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AP Biology Chapter 18 Genomes and Their Evolution | The data on this slide, this is nothing you need to memorize. |
AP Biology Chapter 18 Genomes and Their Evolution | Actually, if you look at the data, this slide is almost 10 years old in terms of the data
on it. |
AP Biology Chapter 18 Genomes and Their Evolution | It just gives you some ideas as to the size and complexity of genomes. |
AP Biology Chapter 18 Genomes and Their Evolution | I want to actually use this slide to analyze because the AP exam, none of this should you
memorize of course, but they could give you data to analyze. |
AP Biology Chapter 18 Genomes and Their Evolution | Let's just go through this together quickly. |
AP Biology Chapter 18 Genomes and Their Evolution | I have domain bacteria, domain archaea, and domain eukarya. |
AP Biology Chapter 18 Genomes and Their Evolution | We haven't done the domains yet, really. |
AP Biology Chapter 18 Genomes and Their Evolution | Both of these are what back in the day you would call bacteria. |
AP Biology Chapter 18 Genomes and Their Evolution | Eukarya is plants, algae, animals, and protists. |
AP Biology Chapter 18 Genomes and Their Evolution | You're in eukarya. |
AP Biology Chapter 18 Genomes and Their Evolution | Genome size. |
AP Biology Chapter 18 Genomes and Their Evolution | The MB is megabases, which is millions of bases. |
AP Biology Chapter 18 Genomes and Their Evolution | Obviously, eukaryotes have between 10 and 40,000 million bases, much larger genomes
than bacteria. |
AP Biology Chapter 18 Genomes and Their Evolution | Number of genes. |
AP Biology Chapter 18 Genomes and Their Evolution | How many genes does it take to make a bacteria? |
AP Biology Chapter 18 Genomes and Their Evolution | So 1,500 to close to 8,000. |
AP Biology Chapter 18 Genomes and Their Evolution | For eukaryotic cells, obviously, it's much higher. |
AP Biology Chapter 18 Genomes and Their Evolution | Gene density though is the number of genes inside the genome. |
AP Biology Chapter 18 Genomes and Their Evolution | So it's like a unit of, well, it's a unit of density. |
AP Biology Chapter 18 Genomes and Their Evolution | And notice that bacteria have a higher gene density than eukaryotes. |
AP Biology Chapter 18 Genomes and Their Evolution | Bacteria have fewer genes, right? |
AP Biology Chapter 18 Genomes and Their Evolution | But the density is higher because they have fewer bases. |
AP Biology Chapter 18 Genomes and Their Evolution | Lots of the DNA in eukaryotes is, it's not, when I was in school, we called it junk DNA. |
AP Biology Chapter 18 Genomes and Their Evolution | It's really not junk. |
AP Biology Chapter 18 Genomes and Their Evolution | There's a reason for it. |
AP Biology Chapter 18 Genomes and Their Evolution | If it's DNA, it doesn't actually code for proteins. |
AP Biology Chapter 18 Genomes and Their Evolution | And we discussed introns and exons. |
AP Biology Chapter 18 Genomes and Their Evolution | Bacteria don't have introns. |
AP Biology Chapter 18 Genomes and Their Evolution | Some types of archaea do have introns. |
AP Biology Chapter 18 Genomes and Their Evolution | Your cells, eukaryotic cells, have introns that you have to cut out. |
AP Biology Chapter 18 Genomes and Their Evolution | Again, other reasons of non-coding DNA. |
AP Biology Chapter 18 Genomes and Their Evolution | DNA that doesn't code for proteins or messenger RNAs. |
AP Biology Chapter 18 Genomes and Their Evolution | Very, very little. |
AP Biology Chapter 18 Genomes and Their Evolution | In bacteria, you have lots of non-coding DNA. |
AP Biology Chapter 18 Genomes and Their Evolution | We use the term junk DNA. |
AP Biology Chapter 18 Genomes and Their Evolution | The term non-coding DNA is a much better term. |
AP Biology Chapter 18 Genomes and Their Evolution | So let's just look at this. |
AP Biology Chapter 18 Genomes and Their Evolution | So you actually know what? |
AP Biology Chapter 18 Genomes and Their Evolution | I'm not actually presenting this presentation. |
AP Biology Chapter 18 Genomes and Their Evolution | Let's do it. |
AP Biology Chapter 18 Genomes and Their Evolution | Let me normally do it. |
AP Biology Chapter 18 Genomes and Their Evolution | Make it bigger. |
AP Biology Chapter 18 Genomes and Their Evolution | There we go. |
AP Biology Chapter 18 Genomes and Their Evolution | That's how it usually looks. |
AP Biology Chapter 18 Genomes and Their Evolution | Okay. |
AP Biology Chapter 18 Genomes and Their Evolution | So let's just look. |
AP Biology Chapter 18 Genomes and Their Evolution | So how many genes does it take to make a human? |
AP Biology Chapter 18 Genomes and Their Evolution | So here's human, homo sapiens. |
AP Biology Chapter 18 Genomes and Their Evolution | Just under 21,000 genes to make a human. |
AP Biology Chapter 18 Genomes and Their Evolution | That's all you need. |
AP Biology Chapter 18 Genomes and Their Evolution | Compare that to rice, over 40,000. |
AP Biology Chapter 18 Genomes and Their Evolution | Compare that to corn, 32,000. |
AP Biology Chapter 18 Genomes and Their Evolution | It takes more genes to make corn than it does to make a human. |
AP Biology Chapter 18 Genomes and Their Evolution | What else is surprising? |
AP Biology Chapter 18 Genomes and Their Evolution | The mustard family, mustard plants, have more genes than humans do. |
AP Biology Chapter 18 Genomes and Their Evolution | Bacteria, again, look at the numbers. |
AP Biology Chapter 18 Genomes and Their Evolution | Just over 1,000 to 4,000 or 5,000. |
AP Biology Chapter 18 Genomes and Their Evolution | To me, that's surprising. |
AP Biology Chapter 18 Genomes and Their Evolution | It takes 21,000 genes more or less to make a human. |
AP Biology Chapter 18 Genomes and Their Evolution | So in terms of numbers of genes, you can read this yourself. |
AP Biology Chapter 18 Genomes and Their Evolution | The main thing I want you to know from this slide is this last point, which we've already
discussed. |
AP Biology Chapter 18 Genomes and Their Evolution | 21,000 genes isn't a lot of genes to make a human, but you do alternative DNA splicing
or actually RNA splicing, a messenger RNAs. |
AP Biology Chapter 18 Genomes and Their Evolution | You can splice genes different ways. |
AP Biology Chapter 18 Genomes and Their Evolution | The one gene in humans could actually become multiple different types of messenger RNAs
based upon alternative splicing, which bacteria don't do. |
AP Biology Chapter 18 Genomes and Their Evolution | You can get away with only having 21,000 genes because you can splice them different ways. |
AP Biology Chapter 18 Genomes and Their Evolution | This slide starts us into a slightly different topic. |
AP Biology Chapter 18 Genomes and Their Evolution | So chapter 19, we're going to start evolution. |
AP Biology Chapter 18 Genomes and Their Evolution | The ultimate source of new genes is mutation. |
AP Biology Chapter 18 Genomes and Their Evolution | I understand theoretically how you go from normal hemoglobin to sickle cell. |
AP Biology Chapter 18 Genomes and Their Evolution | It's a point mutation of a single base changing one amino acid like that. |
AP Biology Chapter 18 Genomes and Their Evolution | I get how mutations can create new genes, but what I don't fully get or what's much harder
to understand conceptually is how do you evolve hemoglobin in the first place? |
AP Biology Chapter 18 Genomes and Their Evolution | Where did those 21,000 genes come from? |
AP Biology Chapter 18 Genomes and Their Evolution | I get the gene they can mutate, but how is it that I can create such complex organisms
based upon a process that's largely random in mutations? |
AP Biology Chapter 18 Genomes and Their Evolution | Biology can't fully answer that question, to be honest. |
AP Biology Chapter 18 Genomes and Their Evolution | I don't have an answer for you, but there are some things that happen in cells that
help you to understand how you can evolve different types of hemoglobin. |
AP Biology Chapter 18 Genomes and Their Evolution | Pseudo genes are copies of genes in your DNA that don't work anymore. |
AP Biology Chapter 18 Genomes and Their Evolution | You have a gene for hemoglobin. |
AP Biology Chapter 18 Genomes and Their Evolution | Elsewhere in your genome, there are copies of the gene for hemoglobin that are mutated
and don't work anymore. |
AP Biology Chapter 18 Genomes and Their Evolution | Like, what? |
AP Biology Chapter 18 Genomes and Their Evolution | Where did those come from? |
AP Biology Chapter 18 Genomes and Their Evolution | What the heck is that? |
AP Biology Chapter 18 Genomes and Their Evolution | Every DNA is just DNA that repeats, it has multiple copies of the same DNA. |
AP Biology Chapter 18 Genomes and Their Evolution | The way that you get things like pseudogenes is very interesting. |
AP Biology Chapter 18 Genomes and Their Evolution | It doesn't seem to directly relate to evolution, but it actually does if you think about it. |
AP Biology Chapter 18 Genomes and Their Evolution | For example, I actually will give you some examples in a minute, but you have genes in
your body that make very different proteins, but the sequence of those genes is very, very,
very similar. |
AP Biology Chapter 18 Genomes and Their Evolution | Maybe they originated from one gene that got duplicated, and those two versions evolved
different ways to today to give you way different proteins, but because their sequences are
so similar, it's like, well, that can't just be a coincidence. |
AP Biology Chapter 18 Genomes and Their Evolution | This chart just shows only 1.5% of your DNA is exons, is actually coding. |
AP Biology Chapter 18 Genomes and Their Evolution | The rest are regulatory sequences like promoters, introns that get cut out, unique non-coding,
repetitive DNA, transposons, things that we're going to see in a minute. |
AP Biology Chapter 18 Genomes and Their Evolution | You don't need to have these numbers memorized. |
AP Biology Chapter 18 Genomes and Their Evolution | This just shows you that most of your DNA doesn't actually code for proteins. |
AP Biology Chapter 18 Genomes and Their Evolution | This leads us to a story. |
AP Biology Chapter 18 Genomes and Their Evolution | Again, this story might not be obvious how it relates to evolution, but it totally does. |
AP Biology Chapter 18 Genomes and Their Evolution | Barbara McClintock was a scientist, a geneticist. |
AP Biology Chapter 18 Genomes and Their Evolution | She's American. |
AP Biology Chapter 18 Genomes and Their Evolution | She's working somewhere in New England. |
AP Biology Chapter 18 Genomes and Their Evolution | I forget what state. |
AP Biology Chapter 18 Genomes and Their Evolution | This is the middle of the 20th century. |
AP Biology Chapter 18 Genomes and Their Evolution | She proposes these things called transposons or transposable elements. |
AP Biology Chapter 18 Genomes and Their Evolution | This is going to sound crazy at first. |
AP Biology Chapter 18 Genomes and Their Evolution | When she first proposed this, people did not accept it at all. |
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