping functioning, the electric system,
the engine, and so on. Miles O’Brien:
The eggs hatch into caterpillars, which eventually morph
into butterflies. They can actually watch
the wing patterns take shape every
step of the way. When unexpected shapes emerge, they know they’ve
found a master switch. Arnaud Martin:
Sometimes, the effect can be a little be predicted, based on the ways a gene is expressed during
wing development, when the wing is growing in
the caterpillar, in the larva, the genes are already
expressed in territories that are the future
wing patterns. So, sometimes, the master
switch gene we’re interested in, for instance,
is expressed as a stripe. And when we see that, we predict
that how she removes a gene, something looking like
the stripe is going to be gone and very often it has happened. Miles O’Brien:
It’s not all about butterflies. Variations on
the same master genes are also found in
the genomes of many animals, driving the development
of the shapes and the colors that
make each kind unique. Arnaud Martin:
So, this master switch, this mater paintbrush gene,
if you want, is of particular interest because we know that
in the genome, around this gene, there are a lot genomic change that is shaping biodiversity. We really want to dissect
that at the molecular level, go after the little details that really create novelty during evolution.
Miles O’Brien: Looking to butterflies
to understand the genomics of biodiversity. For Science Nation,
I’m Miles O’Brien.

2 thoughts on “The genetic path to biodiversity – Science Nation

  1. this is not a good use of budget in genome. would he please stop this . we need to notch out evil in people.

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