Jonathan Lambert

So in general, all these efforts try to guess the genes and proteins that Luca had by looking for what's shared across different organisms. Like, for example, if you compare a gene that's basically the same in us and chimps, it's pretty safe to say that we inherited it from our common ancestor. That's the simplest explanation.

So in general, all these efforts try to guess the genes and proteins that Luca had by looking for what's shared across different organisms. Like, for example, if you compare a gene that's basically the same in us and chimps, it's pretty safe to say that we inherited it from our common ancestor. That's the simplest explanation.

But that kind of inference gets a lot more complicated the further back in time you go.

But that kind of inference gets a lot more complicated the further back in time you go.

But that kind of inference gets a lot more complicated the further back in time you go.

Well, genes get up to a lot of shenanigans that can throw off that detective work.

Well, genes get up to a lot of shenanigans that can throw off that detective work.

Well, genes get up to a lot of shenanigans that can throw off that detective work.

Yeah, so there's horizontal gene transfer, which is this thing where instead of passing genes vertically from one generation to the next, some microbes can pass them horizontally to their neighbors. Like a bacterium can give its other bacteria friends antibiotic resistance, for example, when it butts up against them and shares that little bit of DNA.

Yeah, so there's horizontal gene transfer, which is this thing where instead of passing genes vertically from one generation to the next, some microbes can pass them horizontally to their neighbors. Like a bacterium can give its other bacteria friends antibiotic resistance, for example, when it butts up against them and shares that little bit of DNA.

Yeah, so there's horizontal gene transfer, which is this thing where instead of passing genes vertically from one generation to the next, some microbes can pass them horizontally to their neighbors. Like a bacterium can give its other bacteria friends antibiotic resistance, for example, when it butts up against them and shares that little bit of DNA.

And so that can make it seem like a bunch of species all inherited this gene from a common ancestor when in reality it just got shared a bunch.

And so that can make it seem like a bunch of species all inherited this gene from a common ancestor when in reality it just got shared a bunch.

And so that can make it seem like a bunch of species all inherited this gene from a common ancestor when in reality it just got shared a bunch.

Yeah. And then there's the issue of genes getting lost, but only for some species. Like if genes that were in LUCA get lost down the line in certain species, it could lead researchers to falsely conclude that the genes evolved after LUCA since it's not shared by all its descendants. Right.

Yeah. And then there's the issue of genes getting lost, but only for some species. Like if genes that were in LUCA get lost down the line in certain species, it could lead researchers to falsely conclude that the genes evolved after LUCA since it's not shared by all its descendants. Right.

Yeah. And then there's the issue of genes getting lost, but only for some species. Like if genes that were in LUCA get lost down the line in certain species, it could lead researchers to falsely conclude that the genes evolved after LUCA since it's not shared by all its descendants. Right.

Exactly. Lots and lots of stuff that muddies the waters.

Exactly. Lots and lots of stuff that muddies the waters.

Exactly. Lots and lots of stuff that muddies the waters.