One plus one is better than two: genome doubling in flowering plants

Published on December 1, 2013   36 min

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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.
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One plus one is better than two: genome doubling in flowering plants

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