Name: 瘧疾和鐮狀細胞性貧血 -- -- HHMI生物交互式視頻 (Malaria and Sickle Cell Anemia — HHMI BioInteractive Video)
Uploaded: 2021-01-14T05:34:08.000Z
Duration: 14 min 16 s
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[NARRATOR:] Davaun and Skyy   Cooper are brother and sister.

sickle cell anemia almost certainly   meant death before adulthood.

Even today, young   patients can suffer strokes

Sickle cell anemia   is a genetic disease.

Parents of those who have   the disease might not have it

themselves, but both must   carry the sickle cell character

[DR. HEENEY:] How's it going?   Good. Can I see your hands?

This is pretty. Where did that   come from? Is that from Brookline?

[NARRATOR:] Besides some bone pain,   Skyy leads the fairly normal life

and has already had   his spleen removed.

[DR. HEENEY:] So you don't get any   more belly pains? That's good.

[NARRATOR:] Skyy and Davaun's   symptoms arise from the fact

that some of their red blood   cells become misshapen--

preventing enough oxygen   from being delivered

It's not completely clear   why symptoms are variable,

about sickle cell disease   is that it is not rare.

[DR. HEENEY:] So, in the United   States, we think there are

with sickle cell disease.   However, that doesn't take

into account immigration and   other patients or persons coming

from other parts of the   world into the country.

[NARRATOR:] In fact, in some   populations -- African Americans,

for example -- the incidence   is as high as 1 in 500,

astoundingly high for a   deadly inherited disease.

Didn't Darwin teach us that   harmful traits disappear

from the gene pool   through natural selection?

Why is sickle cell   anemia so prevalent,

and why in particular among   people of African descent?

The answers to these questions   began with a remarkable set

of observations from   an unlikely person more

[NARRATOR:] Tony Allison   has spent most of his career

as a medical doctor   and molecular biologist

But he grew up in East   Africa and he is quick

to recall his formative   years in Kenya.

[DR. ALLISON:] We lived in the   upcountry, and we used to go

to the coast every year   in August for the holiday

when it was a little bit   cooler than at other times.

So we had the trip all the   way down, which was usually

And, so we would camp   on the way and, in Tsavo

and there would be   lions roaming around,

[DR. CARROLL:] These are   the infamous Tsavo lions--

[DR. ALLISON:] The famous--   infamous Tsavo lions--

[DR. CARROLL:] Around 1950,   biologists didn't know a lot

because we didn't know   really how heredity worked.

The structure of DNA had   not been discovered yet,

So, we know that, while evolution   was due to genetic changes,

we didn't know how those genetic   changes took place whatsoever.

So, there were holes   in the whole picture

and Tony Allison was probably   the least-likely person you

would imagine, who would fill   one of the most critical holes.

He grew up far away from   the centers of science

He was really interested   in natural history

But it was a really circuitous   and serendipitous route

[NARRATOR:] Tony first went   to University in South Africa

where he studied   physical anthropology,

He had a deep interest in   human origins, but not so much

Could the common ABO   blood types say anything

about the evolutionary history   of East African tribal people?

[DR. ALLISON:] And I actually   learned just before going

carrying the sickle   cell character appear quite

Tony learned that   adding a chemical agent

to the samples would   quickly reduce oxygen

and reveal sickle cells,   if they were there.

This gave him an easy test   to score blood samples

[DR. ALLISON:] But   what was striking was

of people carrying the sickle   cell character in the coast

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瘧疾和鐮狀細胞性貧血 -- -- HHMI生物交互式視頻 (Malaria and Sickle Cell Anemia — HHMI BioInteractive Video)

character

disease

correlation

evolutionary