0:00
Hi, I'm Doug Soltis from
the University of Florida.
And today we're going to talk about
polyploidy, or genome doubling,
in flowering plants and show that
one plus one is better than two.
0:12
So let's start with some background.
We'll start with definitions:
what is genome doubling
or polyploidy,
define autopolyploids
versus allopolyploids, the
importance of polyploidy,
and then a bit about the
formation of polyploids.
0:30
After that background, we want to
overview some recent discoveries
in the field of genome doubling.
We'll reconsider some of
the traditional tenets
of polyploid evolution, looking
at the frequency of polyploidy,
polyploidy and its role
in diversification,
the importance of autoployploidy.
We'll talk about the multiple
origins of polyploids,
and then finally, discuss
polyploids as genomically
dynamic organisms, looking
at genomic expression,
chromosomal changes, and what we
can learn from the study of recently
formed polyploid species.
1:07
So let's get started.
Are you ready?
1:12
So let's begin with some
definitions as background,
and then from there,
we'll move quickly
into the importance of polyploidy.
1:22
As a simple definition, a
diploid nucleus contains
two copies of each chromosome,
but in a polyploid, the
nucleus contains three
or more copies of each chromosome.
Generally, two types of
polyploids are recognized,
autopolyploids and allopolyploids.
Autopolyploids generally
form from a single species.
You could imagine two diploid
populations of the same species.
Perhaps they hybridize,
chromosome doubling occurs,
and you end up with
an autopolyploid.
In an allopolyploid,
now we're dealing
with two closely related
species, diploid species A
and B. Imagine that they hybridize.
And here the chromosomes
are even color coded
so that you can tell them apart.
Again, the chromosome
number is doubled,
and we end up with an
allopolyploid with 20
chromosomes in this example.
