[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:21.38,0:00:30.66,Default,,0000,0000,0000,,MORGAN GRACE: I think I kind of always knew that I had something different than other kids.
Dialogue: 0,0:00:30.66,0:00:33.84,Default,,0000,0000,0000,,I have danced since I can remember.
Dialogue: 0,0:00:33.84,0:00:36.52,Default,,0000,0000,0000,,Whenever I hear any kind of music,
Dialogue: 0,0:00:36.52,0:00:38.92,Default,,0000,0000,0000,,I can't just sit still.
Dialogue: 0,0:00:40.85,0:00:44.47,Default,,0000,0000,0000,,I loved being on stage.
Dialogue: 0,0:00:46.75,0:00:51.99,Default,,0000,0000,0000,,It started to like get worse as I was going through puberty.
Dialogue: 0,0:00:52.47,0:00:58.97,Default,,0000,0000,0000,,But I just remember a wave of pain washed over my body.
Dialogue: 0,0:00:58.97,0:01:02.49,Default,,0000,0000,0000,,When I go through a bad pain crisis,
Dialogue: 0,0:01:02.49,0:01:05.11,Default,,0000,0000,0000,,they come out of nowhere.
Dialogue: 0,0:01:06.07,0:01:13.47,Default,,0000,0000,0000,,I had to quit dancing because of being in the hospital.
Dialogue: 0,0:01:13.62,0:01:19.35,Default,,0000,0000,0000,,It just made a lot of things in my life have to stop.
Dialogue: 0,0:01:19.73,0:01:22.21,Default,,0000,0000,0000,,MORGAN'S MOM: Morgan!
Dialogue: 0,0:01:24.98,0:01:28.70,Default,,0000,0000,0000,,Narrator: Morgan has sickle cell disease,
Dialogue: 0,0:01:28.70,0:01:33.26,Default,,0000,0000,0000,,an inherited condition that affects her red blood cells.
Dialogue: 0,0:01:34.02,0:01:40.74,Default,,0000,0000,0000,,Before modern medicine, many people with this disease didn't survive into adulthood.
Dialogue: 0,0:01:41.18,0:01:48.00,Default,,0000,0000,0000,,The theory of evolution by natural selection predicts that harmful traits should be rare.
Dialogue: 0,0:01:48.00,0:01:53.34,Default,,0000,0000,0000,,But what's so puzzling about sickle cell is that it's relatively common,
Dialogue: 0,0:01:53.34,0:01:57.74,Default,,0000,0000,0000,,especially in people with ancestry from certain parts of the world.
Dialogue: 0,0:01:57.74,0:02:03.80,Default,,0000,0000,0000,,Figuring out why this harmful trait is so common will take us on a remarkable journey
Dialogue: 0,0:02:03.80,0:02:26.05,Default,,0000,0000,0000,,of scientific discovery.
Dialogue: 0,0:02:26.05,0:02:27.85,Default,,0000,0000,0000,,NURSE: Dr. Acher will see you.
Dialogue: 0,0:02:31.76,0:02:36.76,Default,,0000,0000,0000,,DR. NATASHA ARCHER: Hematology is the study of blood disorders.
Dialogue: 0,0:02:37.64,0:02:45.48,Default,,0000,0000,0000,,A pediatric hematologist takes care of children with those blood disorders.
Dialogue: 0,0:02:45.48,0:02:48.08,Default,,0000,0000,0000,,Hi. How are you?
Dialogue: 0,0:02:48.08,0:02:48.59,Default,,0000,0000,0000,,MORGAN GRACE: I'm good.
Dialogue: 0,0:02:48.59,0:02:49.70,Default,,0000,0000,0000,,DR. ARCHER: You started school already?
Dialogue: 0,0:02:49.70,0:02:51.34,Default,,0000,0000,0000,,MORGAN GRACE: Yes, I started last week.
Dialogue: 0,0:02:51.34,0:02:53.62,Default,,0000,0000,0000,,DR. ARCHER: I really got interested in hematology when
Dialogue: 0,0:02:53.62,0:02:57.51,Default,,0000,0000,0000,,I started to meet patients who had sickle cell disease.
Dialogue: 0,0:02:58.24,0:03:04.28,Default,,0000,0000,0000,,NARRATOR: Sickle cell disease is caused by a change or mutation in a single gene.
Dialogue: 0,0:03:04.28,0:03:08.64,Default,,0000,0000,0000,,The gene codes for a subunit of the protein hemoglobin,
Dialogue: 0,0:03:08.64,0:03:12.42,Default,,0000,0000,0000,,the protein in red blood cells that binds oxygen.
Dialogue: 0,0:03:12.42,0:03:16.06,Default,,0000,0000,0000,,A mutation in a single nucleotide in the gene
Dialogue: 0,0:03:16.06,0:03:19.96,Default,,0000,0000,0000,,causes a single amino acid change in each subunit,
Dialogue: 0,0:03:19.96,0:03:23.14,Default,,0000,0000,0000,,which in turn causes the hemoglobin molecules to
Dialogue: 0,0:03:23.14,0:03:26.74,Default,,0000,0000,0000,,stick together and change the shape of the red blood cells.
Dialogue: 0,0:03:26.74,0:03:28.78,Default,,0000,0000,0000,,DR. ARCHER: Typically, red blood cells have
Dialogue: 0,0:03:28.78,0:03:33.62,Default,,0000,0000,0000,,this disc shape to them that enable them to move throughout the body with ease.
Dialogue: 0,0:03:33.62,0:03:38.46,Default,,0000,0000,0000,,Sickle cell disease makes the red blood cells a little bit more rigid,
Dialogue: 0,0:03:38.46,0:03:43.55,Default,,0000,0000,0000,,so changes the shape and makes it like a crescent moon or sickle shape.
Dialogue: 0,0:03:43.55,0:03:48.57,Default,,0000,0000,0000,,That rigidity of the red blood cell causes them to block blood vessels,
Dialogue: 0,0:03:48.57,0:03:51.55,Default,,0000,0000,0000,,not allowing blood to get to different parts of the body,
Dialogue: 0,0:03:51.55,0:03:54.29,Default,,0000,0000,0000,,causing severe and debilitating pain.
Dialogue: 0,0:03:54.29,0:04:00.92,Default,,0000,0000,0000,,For a pain crisis, my patients typically describe it as a pain that won't go away.
Dialogue: 0,0:04:00.92,0:04:06.26,Default,,0000,0000,0000,,Thinking of your worst pain and not being able to do anything about it, really.
Dialogue: 0,0:04:06.26,0:04:09.31,Default,,0000,0000,0000,,You're doing great. Keep up the good work.
Dialogue: 0,0:04:09.31,0:04:11.09,Default,,0000,0000,0000,,You've taken your medicine,
Dialogue: 0,0:04:11.09,0:04:13.83,Default,,0000,0000,0000,,and I'll see you in 3 months.
Dialogue: 0,0:04:15.74,0:04:20.16,Default,,0000,0000,0000,,MORGAN GRACE: In kindergarten, we had this book.
Dialogue: 0,0:04:20.16,0:04:23.17,Default,,0000,0000,0000,,It's about this young girl with sickle cell,
Dialogue: 0,0:04:23.17,0:04:24.83,Default,,0000,0000,0000,,but she didn't really know what it was.
Dialogue: 0,0:04:24.83,0:04:28.41,Default,,0000,0000,0000,,She just ended up in the hospital quite often.
Dialogue: 0,0:04:28.73,0:04:34.01,Default,,0000,0000,0000,,I could remember having that feeling like I'm in the hospital,
Dialogue: 0,0:04:34.01,0:04:36.33,Default,,0000,0000,0000,,but I don't really know why.
Dialogue: 0,0:04:40.10,0:04:43.60,Default,,0000,0000,0000,,It was really just a lot.
Dialogue: 0,0:04:48.98,0:04:52.16,Default,,0000,0000,0000,,NARRATOR: American researchers first began to study
Dialogue: 0,0:04:52.16,0:04:55.36,Default,,0000,0000,0000,,sickle cell diseases in the early 20th century.
Dialogue: 0,0:04:55.36,0:05:00.58,Default,,0000,0000,0000,,DR. ARCHER: In the US, it was most common among individuals of African ancestry.
Dialogue: 0,0:05:00.58,0:05:05.37,Default,,0000,0000,0000,,They assumed that it was a condition from Africa.
Dialogue: 0,0:05:05.37,0:05:10.06,Default,,0000,0000,0000,,NARRATOR: But no one could explain why sickle cell would be more common in Africa.
Dialogue: 0,0:05:10.06,0:05:12.76,Default,,0000,0000,0000,,Then in the early 1950s,
Dialogue: 0,0:05:12.76,0:05:16.34,Default,,0000,0000,0000,,a Kenyan medical student named Tony Allison made
Dialogue: 0,0:05:16.34,0:05:18.26,Default,,0000,0000,0000,,a surprising discovery while conducting
Dialogue: 0,0:05:18.26,0:05:21.51,Default,,0000,0000,0000,,research on different blood type groups in East Africa.
Dialogue: 0,0:05:21.51,0:05:26.57,Default,,0000,0000,0000,,TONY ALLISON: I actually learned just before going out about the sickle cell condition.
Dialogue: 0,0:05:26.57,0:05:31.08,Default,,0000,0000,0000,,Nobody really knew the frequencies of sickle cells in East Africa.
Dialogue: 0,0:05:31.08,0:05:35.41,Default,,0000,0000,0000,,NARRATOR: Allison wanted to measure the frequencies of the sickle cell allele.
Dialogue: 0,0:05:35.41,0:05:39.07,Default,,0000,0000,0000,,He knew that we inherit 2 copies of most of our genes,
Dialogue: 0,0:05:39.07,0:05:42.31,Default,,0000,0000,0000,,1 from each of our biological parents.
Dialogue: 0,0:05:42.31,0:05:46.95,Default,,0000,0000,0000,,These copies called alleles can be the same or different.
Dialogue: 0,0:05:46.95,0:05:52.41,Default,,0000,0000,0000,,People with 2 copies of the allele without the sickle cell mutation are homozygous,
Dialogue: 0,0:05:52.41,0:05:55.41,Default,,0000,0000,0000,,which means their alleles are the same.
Dialogue: 0,0:05:55.41,0:05:59.59,Default,,0000,0000,0000,,They have round red blood cells and they don't have sickle cell disease.
Dialogue: 0,0:05:59.59,0:06:04.67,Default,,0000,0000,0000,,People with 2 copies of the allele with the mutation are also homozygous,
Dialogue: 0,0:06:04.67,0:06:07.00,Default,,0000,0000,0000,,but for the sickle cell allele.
Dialogue: 0,0:06:07.00,0:06:11.92,Default,,0000,0000,0000,,Many of their red blood cells are sickled and they have sickle cell disease.
Dialogue: 0,0:06:11.92,0:06:16.10,Default,,0000,0000,0000,,People with 1 allele with the sickle cell mutation and 1 allele
Dialogue: 0,0:06:16.10,0:06:22.16,Default,,0000,0000,0000,,without are heterozygous and have what scientists call sickle cell trait.
Dialogue: 0,0:06:22.16,0:06:25.94,Default,,0000,0000,0000,,Under most circumstances, their red blood cells
Dialogue: 0,0:06:25.94,0:06:29.92,Default,,0000,0000,0000,,are round and they don't have any symptoms of the disease.
Dialogue: 0,0:06:29.92,0:06:33.28,Default,,0000,0000,0000,,At the time Tony Allison did his research,
Dialogue: 0,0:06:33.28,0:06:36.60,Default,,0000,0000,0000,,there was no genetic test for sickle cell mutation.
Dialogue: 0,0:06:36.60,0:06:40.94,Default,,0000,0000,0000,,All he could do was look at the blood cells of individuals.
Dialogue: 0,0:06:42.02,0:06:45.47,Default,,0000,0000,0000,,DR. ARCHER: Tony Allison's major challenge
Dialogue: 0,0:06:45.47,0:06:48.77,Default,,0000,0000,0000,,was really trying to identify who were the heterozygous.
Dialogue: 0,0:06:48.77,0:06:52.93,Default,,0000,0000,0000,,It's only in prolonged low oxygen environments
Dialogue: 0,0:06:52.93,0:06:56.14,Default,,0000,0000,0000,,that their blood cells actually become sickled.
Dialogue: 0,0:06:57.08,0:07:01.53,Default,,0000,0000,0000,,Here's the blood of a patient with a sickle cell trait.
Dialogue: 0,0:07:01.53,0:07:05.29,Default,,0000,0000,0000,,They have only 1 sickle cell allele copy.
Dialogue: 0,0:07:05.29,0:07:08.17,Default,,0000,0000,0000,,If you look at this patient's blood under the microscope,
Dialogue: 0,0:07:08.17,0:07:11.59,Default,,0000,0000,0000,,it looks completely normal under normal conditions.
Dialogue: 0,0:07:11.59,0:07:14.75,Default,,0000,0000,0000,,NARRATOR: Researchers can mix a chemical agent to that drop
Dialogue: 0,0:07:14.75,0:07:18.63,Default,,0000,0000,0000,,of blood which creates a low oxygen environment.
Dialogue: 0,0:07:19.00,0:07:21.28,Default,,0000,0000,0000,,After a few hours,
Dialogue: 0,0:07:21.28,0:07:24.00,Default,,0000,0000,0000,,the red blood cells start to sickle.
Dialogue: 0,0:07:24.00,0:07:27.90,Default,,0000,0000,0000,,This allows researchers to distinguish between someone with
Dialogue: 0,0:07:27.90,0:07:32.72,Default,,0000,0000,0000,,no sickle cell alleles and someone with sickle cell trait.
Dialogue: 0,0:07:32.72,0:07:35.76,Default,,0000,0000,0000,,Allison used this simple test to measure
Dialogue: 0,0:07:35.76,0:07:39.78,Default,,0000,0000,0000,,the frequency of sickle cell traits in some parts of Kenya.
Dialogue: 0,0:07:39.78,0:07:43.52,Default,,0000,0000,0000,,TONY ALLISON: You could do it in the field, and I did.
Dialogue: 0,0:07:43.52,0:07:51.02,Default,,0000,0000,0000,,I had a little traveling microscope run off a small bulb that came from a car battery.
Dialogue: 0,0:07:51.02,0:07:54.04,Default,,0000,0000,0000,,NARRATOR: After analyzing hundreds of samples,
Dialogue: 0,0:07:54.04,0:07:57.20,Default,,0000,0000,0000,,an interesting geographic pattern started to emerge.
Dialogue: 0,0:07:57.20,0:08:03.14,Default,,0000,0000,0000,,TONY ALLISON: But what was striking was that you had high frequencies of people carrying
Dialogue: 0,0:08:03.14,0:08:06.44,Default,,0000,0000,0000,,the sickle cell character in the coast and near
Dialogue: 0,0:08:06.44,0:08:11.56,Default,,0000,0000,0000,,Lake Victoria and very low frequencies in the high country in between, in Nairobi.
Dialogue: 0,0:08:11.56,0:08:14.73,Default,,0000,0000,0000,,NARRATOR: In the lowlands,
Dialogue: 0,0:08:14.73,0:08:18.23,Default,,0000,0000,0000,,the sickle cell trait frequencies were over 20 percent.
Dialogue: 0,0:08:18.23,0:08:19.59,Default,,0000,0000,0000,,Whereas in the highlands,
Dialogue: 0,0:08:19.59,0:08:22.93,Default,,0000,0000,0000,,the frequencies were less than 1 percent.
Dialogue: 0,0:08:22.93,0:08:27.77,Default,,0000,0000,0000,,What could explain such dramatic differences between these regions?
Dialogue: 0,0:08:27.77,0:08:31.61,Default,,0000,0000,0000,,A childhood memory helped Tony make the connection.
Dialogue: 0,0:08:31.61,0:08:34.13,Default,,0000,0000,0000,,Allison had caught malaria,
Dialogue: 0,0:08:34.13,0:08:38.93,Default,,0000,0000,0000,,a deadly infectious disease on a family vacation to the Kenyan coast.
Dialogue: 0,0:08:38.93,0:08:42.43,Default,,0000,0000,0000,,He knew very well that the humid lowlands around
Dialogue: 0,0:08:42.43,0:08:46.15,Default,,0000,0000,0000,,Lake Victoria are breeding grounds for the Anopheles mosquito,
Dialogue: 0,0:08:46.15,0:08:49.37,Default,,0000,0000,0000,,which spread the malaria parasite.
Dialogue: 0,0:08:50.21,0:08:54.05,Default,,0000,0000,0000,,Allison also knew that these mosquitoes, and
Dialogue: 0,0:08:54.05,0:08:58.01,Default,,0000,0000,0000,,the malaria they spread, are not common in the drier highlands.
Dialogue: 0,0:08:58.01,0:09:01.96,Default,,0000,0000,0000,,Could sickle cell and malaria somehow be connected?
Dialogue: 0,0:09:01.96,0:09:05.45,Default,,0000,0000,0000,,TONY ALLISON: If that's the case, you predict that you have
Dialogue: 0,0:09:05.45,0:09:10.12,Default,,0000,0000,0000,,high frequencies of sickle cells only in areas where malaria is endemic.
Dialogue: 0,0:09:10.12,0:09:12.19,Default,,0000,0000,0000,,NARRATOR: To test this hypothesis,
Dialogue: 0,0:09:12.19,0:09:16.19,Default,,0000,0000,0000,,Allison needed data from more people and a larger area.
Dialogue: 0,0:09:16.19,0:09:19.97,Default,,0000,0000,0000,,He visited markets and villages throughout Uganda, Kenya,
Dialogue: 0,0:09:19.97,0:09:24.73,Default,,0000,0000,0000,,and Tanzania, offering checkups and medicine to the people in those markets.
Dialogue: 0,0:09:24.73,0:09:30.13,Default,,0000,0000,0000,,During these checkups, he collected about 5,000 blood samples.
Dialogue: 0,0:09:30.13,0:09:34.11,Default,,0000,0000,0000,,The research of Allison and others confirmed that there is
Dialogue: 0,0:09:34.11,0:09:39.48,Default,,0000,0000,0000,,a strong correlation between the frequency of sickle cell trait and malaria.
Dialogue: 0,0:09:39.48,0:09:43.04,Default,,0000,0000,0000,,Tony wondered if having a sickle cell allele
Dialogue: 0,0:09:43.04,0:09:47.32,Default,,0000,0000,0000,,offered an advantage to people living in areas with malaria.
Dialogue: 0,0:09:47.32,0:09:50.40,Default,,0000,0000,0000,,How could he test this hypothesis?
Dialogue: 0,0:09:50.40,0:09:56.16,Default,,0000,0000,0000,,TONY ALLISON: You look at malaria in children of the appropriate age and find out whether they are,
Dialogue: 0,0:09:56.16,0:09:58.46,Default,,0000,0000,0000,,in fact, protected against malaria.
Dialogue: 0,0:09:58.46,0:10:01.70,Default,,0000,0000,0000,,NARRATOR: He collected blood samples from children aged
Dialogue: 0,0:10:01.70,0:10:06.56,Default,,0000,0000,0000,,5 months to 5 years and analyzed them under a microscope.
Dialogue: 0,0:10:06.56,0:10:12.12,Default,,0000,0000,0000,,In each sample, he counted the number of parasites that caused malaria.
Dialogue: 0,0:10:12.12,0:10:15.16,Default,,0000,0000,0000,,He then compared the parasite counts in
Dialogue: 0,0:10:15.16,0:10:19.29,Default,,0000,0000,0000,,children with sickle cell trait to those without.
Dialogue: 0,0:10:21.25,0:10:25.95,Default,,0000,0000,0000,,TONY ALLISON: The sickle cell trait would have lower parasite counts.
Dialogue: 0,0:10:27.07,0:10:31.56,Default,,0000,0000,0000,,NARRATOR: This was the strongest evidence yet that the sickle cell trait
Dialogue: 0,0:10:31.56,0:10:36.27,Default,,0000,0000,0000,,gave heterozygotes an advantage where malaria was present.
Dialogue: 0,0:10:38.23,0:10:41.75,Default,,0000,0000,0000,,People with no sickle cell allele were less
Dialogue: 0,0:10:41.75,0:10:45.66,Default,,0000,0000,0000,,likely to survive and reproduce due to malaria.
Dialogue: 0,0:10:45.97,0:10:50.09,Default,,0000,0000,0000,,People with 2 sickle cell alleles were less likely to
Dialogue: 0,0:10:50.09,0:10:54.18,Default,,0000,0000,0000,,survive and reproduce due to sickle cell disease.
Dialogue: 0,0:10:54.18,0:11:00.18,Default,,0000,0000,0000,,But people with one sickle cell allele were more likely to survive and reproduce.
Dialogue: 0,0:11:00.18,0:11:06.62,Default,,0000,0000,0000,,Tony Allison had discovered the first clear example of natural selection in humans,
Dialogue: 0,0:11:06.62,0:11:11.56,Default,,0000,0000,0000,,but how did the sickle cell allele protect people from malaria?
Dialogue: 0,0:11:11.56,0:11:16.01,Default,,0000,0000,0000,,TONY ALLISON: I have to say, I left that part of this story to
Dialogue: 0,0:11:16.01,0:11:20.97,Default,,0000,0000,0000,,others because it's quite a complex story.
Dialogue: 0,0:11:21.70,0:11:28.30,Default,,0000,0000,0000,,NARRATOR: The parasite that causes malaria feeds on hemoglobin inside red blood cells.
Dialogue: 0,0:11:28.30,0:11:33.23,Default,,0000,0000,0000,,Natasha Archer studies how the sickle cell trait affects this process.
Dialogue: 0,0:11:33.23,0:11:35.10,Default,,0000,0000,0000,,DR. ARCHER: When a mosquito bites you,
Dialogue: 0,0:11:35.10,0:11:38.75,Default,,0000,0000,0000,,the parasite makes its way into the red blood cells.
Dialogue: 0,0:11:38.75,0:11:43.96,Default,,0000,0000,0000,,Eventually, it releases these proteins that attach to
Dialogue: 0,0:11:43.96,0:11:49.25,Default,,0000,0000,0000,,blood vessels and force the red blood cell to stay in one location.
Dialogue: 0,0:11:49.25,0:11:53.04,Default,,0000,0000,0000,,What's unique about the blood vessels that it sticks
Dialogue: 0,0:11:53.04,0:11:57.83,Default,,0000,0000,0000,,to is that those environments typically have low oxygen.
Dialogue: 0,0:11:57.83,0:12:01.31,Default,,0000,0000,0000,,If you remember, individuals with sickle cell trait,
Dialogue: 0,0:12:01.31,0:12:06.74,Default,,0000,0000,0000,,their red blood cells sickle if they are in prolonged low oxygen environments.
Dialogue: 0,0:12:06.74,0:12:13.67,Default,,0000,0000,0000,,The malaria parasite now will not have hemoglobin that's as easily digestible.
Dialogue: 0,0:12:13.67,0:12:16.40,Default,,0000,0000,0000,,NARRATOR: Without hemoglobin to feed on,
Dialogue: 0,0:12:16.40,0:12:20.74,Default,,0000,0000,0000,,malaria parasites can't grow or reproduce as quickly.
Dialogue: 0,0:12:20.74,0:12:25.07,Default,,0000,0000,0000,,DR. ARCHER: Our research takes us one step further in understanding
Dialogue: 0,0:12:25.07,0:12:30.30,Default,,0000,0000,0000,,how sickle cell trait is protective against malaria.
Dialogue: 0,0:12:30.30,0:12:35.03,Default,,0000,0000,0000,,NARRATOR: Malaria occurred in many regions around the world.
Dialogue: 0,0:12:35.03,0:12:43.05,Default,,0000,0000,0000,,Does the pattern Tony Allison observed in East Africa also occur in these other regions?
Dialogue: 0,0:12:48.97,0:12:54.32,Default,,0000,0000,0000,,MATHEW GLARUM: What I love about playing music is that when I am up there playing,
Dialogue: 0,0:12:54.32,0:12:56.99,Default,,0000,0000,0000,,there's nothing but that. That's my therapy.
Dialogue: 0,0:12:56.99,0:13:05.69,Default,,0000,0000,0000,,'Cause I can’t hold her anymore. Can’t pass the time.
Dialogue: 0,0:13:05.69,0:13:10.67,Default,,0000,0000,0000,,According to my grandma, I was begging her for guitar lessons at 5-years-old.
Dialogue: 0,0:13:10.67,0:13:14.34,Default,,0000,0000,0000,,It's always been around in my life, instruments and stuff.
Dialogue: 0,0:13:26.23,0:13:28.56,Default,,0000,0000,0000,,When I was born,
Dialogue: 0,0:13:28.56,0:13:31.64,Default,,0000,0000,0000,,my mom knew to look out for us
Dialogue: 0,0:13:31.64,0:13:36.78,Default,,0000,0000,0000,,potentially having sickle cell because my brother,
Dialogue: 0,0:13:36.78,0:13:39.06,Default,,0000,0000,0000,,he was born with it.
Dialogue: 0,0:13:41.98,0:13:47.00,Default,,0000,0000,0000,,When you're a kid and all you want to do is have fun with your friends,
Dialogue: 0,0:13:47.00,0:13:50.79,Default,,0000,0000,0000,,we could get pain, get taken to the hospital.
Dialogue: 0,0:13:54.61,0:13:58.22,Default,,0000,0000,0000,,We couldn't participate in holidays,
Dialogue: 0,0:13:58.22,0:14:01.98,Default,,0000,0000,0000,,family vacations, and we couldn't go to school.
Dialogue: 0,0:14:01.98,0:14:04.31,Default,,0000,0000,0000,,That gets in the way a little bit.
Dialogue: 0,0:14:04.31,0:14:08.22,Default,,0000,0000,0000,,Now, as an adult, I've had experiences where my sickle cell
Dialogue: 0,0:14:08.22,0:14:12.87,Default,,0000,0000,0000,,and getting into a crisis has messed up important stuff.
Dialogue: 0,0:14:13.54,0:14:19.66,Default,,0000,0000,0000,,My mom's part of the family comes from the Mediterranean area in Sicily.
Dialogue: 0,0:14:19.66,0:14:23.97,Default,,0000,0000,0000,,Then my dad is from Norway and then Belize.
Dialogue: 0,0:14:24.16,0:14:27.83,Default,,0000,0000,0000,,DR. ARCHER: When we look at the people who carry the sickle cell allele,
Dialogue: 0,0:14:27.83,0:14:31.82,Default,,0000,0000,0000,,they share recent ancestry with regions that have historically experienced
Dialogue: 0,0:14:31.82,0:14:36.94,Default,,0000,0000,0000,,high rates of malaria like sub Saharan Africa, Greece, Italy.
Dialogue: 0,0:14:36.94,0:14:40.26,Default,,0000,0000,0000,,NARRATOR: Several studies have shown that throughout the world,
Dialogue: 0,0:14:40.26,0:14:44.36,Default,,0000,0000,0000,,the frequency of the sickle cell allele tends to be lower in areas with
Dialogue: 0,0:14:44.36,0:14:49.06,Default,,0000,0000,0000,,little to no malaria and higher in areas with a lot of malaria,
Dialogue: 0,0:14:49.06,0:14:53.63,Default,,0000,0000,0000,,similar to what Tony Allison and other researchers observed in Africa.
Dialogue: 0,0:14:53.63,0:14:57.05,Default,,0000,0000,0000,,Scientists have observed similar patterns with
Dialogue: 0,0:14:57.05,0:15:01.50,Default,,0000,0000,0000,,other inherited conditions that affect red blood cells.
Dialogue: 0,0:15:01.63,0:15:05.34,Default,,0000,0000,0000,,DR. ARCHER: I also treat patients who have mutations in other genes,
Dialogue: 0,0:15:05.34,0:15:07.80,Default,,0000,0000,0000,,which cause diseases like ovalcytosis,
Dialogue: 0,0:15:07.80,0:15:12.18,Default,,0000,0000,0000,,Thalassemia, G6PD enzyme deficiency and others.
Dialogue: 0,0:15:12.18,0:15:18.04,Default,,0000,0000,0000,,NARRATOR: Mutations in these genes also make it harder for the malaria parasite to infect,
Dialogue: 0,0:15:18.04,0:15:22.13,Default,,0000,0000,0000,,survive, or reproduce in red blood cells.
Dialogue: 0,0:15:22.13,0:15:24.47,Default,,0000,0000,0000,,DR. ARCHER: Just like the sickle cell allele,
Dialogue: 0,0:15:24.47,0:15:29.82,Default,,0000,0000,0000,,all of the alleles causing these other disorders are found in high frequencies in people
Dialogue: 0,0:15:29.82,0:15:35.21,Default,,0000,0000,0000,,with ancestors from parts of the world that have historically had high rates of malaria,
Dialogue: 0,0:15:35.21,0:15:41.08,Default,,0000,0000,0000,,but are extremely rare among people without ancestry from those areas.
Dialogue: 0,0:15:41.08,0:15:43.19,Default,,0000,0000,0000,,NARRATOR: In evolutionary terms,
Dialogue: 0,0:15:43.19,0:15:46.37,Default,,0000,0000,0000,,these differences in allele frequencies reflect that
Dialogue: 0,0:15:46.37,0:15:50.75,Default,,0000,0000,0000,,specific mutations in these genes confer a net advantage
Dialogue: 0,0:15:50.75,0:15:54.50,Default,,0000,0000,0000,,in areas with high incidence of malaria and are
Dialogue: 0,0:15:54.50,0:15:58.96,Default,,0000,0000,0000,,favored by natural selection over generations in a population,
Dialogue: 0,0:15:58.96,0:16:02.36,Default,,0000,0000,0000,,whereas they confer a disadvantage and are disfavored
Dialogue: 0,0:16:02.36,0:16:06.32,Default,,0000,0000,0000,,by natural selection in environments without malaria.
Dialogue: 0,0:16:06.32,0:16:12.15,Default,,0000,0000,0000,,DR. ARCHER: It's clear that malaria has had a profound effect on human biology.
Dialogue: 0,0:16:17.71,0:16:20.87,Default,,0000,0000,0000,,MATHEW GLARUM: Right now, I'm in nursing school,
Dialogue: 0,0:16:20.87,0:16:24.74,Default,,0000,0000,0000,,so I'll be graduating as a nurse at the end of this year.
Dialogue: 0,0:16:24.74,0:16:28.28,Default,,0000,0000,0000,,I think it will be beneficial for me,
Dialogue: 0,0:16:28.28,0:16:29.51,Default,,0000,0000,0000,,especially as a nurse,
Dialogue: 0,0:16:29.51,0:16:33.06,Default,,0000,0000,0000,,knowing what it's like to be in that hospital bed.
Dialogue: 0,0:16:39.37,0:16:43.44,Default,,0000,0000,0000,,DR. ARCHER: Hey, Morgan, I'm ready for you.
Dialogue: 0,0:16:46.45,0:16:51.22,Default,,0000,0000,0000,,MORGAN GRACE: I don't let having sickle cell stop me at all.
Dialogue: 0,0:16:51.22,0:16:53.56,Default,,0000,0000,0000,,I'm still going to do the things that I want to do.
Dialogue: 0,0:16:53.56,0:16:55.90,Default,,0000,0000,0000,,I might just do it with extra precaution.
Dialogue: 0,0:16:55.90,0:16:59.80,Default,,0000,0000,0000,,I think it's made me a really more determined person.
Dialogue: 0,0:16:59.80,0:17:04.18,Default,,0000,0000,0000,,It doesn't matter if I have a week-long hospital stay,
Dialogue: 0,0:17:04.18,0:17:09.21,Default,,0000,0000,0000,,I just need to get it done and do the best that I can.
Dialogue: 0,0:17:09.67,0:17:12.77,Default,,0000,0000,0000,,DR. ARCHER: So tell me how you're feeling?
Dialogue: 0,0:17:12.77,0:17:15.05,Default,,0000,0000,0000,,MORGAN GRACE: I'm feeling pretty good.
Dialogue: 0,0:17:15.05,0:17:17.32,Default,,0000,0000,0000,,DR. ARCHER: When I talk to my patients,
Dialogue: 0,0:17:17.32,0:17:19.48,Default,,0000,0000,0000,,I start by discussing the biology.
Dialogue: 0,0:17:19.48,0:17:23.34,Default,,0000,0000,0000,,They inherited these genes and that
Dialogue: 0,0:17:23.34,0:17:28.58,Default,,0000,0000,0000,,they are part of fighting this global threat, which was malaria.
Dialogue: 0,0:17:28.58,0:17:32.21,Default,,0000,0000,0000,,Science has helped us understand sickle cell disease,
Dialogue: 0,0:17:32.21,0:17:35.13,Default,,0000,0000,0000,,and it's the only thing that's going to help us cure it.
Dialogue: 0,0:17:35.80,0:17:40.79,Default,,0000,0000,0000,,I am very confident that we will eventually tackle this problem.
Dialogue: 0,0:17:40.79,0:17:42.59,Default,,0000,0000,0000,,I'll see you in a couple of months.
Dialogue: 0,0:17:42.59,0:17:47.21,Default,,0000,0000,0000,,Don't forget to schedule your visit and call me if you need me, okay?
Dialogue: 0,0:17:47.21,0:18:27.24,Default,,0000,0000,0000,,Alright, bye!