Rundown 4 — Genes that may predate LUCA (universal paralogs)

1:01:02What does that even What does that mean? >> Yeah, that doesn't that doesn't mean anything to me, right? Genes before life. >> What are you talking about? is exactly what I thought when I was when I was reading this because like it's like life is genes, >> right? So, how does it before? >> Yeah. Yeah. Yeah. So, here here's what's going on. There might be some genes that are in nearly every single organism today that were duplicated before life shared a common ancestor. >> Okay. >> Okay. Because let's think about all of life on Earth, right? It came from a single common ancestor. That's what we think because we all have DNA and there's all these different markers, right? Now that single common ancestor,

1:01:45>> there must have been stuff before the common ancestor that were building blocks to make that last common ancestor right? >> And these guys are saying they have a way now to find genes that were there before that last common ancestor was even alive. Like the building blocks of that last common ancestor. It's pretty insane. So when we think about the lost common ancestor, right, these are cells that already had membranes. They've got an inside and an outside and they've got DNA to store genetic information, right? To store some information for self-replication. Now, these are essential traits and they've already been established. So, what happened before that? And how can we tell? Well, they look for something

1:02:25called paralogues. Okay, paralogues are groups of related genes that appear multiple times within a single genome. >> A good example is for us um hemoglobin. We have eight copies of hemoglobin in our DNA. Okay? And that hemoglobin came about about 800 million years ago. That's the thing, that's the protein that carries oxygen in our blood. We've got eight different copies. All of us have eight eight different different copies. A lot of mammals have eight different copies. The fact that all of us have that means that hemoglobin is a really old old protein. >> Okay? So the idea is if there's repeated copying and extra versions of this gene then the copying must have happened way

1:03:08early because all of us have that >> right >> so now let's look for universal paralogues >> which are genes that are repeated that like they have this repeated tendency and these copies across everyone >> bacteria us fungi literally everyone. What they're looking for is gene families that appear at least two times in at least two copies in the genomes across life. >> And so to be clear, you're saying hemoglobin there's eight copies. >> Eight copies, but it only happened 800 million years ago, right? >> Like bacteria don't have hemoglobin, >> right? And so so we're >> plants also, >> we're looking for things that have multiple copies like hemoglobin,

1:03:50>> but hemoglobin we only see in humans and mammals. And so we're saying what else has these n number of multiple copies? But in other >> everywhere but literally everywhere. That's the other thing. It's got to be literally everywhere because then you can make the argument it happened way back even before the universal ancestor, >> right? And they found a few >> and all of these all of these genes have to do with two things. Either building proteins or managing the membrane, how to get in and out of the membrane. And that kind of makes sense. We've talked about this, you've brought this up several times about the membrane and it's like how did

1:04:30that happen? >> How did that happen? >> The it turns out these cell membranes and managing transport across the cell membrane is something that might have happened even before our last common ancestor just in like random molecular processes and like proteins at a molecular level. Not even a cell trying to self-replicate, but like molecules trying to get across. And if a molecule got across, it had an advantage to like do more of itself, >> right? >> Um, and I think that's that's really fascinating. What they could also do is reconstruct the protein and produce this ancient ancestral protein >> that could then go across molecules. >> We It's molecular Jurassic Park.

1:05:11>> Yes. Yes. It's And what's crazy is that molecule that's, you know, billions of years old now, it can traverse the same molec the the same membranes that we have. Yeah. And so >> so so that that old um you know use case is it it can still do it. >> It's it's like we've found we've like reburned a CD copy of now that's what I call music volume 4 >> and we're on now that's what I call music volume 200. Yeah. >> But it's like it's >> but it's like we found the old >> and you got the same intro same and it work it plays in the same player. That's kind of a a rough analogy, but but that's actually so >> I thought that was really crazy.

1:05:51>> This is very cool because again, what this means is we can continue to log >> and continue to look for these paralogues across everything that would create that would allow us to identify these ancestors before the currently accepted universal common ancestor in terms of traversing the path of evolution from like single cell to multisellular organisms. >> Yeah. >> Unbelievable. This is out of uh Oberlin College, MIT. I misdated MIT earlier. This was the MIT story. And our our Midwest companions UWMadison and cell genomics. >> We're going to move to our last rundown story which is about astrophysics and

1:06:32exoplanets. Uh which, you know, astronomers have