Ancient virus may be protecting the human placenta

https://www.science.org/content/article/ancient-virus-may-be-protecting-human-placenta

by Vigier • 4 years ago

50 19 4 years ago

wan_ala• 4 years ago

Does anybody know if there is a less vague date than "millions of years ago" as to when this retrovirus started becoming apart of human DNA? Were we even humans at the moment?

e40• 4 years ago

I listened to a podcast on this and they said it allowed the placenta to evolve in the first place. That's what I remember. Anyone else?

type0• 4 years ago

I've read it in some pop sci book on genetics as well that without retroviruses we wouldn't have placental mammals, it's certainly convincing theory given how weirdly these cells need to behave.

cultofmetatron• 4 years ago

primates aren't the only placental mammals though

_Microft• 4 years ago

About 30 million years ago, a virus infected our primate ancestors and one of its genes got trapped in their genomes.

chatmasta• 4 years ago

So at +/- 1 million, that's a range of 29-31 million, or three million years. That still seems imprecise, to be fair.

For any virologists out there, is this question similar to estimating the date of a Git commit? Or maybe it's similar to finding the nearest tag to a given commit, where a "tag" is some external reference point with a known date (like a fossil or ice core)?

cguess• 4 years ago

Literally the first line of the article.

madrox2• 4 years ago

This is not my field and my understanding of it is limited to high school science, but a picture being painted for me as a naive consumer of scientific news is that we're seeing evidence that viruses are playing a role in evolution. We get infected with things that alter our DNA, and sometimes those alterations give us advantages.

It leads me to wonder if there's a role mosquitos play in our ecosystem after all. It's long held that mosquitos serve no positive purpose in ecosystems and ought to be eradicated when possible. When confronting the affects of malaria, it's hard to argue against the idea, but it's certainly true that mosquitos are an effective virus delivery mechanism. If sometimes viruses play to our advantage, maybe there's more to the insect's role.

Or maybe I just need to read more.

clolege• 4 years ago

mosquitos serve no positive purpose in ecosystems and ought to be eradicated when possible

I've heard the same, but it really feels like a naïve take. We can't know for sure that they have no positive purpose in their ecosystems, and eradicating them is a one way street.

No idea where the belief came from, but it's a bit concerning how widely held it is.

madrox2• 4 years ago

This is, of course, the counterargument to eradication, which is what leads me to muse on it

alar44• 4 years ago

As I've read it, it's always regarding the food chain. I've never seen a paper that said mosquitos were completely inconsequential, just that if they were completely removed, the food chain wouldn't be damaged.

yarg3• 4 years ago

Somewhat tangentially, a mosquito eradication effort increased the rates of Dengue hemorrhagic fever - the opposite of what was intended.

With Dengue, if the body is exposed to multiple strains within a short time period, there's no severe reaction.

However, if there's a delay, and the body gets to prepare, and then sees a slightly different Dengue virus, the shit hits the fan.

So the decreased number of mosquitos left a greater mean time between cross-strain exposure, which in turn increased the number of severe reactions.

Ancient virus may be protecting the human placenta

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