
Early humans in Africa may have interbred with an extinct species: new research - diodorus
https://theconversation.com/early-humans-in-africa-may-have-interbred-with-a-mysterious-extinct-species-new-research-131699
======
TallGuyShort
How do we draw the line between species, exactly? Similar to this, you can
distinguish between races and genders with skeletal tendencies now, but we're
all one species. So when they are compatible enough to bone each other and
said boning yields offspring, what exactly determines the line between 2
species and 2 distinct populations of 1 species?

edit: I'm also always intrigued by statements like this: "Interestingly, they
suggest that 6%-7% of the genomes of West Africans is archaic in origin". I
know it's over-simplifying for the lay-person, but 6-7% is the high end of
what people claim is the genetic difference between us and chimpanzees, and we
can't even reproduce with chimpanzees and don't even have the same number of
chromosomes. So there's a lot more than that we have in common with _some_
archaic species, and a lot less that we'd expect to have with closer
relatives.

~~~
angstrom
I mean. Donkey+Horse = Mule, but the mule is sterile same with Tiger+Lion =
Liger. I would assume they were closer relatives than that.

~~~
tmn
A liger isn't sterile. It does have a lower chance of conception though

~~~
yellowapple
Technically a mule also has a lower chance of conception.

------
s1artibartfast
One thing that I always struggle with in these arciles is how the percent of
common DNA is defined.

>We still think that most – anywhere between about 92% and 98.5% – of the
ancestry in people not living in Africa today does indeed derive from the out-
of-Africa expansion.

>Interestingly, they suggest that 6%-7% of the genomes of West Africans is
archaic in origin. But this archaic ancestry wasn’t Neanderthal or Denisovan.

How are these numbers reconciled with other statements like 99% of the human
genome is shared with Bonobos [1]

[https://www.sciencemag.org/news/2012/06/bonobos-join-
chimps-...](https://www.sciencemag.org/news/2012/06/bonobos-join-chimps-
closest-human-relatives)

~~~
waserwill
Re: definitions of shared DNA:

Some papers will use different definitions, and it can be confusing.

Between species (e.g. humans and chimps), it's most often considering "non-
synonymous mutations," i.e. how many genetic differences there are in protein-
coding genes (these are relevant to structure and function of the protein)

For distant relatives (e.g. humans and bananas), it's similar, looking
specially at those genes which we can identify across many species
(particularly those related to cell upkeep, DNA replication, structure, etc.).

For within-species, there are a few ways of doing it; you could model how much
of the genome you expect came from each source (as this study did) (see
admixture analysis, coalescence), and you could look for overall differences
on the genome (of all existing variation in the species, how much is
consistently different between populations) (see F-statistics for example)

~~~
s1artibartfast
Thank you. This is very helpful!

------
magduf
Was it a small group of humanoids that came from another star system composed
of 12 colonies after being pursued by a society of artificial lifeforms that
was bent on their extermination?

~~~
DiabloD3
The real question is: was Kara Thrace, at any point, actually real?

~~~
dntbnmpls
Of course she was real. She had a mother, history and upbringing. Now as to
whether the post-death Thrace ( "the second coming" ) was the "spirit/angel"
of Thrace or an altogether different entity separate from Thrace ( like
physical Gaius and the "spiritual/angelic/head" Gaius you see at the end of
the series ) that's up for debate.

Her destiny ( teased throughout the series ) was to sacrifice herself to lead
humanity to salvation ( earth ). It's similar to Christ in a way - self-
sacrifice and the second coming to lead the faithful to the kingdom of god.

~~~
DiabloD3
I've watched through BSG I think 3 times over the years, and I've come to the
conclusion that I don't think she was strictly human, in the normal sense.

I think from day one of her existence, she was a kind of power on the same
level as Baltar and Six's angelic alter egos. Watching it the first time when
it originally aired, I had thought she was one of the Five (even though part
of me thought that was too obvious, and a cop out)... and then the fifth
member was revealed and it wasn't her.

Clearly the writers had given her a role beyond merely human or Cylon,
something part of the grand scheme of God that Messenger/Head Baltar and Six
were part of.

------
nikolay
[https://phys.org/news/2013-07-chimp-pig-hybrid-
humans.html](https://phys.org/news/2013-07-chimp-pig-hybrid-humans.html)

~~~
wildermuthn
I love this theory. Not because I believe it, but because of how entrancingly
bold it is. I sometimes wonder what we believe in that future generations will
look down upon us for. Surely we haven’t discovered everything, right? Surely
there are some things we think we know that is actually completely wrong.

Is it that human origins are rooted in chimp-pig hybridization? Probably not,
but it is high on my “just might be crazy enough to be right” list. The odd
similarity-dissimilarities among human, pig, and primate are just too
interesting to be dismissed out of hand.

~~~
nikolay
Exactly my point as well - science shouldn't shy away from stuff we wouldn't
like. That's why I also respect Copernicus, Darwin, and Freud so much - they
dared to tell us things we didn't like, but they didn't care much; they only
cared about the scientific truth.

------
mr_overalls
In an intro-level anthropology class I took 20 years ago, we learned about the
competing models of human evolution: Multiregional vs Out of Africa.

Perhaps they dumbed down the complexity for a bunch of freshmen, but I
remember wondering then why some combination of the two wasn't possible.

It certainly looks like a mix of the two canonical models matches the data
that is being revealed through genetics.

~~~
turtlecloud
my suspicion is that the out of Africa theory was promoted since it was more
PC. Nowadays the "scientific theories" are all political.

~~~
TallGuyShort
Out of Africa feels less PC to me, but I won't pretend to understand the
rationale behind what is and isn't considered PC a lot of the time. But I
agree with GP: we have relatively few DNA samples and try to draw pretty big
generalizations between them. Ituitively, I would expect patterns of migration
in and out of Africa and all the continents to be far more complex than 1-time
events from which entire populations then developed complete independently.

edit: On a related note, my siblings' DNA test results say that they're
something like 4% Native American, yet we have very reliable documentation of
pure British genealogy back on all lines almost all the way back to the 1500s.
Very unlikely to actual have a modern link. I'm sure the companies are likely
overplaying the similarity more than anthropologists would, but am I to
conclude that I have a closer link to Native Americans than other random
samples from Europe?

~~~
progval
> I won't pretend to understand the rationale behind what is and isn't
> considered PC a lot of the time.

It's whatever opinion/theory the person speaking disagrees with.

~~~
dominostars
The poster clearly said that so that they can stay on topic, not sure we need
to derail the main conversation to air personal grievances.

------
golemotron
Species is a social construct.

~~~
TheGallopedHigh
/s ?

~~~
lazyier
you start to realize that the color blue is a social construct if you are
willing to abandon all reason.

~~~
krapp
Except the color blue _is_ at least partially a social construct[0].

[0][https://tvtropes.org/pmwiki/pmwiki.php/UsefulNotes/GreenIsBl...](https://tvtropes.org/pmwiki/pmwiki.php/UsefulNotes/GreenIsBlue)

~~~
tenpies
Does that make the colour blue a social construct, or the word blue a social
construct?

After all, #0000ff is #0000ff no matter what you call it or through whose eyes
it reflect photons. ;)

~~~
krapp
#0000ff doesn't exist in nature. Human beings don't see color directly in
hexadecimal values - indeed, additive color (RGB) as broadcast from a monitor
and subtractive color as exists in nature are physically different processes.
Rather, the perception of color is subjective and error prone (see a HN
subthread on the color brown[0,1] or other examples of color illusions like
the viral dress from a few years ago, or the red-grey illusion[2].

Blue is a social construct because what "blue" means is taught to us by the
culture around us, and different cultures classify colors differently[3,4]. If
one culture considers blue and green to be the same color, and another
considers them distinct, that's not merely a disagreement over taxonomy, but
concept.

[0][https://news.ycombinator.com/item?id=22324298](https://news.ycombinator.com/item?id=22324298)

[1][https://news.ycombinator.com/reply?id=22326975&goto=item%3Fi...](https://news.ycombinator.com/reply?id=22326975&goto=item%3Fid%3D22324298%2322326975)

[2][https://www.vice.com/en_us/article/wnkq5n/this-picture-
has-n...](https://www.vice.com/en_us/article/wnkq5n/this-picture-has-no-red-
pixelsso-why-do-the-strawberries-still-look-red)

[3][https://en.wikipedia.org/wiki/Blue%E2%80%93green_distinction...](https://en.wikipedia.org/wiki/Blue%E2%80%93green_distinction_in_language)

[4][https://en.wikipedia.org/wiki/Linguistic_relativity_and_the_...](https://en.wikipedia.org/wiki/Linguistic_relativity_and_the_color_naming_debate)

------
Razengan
I've always wondered.. If there ever was another sapient species on this
planet we either killed them all or interbred with them, or they went into
hiding.

~~~
duxup
Or they died out long before we appeared:

[https://en.wikipedia.org/wiki/Silurian_hypothesis](https://en.wikipedia.org/wiki/Silurian_hypothesis)

~~~
tenpies
Not mentioned in that Wikipedia article, but the explanation for "why is there
no ancient plastic around" is that the civilization could have pre-dated oil.
Not enough time may have passed for significant amounts of the stuff to
accumulate in the planet, so the civilization would have never developed a use
for it. It would have been a rarity to them, not a foundational cornerstone of
civilization.

It's a cool thought experiment, but also very cool to think about how much we
lucked out not just to be on Earth, but to be on Earth at this point in time.
Emerge a bit earlier and suddenly industrialization becomes exponentially
harder.

~~~
duxup
And an Earth with ... a lot of handy animals and such!

------
losvedir
> _The interbreeding outside Africa happened after our Homo sapiens ancestors
> expanded out of Africa into new environments._

Who's this "our"? Is the author implicitly excluding Africans from her
audience (or whoever she's talking about), or do I have the timeline wrong and
the aforementioned interbreeding ancestors went _back_ to Africa, and _then_
the "Out of Africa" expansion happened?

~~~
pessimizer
As a black person of African descent, I feel confident in saying that the
group called homo sapiens, of which I and all of my ancestors for millennia am
a part, expanded out of Africa into new environments.

------
jojostrikesback
Definition of species is not clear cut.

------
kmerrol
I'm not sure about extinct. My brother in-law is definitely a living example
of a new mysterious species of human.

~~~
christiansakai
One of why I like HN is that the posts and comments are generally serious and
comments like these are down-voted.

But nevertheless, I become 2 years old every time I encounter comments like
this. Thanks for the good laugh.

------
williesleg
I love hacker news! So much tech going on here!

