
Bajau tribe evolved huge spleens so they can dive deeper in the ocean - Eurongreyjoy
http://metro.co.uk/2018/04/19/tribe-of-fish-people-evolved-huge-spleens-so-they-can-dive-to-the-bottom-of-the-ocean-7481734/
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vatueil
Previous discussion, based on better NYT article:
[https://news.ycombinator.com/item?id=16881818](https://news.ycombinator.com/item?id=16881818)

Original paper in Cell (full text):
[http://dx.doi.org/10.1016/j.cell.2018.03.054](http://dx.doi.org/10.1016/j.cell.2018.03.054)

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nonbel
This is so ridiculous I'll repeat it in this thread.

The "enlarged spleens" they saw (~200 cm^3) are actually closer to _half_ the
size of typical spleens according to their own reference for spleen
measurement (~500 cm^3). They apparently found another group to compare to
with even smaller spleens, then acted like that was "normal" size to get this
enlarged spleen for diving narrative. Details here:
[https://news.ycombinator.com/item?id=16884186](https://news.ycombinator.com/item?id=16884186)

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aje403
Wow. Could there be any explanation for this or is this as bad as it looks? If
so, serious question, how do they get away with things like this? It's at
Cambridge, I mean you would have higher expectations? Maybe not?

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nonbel
It is common sense to check your control group measurements against the
literature and see where they stand. I would also expect to mention the
results of that search in the paper.

Looking closer at the paper I see they also had some spleen sizes from a
European cohort. They do not seem to tell us what those volumes were, instead
only reporting p-values. Can anyone find it?

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aje403
[http://www.humanfunctionalgenomics.org/site/?page_id=82](http://www.humanfunctionalgenomics.org/site/?page_id=82)
is what they used

Those don't appear to be spleen sizes, though. It looks like they're just
saying that they did a regression on some data linking "SNP"s to thyroid
hormone levels. Then, they did a different but similar regression on data from
the Bajau. I don't know what the relation of the SNPs are to spleen size but
don't see anything noted in that area of the paper. IANA social scientist, but
it looks quite goofy. They also note that they could not verify any
relationship between spleen and thyroid sizes anyway.

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nonbel
I think they did look at "other" spleen sizes and just chose not to mention
it. This really just looks like another case of "reject null hypothesis ->
conclude whatever we want".

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novalis78
So how did this evolve over the past 1000 years? Selection pressure? The
ancestor who could dive better had more children? Could feed his family
better? Was it just one person with mutation that started it? Or, did the
frequent exposure to deep diving triggered something in one generation that
influenced the genes of their children (along the lines of Epigenetic magic)?

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ed_balls
This ability gives you a huge competitive advantage in times of limited
resources, so most likely others have died/had limited offspring.

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bonzini
Even something more modest like "had on average 0.01 surviving offspring"
could make a big difference over many generations.

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schrectacular
The understanding of evolution in the title of this article is appalling...
They didn't evolve large spleens so they could dive.. they dove a lot which
resulted in selection bias which resulted in larger spleens...

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jessaustin
Replace "so" with its synonym "therefore" and the ambiguity is resolved in a
more pleasing way.

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schrectacular
Fair enough. When I see "so" used in this way I generally see it as meaning
"so that", which is also a perfectly valid inference. Perhaps it's an
Anlgo/American grammatical difference?

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jessaustin
Well it _is_ ambiguous, so that is a headline-writing failure. Especially
since this is a common misunderstanding of evolution anyway! In some sense
this would be a logical ambiguity even if the writer _meant_ to say that
adaptations are goal-driven. Headlines simply shouldn't be written like this.
Perhaps we're looking at this the wrong way, however. One gets the sense that
most journalists don't really concern themselves with logic and clarity of
thought anymore, since their intended audience is similarly unconcerned.

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mrfusion
How do wooden goggles work? What did they use for glass? How did they make a
seal?

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forgotmypw
Transparent oak

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pbhjpbhj
Huh, I was thinking it would just be a ledge like a pronounced monobrow,
strapped on and sealed to the head with either just pressure or pressure +
gum, that would catch exhaled air.

Wouldn't very thin wood implode?

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mrfusion
Wow sounds like we could take that thyroid hormone to enlarge our own spleen.
I wonder if divers have tried that.

