[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:01.12,0:00:05.15,Default,,0000,0000,0000,,When I was approximately\Nnine weeks pregnant with my first child,
Dialogue: 0,0:00:05.18,0:00:08.65,Default,,0000,0000,0000,,I found out I'm a carrier\Nfor a fatal genetic disorder
Dialogue: 0,0:00:08.68,0:00:10.34,Default,,0000,0000,0000,,called Tay-Sachs disease.
Dialogue: 0,0:00:11.10,0:00:12.29,Default,,0000,0000,0000,,What this means
Dialogue: 0,0:00:12.32,0:00:16.20,Default,,0000,0000,0000,,is that one of the two copies\Nof chromosome number 15
Dialogue: 0,0:00:16.23,0:00:18.14,Default,,0000,0000,0000,,that I have in each of my cells
Dialogue: 0,0:00:18.16,0:00:19.81,Default,,0000,0000,0000,,has a genetic mutation.
Dialogue: 0,0:00:20.46,0:00:23.49,Default,,0000,0000,0000,,Because I still have\None normal copy of this gene,
Dialogue: 0,0:00:23.51,0:00:25.58,Default,,0000,0000,0000,,the mutation doesn't affect me.
Dialogue: 0,0:00:26.06,0:00:29.90,Default,,0000,0000,0000,,But if a baby inherits this mutation\Nfrom both parents,
Dialogue: 0,0:00:29.93,0:00:34.24,Default,,0000,0000,0000,,if both copies of this particular gene\Ndon't function properly,
Dialogue: 0,0:00:34.26,0:00:36.06,Default,,0000,0000,0000,,it results in Tay-Sachs,
Dialogue: 0,0:00:36.08,0:00:37.93,Default,,0000,0000,0000,,an incurable disease
Dialogue: 0,0:00:37.96,0:00:40.70,Default,,0000,0000,0000,,that progressively shuts down\Nthe central nervous system
Dialogue: 0,0:00:40.73,0:00:43.12,Default,,0000,0000,0000,,and causes death by age five.
Dialogue: 0,0:00:44.57,0:00:48.80,Default,,0000,0000,0000,,For many pregnant women,\Nthis news might produce a full-on panic.
Dialogue: 0,0:00:49.12,0:00:51.48,Default,,0000,0000,0000,,But I knew something\Nthat helped keep me calm
Dialogue: 0,0:00:51.50,0:00:54.62,Default,,0000,0000,0000,,when I heard this bombshell\Nabout my own biology.
Dialogue: 0,0:00:54.94,0:00:56.36,Default,,0000,0000,0000,,I knew that my husband,
Dialogue: 0,0:00:56.39,0:01:00.09,Default,,0000,0000,0000,,whose ancestry isn't Eastern\NEuropean Jewish like mine,
Dialogue: 0,0:01:00.11,0:01:01.77,Default,,0000,0000,0000,,had a very low likelihood
Dialogue: 0,0:01:01.79,0:01:05.11,Default,,0000,0000,0000,,of also being a carrier\Nfor the Tay-Sachs mutation.
Dialogue: 0,0:01:05.57,0:01:07.86,Default,,0000,0000,0000,,While the frequency of heterozygotes,
Dialogue: 0,0:01:07.89,0:01:10.66,Default,,0000,0000,0000,,individuals who have\None normal copy of the gene
Dialogue: 0,0:01:10.68,0:01:12.35,Default,,0000,0000,0000,,and one mutated copy,
Dialogue: 0,0:01:12.37,0:01:18.36,Default,,0000,0000,0000,,is about one out of 27 people\Namong Jews of Ashkenazi descent, like me,
Dialogue: 0,0:01:18.38,0:01:20.01,Default,,0000,0000,0000,,in most populations,
Dialogue: 0,0:01:20.04,0:01:24.28,Default,,0000,0000,0000,,only one in about 300 people\Ncarry the Tay-Sachs mutation.
Dialogue: 0,0:01:25.12,0:01:28.36,Default,,0000,0000,0000,,Thankfully, it turned out I was right\Nnot to worry too much.
Dialogue: 0,0:01:28.39,0:01:30.12,Default,,0000,0000,0000,,My husband isn't a carrier,
Dialogue: 0,0:01:30.14,0:01:33.32,Default,,0000,0000,0000,,and we now have two beautiful\Nand healthy children.
Dialogue: 0,0:01:35.60,0:01:36.75,Default,,0000,0000,0000,,As I said,
Dialogue: 0,0:01:36.78,0:01:38.31,Default,,0000,0000,0000,,because of my Jewish background,
Dialogue: 0,0:01:38.33,0:01:43.50,Default,,0000,0000,0000,,I was aware of the unusually high rate\Nof Tay-Sachs in the Ashkenazi population.
Dialogue: 0,0:01:43.52,0:01:47.14,Default,,0000,0000,0000,,But it wasn't until a few years\Nafter my daughter was born
Dialogue: 0,0:01:47.16,0:01:51.21,Default,,0000,0000,0000,,when I created and taught a seminar\Nin evolutionary medicine at Harvard,
Dialogue: 0,0:01:51.24,0:01:52.83,Default,,0000,0000,0000,,that I thought to ask,
Dialogue: 0,0:01:52.86,0:01:55.22,Default,,0000,0000,0000,,and discovered a possible answer to,
Dialogue: 0,0:01:55.24,0:01:56.89,Default,,0000,0000,0000,,the question "why?"
Dialogue: 0,0:01:57.25,0:01:59.74,Default,,0000,0000,0000,,The process of evolution\Nby natural selection
Dialogue: 0,0:01:59.77,0:02:02.43,Default,,0000,0000,0000,,typically eliminates harmful mutations.
Dialogue: 0,0:02:02.78,0:02:06.33,Default,,0000,0000,0000,,So how did this defective gene\Npersist at all?
Dialogue: 0,0:02:06.35,0:02:09.41,Default,,0000,0000,0000,,And why is it found\Nat such a high frequency
Dialogue: 0,0:02:09.43,0:02:11.70,Default,,0000,0000,0000,,within this particular population?
Dialogue: 0,0:02:13.06,0:02:17.09,Default,,0000,0000,0000,,The perspective of evolutionary medicine\Noffers valuable insight,
Dialogue: 0,0:02:17.12,0:02:19.52,Default,,0000,0000,0000,,because it examines how and why
Dialogue: 0,0:02:19.55,0:02:23.44,Default,,0000,0000,0000,,humans' evolutionary past\Nhas left our bodies vulnerable
Dialogue: 0,0:02:23.47,0:02:26.06,Default,,0000,0000,0000,,to diseases and other problems today.
Dialogue: 0,0:02:26.72,0:02:28.06,Default,,0000,0000,0000,,In doing so,
Dialogue: 0,0:02:28.08,0:02:32.27,Default,,0000,0000,0000,,it demonstrates that natural selection\Ndoesn't always make our bodies better.
Dialogue: 0,0:02:32.30,0:02:34.02,Default,,0000,0000,0000,,It can't necessarily.
Dialogue: 0,0:02:34.60,0:02:37.39,Default,,0000,0000,0000,,But as I hope to illustrate\Nwith my own story,
Dialogue: 0,0:02:37.42,0:02:40.93,Default,,0000,0000,0000,,understanding the implications\Nof your evolutionary past
Dialogue: 0,0:02:40.96,0:02:43.84,Default,,0000,0000,0000,,can help enrich your personal health.
Dialogue: 0,0:02:45.15,0:02:49.08,Default,,0000,0000,0000,,When I started investigating Tay-Sachs\Nusing an evolutionary perspective,
Dialogue: 0,0:02:49.10,0:02:52.01,Default,,0000,0000,0000,,I came across an intriguing hypothesis.
Dialogue: 0,0:02:52.40,0:02:55.34,Default,,0000,0000,0000,,The unusually high rate\Nof the Tay-Sachs mutation
Dialogue: 0,0:02:55.36,0:02:57.70,Default,,0000,0000,0000,,in Ashkenazi Jews today
Dialogue: 0,0:02:57.73,0:03:01.56,Default,,0000,0000,0000,,may relate to advantages\Nthe mutation gave this population
Dialogue: 0,0:03:01.58,0:03:02.74,Default,,0000,0000,0000,,in the past.
Dialogue: 0,0:03:03.66,0:03:05.51,Default,,0000,0000,0000,,Now I'm sure some of you are thinking,
Dialogue: 0,0:03:05.53,0:03:09.50,Default,,0000,0000,0000,,"I'm sorry, did you just suggest\Nthat this disease-causing mutation
Dialogue: 0,0:03:09.52,0:03:11.73,Default,,0000,0000,0000,,had beneficial effects?"
Dialogue: 0,0:03:11.75,0:03:13.15,Default,,0000,0000,0000,,Yeah, I did.
Dialogue: 0,0:03:13.17,0:03:16.82,Default,,0000,0000,0000,,Certainly not for individuals\Nwho inherited two copies of the mutation
Dialogue: 0,0:03:16.85,0:03:18.47,Default,,0000,0000,0000,,and had Tay-Sachs.
Dialogue: 0,0:03:18.85,0:03:20.77,Default,,0000,0000,0000,,But under certain circumstances,
Dialogue: 0,0:03:20.79,0:03:21.96,Default,,0000,0000,0000,,people like me,
Dialogue: 0,0:03:21.98,0:03:25.11,Default,,0000,0000,0000,,who had only one faulty gene copy,
Dialogue: 0,0:03:25.13,0:03:29.00,Default,,0000,0000,0000,,may have been more likely\Nto survive, reproduce
Dialogue: 0,0:03:29.03,0:03:31.26,Default,,0000,0000,0000,,and pass on their genetic material,
Dialogue: 0,0:03:31.28,0:03:33.25,Default,,0000,0000,0000,,including that mutated gene.
Dialogue: 0,0:03:34.63,0:03:40.42,Default,,0000,0000,0000,,This idea that there can be circumstances\Nin which heterozygotes are better off
Dialogue: 0,0:03:40.45,0:03:42.77,Default,,0000,0000,0000,,might sound familiar to some of you.
Dialogue: 0,0:03:43.08,0:03:45.97,Default,,0000,0000,0000,,Evolutionary biologists\Ncall this phenomenon
Dialogue: 0,0:03:45.99,0:03:48.26,Default,,0000,0000,0000,,heterozygote advantage.
Dialogue: 0,0:03:48.28,0:03:50.88,Default,,0000,0000,0000,,And it explains, for example,
Dialogue: 0,0:03:50.90,0:03:52.90,Default,,0000,0000,0000,,why carriers of sickle cell anemia
Dialogue: 0,0:03:52.92,0:03:56.94,Default,,0000,0000,0000,,are more common among\Nsome African and Asian populations
Dialogue: 0,0:03:56.97,0:04:00.10,Default,,0000,0000,0000,,or those with ancestry\Nfrom these tropical regions.
Dialogue: 0,0:04:00.77,0:04:05.79,Default,,0000,0000,0000,,In these geographic regions,\Nmalaria poses significant risks to health.
Dialogue: 0,0:04:06.55,0:04:09.16,Default,,0000,0000,0000,,The parasite that causes malaria, though,
Dialogue: 0,0:04:09.19,0:04:14.69,Default,,0000,0000,0000,,can only complete its life cycle\Nin normal, round red blood cells.
Dialogue: 0,0:04:15.49,0:04:18.55,Default,,0000,0000,0000,,By changing the shape\Nof a person's red blood cells,
Dialogue: 0,0:04:18.57,0:04:22.86,Default,,0000,0000,0000,,the sickle cell mutation\Nconfers protection against malaria.
Dialogue: 0,0:04:23.66,0:04:26.52,Default,,0000,0000,0000,,People with the mutation\Naren't less likely to get bitten
Dialogue: 0,0:04:26.54,0:04:29.04,Default,,0000,0000,0000,,by the mosquitoes\Nthat transmit the disease,
Dialogue: 0,0:04:29.07,0:04:32.70,Default,,0000,0000,0000,,but they are less likely to get sick\Nor die as a result.
Dialogue: 0,0:04:33.45,0:04:36.20,Default,,0000,0000,0000,,Being a carrier for sickle cell anemia
Dialogue: 0,0:04:36.23,0:04:39.11,Default,,0000,0000,0000,,is therefore the best\Npossible genetic option
Dialogue: 0,0:04:39.13,0:04:40.87,Default,,0000,0000,0000,,in a malarial environment.
Dialogue: 0,0:04:41.28,0:04:43.65,Default,,0000,0000,0000,,Carriers are less susceptible to malaria,
Dialogue: 0,0:04:43.68,0:04:46.64,Default,,0000,0000,0000,,because they make some\Nsickled red blood cells,
Dialogue: 0,0:04:46.66,0:04:49.51,Default,,0000,0000,0000,,but they make enough\Nnormal red blood cells
Dialogue: 0,0:04:49.54,0:04:53.16,Default,,0000,0000,0000,,that they aren't negatively affected\Nby sickle cell anemia.
Dialogue: 0,0:04:55.29,0:04:56.45,Default,,0000,0000,0000,,Now in my case,
Dialogue: 0,0:04:56.47,0:05:00.45,Default,,0000,0000,0000,,the defective gene I carry\Nwon't protect me against malaria.
Dialogue: 0,0:05:01.20,0:05:04.90,Default,,0000,0000,0000,,But the unusual prevalence\Nof the Tay-Sachs mutation
Dialogue: 0,0:05:04.93,0:05:06.80,Default,,0000,0000,0000,,in Ashkenazi populations
Dialogue: 0,0:05:06.82,0:05:10.76,Default,,0000,0000,0000,,may be another example\Nof heterozygote advantage.
Dialogue: 0,0:05:10.78,0:05:14.31,Default,,0000,0000,0000,,In this case, increasing\Nresistance to tuberculosis.
Dialogue: 0,0:05:15.92,0:05:20.48,Default,,0000,0000,0000,,The first hint of a possible relationship\Nbetween Tay-Sachs and tuberculosis
Dialogue: 0,0:05:20.50,0:05:22.46,Default,,0000,0000,0000,,came in the 1970s,
Dialogue: 0,0:05:22.48,0:05:23.97,Default,,0000,0000,0000,,when researchers published data
Dialogue: 0,0:05:23.100,0:05:27.03,Default,,0000,0000,0000,,showing that among\Nthe Eastern European-born grandparents
Dialogue: 0,0:05:27.05,0:05:31.20,Default,,0000,0000,0000,,of a sample of American Ashkenazi\Nchildren born with Tay-Sachs,
Dialogue: 0,0:05:31.22,0:05:35.02,Default,,0000,0000,0000,,tuberculosis was an exceedingly\Nrare cause of death.
Dialogue: 0,0:05:35.04,0:05:39.15,Default,,0000,0000,0000,,In fact, only one\Nout of these 306 grandparents
Dialogue: 0,0:05:39.18,0:05:41.02,Default,,0000,0000,0000,,had died of TB,
Dialogue: 0,0:05:41.04,0:05:44.18,Default,,0000,0000,0000,,despite the fact\Nthat in the early 20th century,
Dialogue: 0,0:05:44.20,0:05:49.02,Default,,0000,0000,0000,,TB caused up to 20 percent of deaths\Nin large Eastern European cities.
Dialogue: 0,0:05:50.48,0:05:53.16,Default,,0000,0000,0000,,Now on the one hand,\Nthese results weren't surprising.
Dialogue: 0,0:05:53.18,0:05:54.91,Default,,0000,0000,0000,,People had already recognized
Dialogue: 0,0:05:54.94,0:05:57.40,Default,,0000,0000,0000,,that while Jews and non-Jews in Europe
Dialogue: 0,0:05:57.43,0:06:01.15,Default,,0000,0000,0000,,had been equally likely\Nto contract TB during this time,
Dialogue: 0,0:06:01.17,0:06:04.79,Default,,0000,0000,0000,,the death rate among non-Jews\Nwas twice as high.
Dialogue: 0,0:06:05.66,0:06:08.83,Default,,0000,0000,0000,,But the hypothesis\Nthat these Ashkenazi grandparents
Dialogue: 0,0:06:08.86,0:06:11.39,Default,,0000,0000,0000,,had been less likely to die of TB
Dialogue: 0,0:06:11.41,0:06:16.00,Default,,0000,0000,0000,,specifically because at least some of them\Nwere Tay-Sachs carriers
Dialogue: 0,0:06:16.03,0:06:17.95,Default,,0000,0000,0000,,was novel and compelling.
Dialogue: 0,0:06:18.54,0:06:19.70,Default,,0000,0000,0000,,The data hinted
Dialogue: 0,0:06:19.72,0:06:21.89,Default,,0000,0000,0000,,that the persistence\Nof the Tay-Sachs mutation
Dialogue: 0,0:06:21.91,0:06:23.62,Default,,0000,0000,0000,,among Ashkenazi Jews
Dialogue: 0,0:06:23.64,0:06:27.24,Default,,0000,0000,0000,,might be explained by the benefits\Nof being a carrier
Dialogue: 0,0:06:27.26,0:06:30.84,Default,,0000,0000,0000,,in an environment\Nwhere tuberculosis was prevalent.
Dialogue: 0,0:06:32.14,0:06:33.49,Default,,0000,0000,0000,,You'll notice, though,
Dialogue: 0,0:06:33.52,0:06:37.21,Default,,0000,0000,0000,,that this explanation\Nonly fills in part of the puzzle.
Dialogue: 0,0:06:37.80,0:06:40.98,Default,,0000,0000,0000,,Even if the Tay-Sachs mutation persisted
Dialogue: 0,0:06:41.01,0:06:43.57,Default,,0000,0000,0000,,because carriers\Nwere more likely to survive,
Dialogue: 0,0:06:43.60,0:06:46.77,Default,,0000,0000,0000,,reproduce and pass on\Ntheir genetic material,
Dialogue: 0,0:06:46.80,0:06:49.44,Default,,0000,0000,0000,,why did this resistance\Nmechanism proliferate
Dialogue: 0,0:06:49.47,0:06:52.53,Default,,0000,0000,0000,,among the Ashkenazi\Npopulation in particular?
Dialogue: 0,0:06:53.63,0:06:58.74,Default,,0000,0000,0000,,One possibility is that the genes\Nand health of Eastern European Jews
Dialogue: 0,0:06:58.77,0:07:01.52,Default,,0000,0000,0000,,were affected not simply by geography
Dialogue: 0,0:07:01.54,0:07:04.90,Default,,0000,0000,0000,,but also by historical\Nand cultural factors.
Dialogue: 0,0:07:05.59,0:07:07.30,Default,,0000,0000,0000,,At various points in history
Dialogue: 0,0:07:07.33,0:07:10.91,Default,,0000,0000,0000,,this population was forced to live\Nin crowded urban ghettos
Dialogue: 0,0:07:10.93,0:07:12.33,Default,,0000,0000,0000,,with poor sanitation.
Dialogue: 0,0:07:12.69,0:07:16.70,Default,,0000,0000,0000,,Ideal conditions for the tuberculosis\Nbacterium to thrive.
Dialogue: 0,0:07:17.28,0:07:21.82,Default,,0000,0000,0000,,In these environments,\Nwhere TB posed an especially high threat,
Dialogue: 0,0:07:21.85,0:07:26.65,Default,,0000,0000,0000,,those individuals who were not carriers\Nof any genetic protection
Dialogue: 0,0:07:26.67,0:07:29.01,Default,,0000,0000,0000,,would have been more likely to die.
Dialogue: 0,0:07:29.48,0:07:31.53,Default,,0000,0000,0000,,This winnowing effect
Dialogue: 0,0:07:31.55,0:07:34.52,Default,,0000,0000,0000,,together with a strong\Ncultural predilection
Dialogue: 0,0:07:34.55,0:07:38.88,Default,,0000,0000,0000,,for marrying and reproducing\Nonly within the Ashkenazi community,
Dialogue: 0,0:07:38.90,0:07:42.62,Default,,0000,0000,0000,,would have amplified\Nthe relative frequency of carriers,
Dialogue: 0,0:07:42.65,0:07:44.61,Default,,0000,0000,0000,,boosting TB resistance
Dialogue: 0,0:07:44.63,0:07:49.43,Default,,0000,0000,0000,,but increasing the incidence of Tay-Sachs\Nas an unfortunate side effect.
Dialogue: 0,0:07:50.40,0:07:53.15,Default,,0000,0000,0000,,Studies from the 1980s support this idea.
Dialogue: 0,0:07:53.71,0:07:56.33,Default,,0000,0000,0000,,The segment of the American\NJewish population
Dialogue: 0,0:07:56.36,0:07:59.50,Default,,0000,0000,0000,,that had the highest frequency\Nof Tay-Sachs carriers
Dialogue: 0,0:07:59.52,0:08:01.04,Default,,0000,0000,0000,,traced their descent
Dialogue: 0,0:08:01.06,0:08:05.10,Default,,0000,0000,0000,,to those European countries\Nwhere the incidence of TB was highest.
Dialogue: 0,0:08:05.68,0:08:09.28,Default,,0000,0000,0000,,The benefits of being\Na Tay-Sachs carrier were highest
Dialogue: 0,0:08:09.30,0:08:13.09,Default,,0000,0000,0000,,in those places where the risk\Nof death due to TB was greatest.
Dialogue: 0,0:08:13.56,0:08:16.74,Default,,0000,0000,0000,,And while it was unclear\Nin the 1970s or '80s
Dialogue: 0,0:08:16.77,0:08:21.95,Default,,0000,0000,0000,,how exactly the Tay-Sachs mutation\Noffered protection against TB,
Dialogue: 0,0:08:21.97,0:08:23.76,Default,,0000,0000,0000,,recent work has identified
Dialogue: 0,0:08:23.78,0:08:27.82,Default,,0000,0000,0000,,how the mutation increases\Ncellular defenses against the bacterium.
Dialogue: 0,0:08:29.32,0:08:32.62,Default,,0000,0000,0000,,So heterozygote advantage can help explain
Dialogue: 0,0:08:32.65,0:08:36.40,Default,,0000,0000,0000,,why problematic versions of genes\Npersist at high frequencies
Dialogue: 0,0:08:36.42,0:08:37.95,Default,,0000,0000,0000,,in certain populations.
Dialogue: 0,0:08:38.48,0:08:41.93,Default,,0000,0000,0000,,But this is only one of the contributions\Nevolutionary medicine can make
Dialogue: 0,0:08:41.96,0:08:44.11,Default,,0000,0000,0000,,in helping us understand human health.
Dialogue: 0,0:08:44.69,0:08:46.05,Default,,0000,0000,0000,,As I mentioned earlier,
Dialogue: 0,0:08:46.08,0:08:48.00,Default,,0000,0000,0000,,this field challenges the notion
Dialogue: 0,0:08:48.03,0:08:51.05,Default,,0000,0000,0000,,that our bodies should have gotten\Nbetter over time.
Dialogue: 0,0:08:51.08,0:08:54.17,Default,,0000,0000,0000,,An idea that often stems\Nfrom a misconception
Dialogue: 0,0:08:54.20,0:08:56.35,Default,,0000,0000,0000,,of how evolution works.
Dialogue: 0,0:08:57.36,0:08:58.54,Default,,0000,0000,0000,,In a nutshell,
Dialogue: 0,0:08:58.56,0:09:01.23,Default,,0000,0000,0000,,there are three basic reasons\Nwhy human bodies,
Dialogue: 0,0:09:01.25,0:09:03.24,Default,,0000,0000,0000,,including yours and mine,
Dialogue: 0,0:09:03.26,0:09:06.94,Default,,0000,0000,0000,,remain vulnerable to diseases\Nand other health problems today.
Dialogue: 0,0:09:07.38,0:09:09.56,Default,,0000,0000,0000,,Natural selection acts slowly,
Dialogue: 0,0:09:09.58,0:09:12.29,Default,,0000,0000,0000,,there are limitations\Nto the changes it can make
Dialogue: 0,0:09:12.32,0:09:15.45,Default,,0000,0000,0000,,and it optimizes for reproductive success,
Dialogue: 0,0:09:15.47,0:09:17.11,Default,,0000,0000,0000,,not health.
Dialogue: 0,0:09:18.64,0:09:21.80,Default,,0000,0000,0000,,The way the pace of natural selection\Naffects human health
Dialogue: 0,0:09:21.82,0:09:23.54,Default,,0000,0000,0000,,is probably most obvious
Dialogue: 0,0:09:23.56,0:09:26.93,Default,,0000,0000,0000,,in people's relationship\Nwith infectious pathogens.
Dialogue: 0,0:09:26.96,0:09:31.29,Default,,0000,0000,0000,,We're in a constant arms race\Nwith bacteria and viruses.
Dialogue: 0,0:09:31.31,0:09:36.18,Default,,0000,0000,0000,,Our immune system is continuously evolving\Nto limit their ability to infect,
Dialogue: 0,0:09:36.21,0:09:40.78,Default,,0000,0000,0000,,and they are continuously developing ways\Nto outmaneuver our defenses.
Dialogue: 0,0:09:40.80,0:09:43.82,Default,,0000,0000,0000,,And our species\Nis at a distinct disadvantage
Dialogue: 0,0:09:43.84,0:09:46.84,Default,,0000,0000,0000,,due to our long lives\Nand slow reproduction.
Dialogue: 0,0:09:47.42,0:09:52.01,Default,,0000,0000,0000,,In the time it takes us\Nto evolve one mechanism of resistance,
Dialogue: 0,0:09:52.04,0:09:56.14,Default,,0000,0000,0000,,a pathogenic species\Nwill go through millions of generations,
Dialogue: 0,0:09:56.16,0:09:58.05,Default,,0000,0000,0000,,giving it ample time to evolve,
Dialogue: 0,0:09:58.08,0:10:00.84,Default,,0000,0000,0000,,so it can continue\Nusing our bodies as a host.
Dialogue: 0,0:10:02.48,0:10:04.75,Default,,0000,0000,0000,,Now what does it mean\Nthat there are limitations
Dialogue: 0,0:10:04.78,0:10:07.10,Default,,0000,0000,0000,,to the changes natural selection can make?
Dialogue: 0,0:10:07.12,0:10:09.96,Default,,0000,0000,0000,,Again, my examples\Nof heterozygote advantage
Dialogue: 0,0:10:09.99,0:10:11.86,Default,,0000,0000,0000,,offer a useful illustration.
Dialogue: 0,0:10:12.51,0:10:15.37,Default,,0000,0000,0000,,In terms of resisting TB and malaria,
Dialogue: 0,0:10:15.40,0:10:19.99,Default,,0000,0000,0000,,the physiological effects of the Tay-Sachs\Nand sickle cell anemia mutations
Dialogue: 0,0:10:20.01,0:10:21.38,Default,,0000,0000,0000,,are good.
Dialogue: 0,0:10:21.87,0:10:23.43,Default,,0000,0000,0000,,Taken to their extremes, though,
Dialogue: 0,0:10:23.46,0:10:25.76,Default,,0000,0000,0000,,they cause significant problems.
Dialogue: 0,0:10:26.34,0:10:29.46,Default,,0000,0000,0000,,This delicate balance\Nhighlights the constraints
Dialogue: 0,0:10:29.48,0:10:31.46,Default,,0000,0000,0000,,inherent in the human body,
Dialogue: 0,0:10:31.48,0:10:34.17,Default,,0000,0000,0000,,and the fact that the evolutionary process
Dialogue: 0,0:10:34.19,0:10:36.93,Default,,0000,0000,0000,,must work with the materials\Nalready available.
Dialogue: 0,0:10:37.30,0:10:38.58,Default,,0000,0000,0000,,In many instances,
Dialogue: 0,0:10:38.61,0:10:40.91,Default,,0000,0000,0000,,a change that improves\Nsurvival or reproduction
Dialogue: 0,0:10:40.93,0:10:42.10,Default,,0000,0000,0000,,in one sense
Dialogue: 0,0:10:42.12,0:10:45.45,Default,,0000,0000,0000,,may have cascading effects\Nthat carry their own risk.
Dialogue: 0,0:10:45.99,0:10:49.29,Default,,0000,0000,0000,,Evolution isn't an engineer\Nthat starts from scratch
Dialogue: 0,0:10:49.31,0:10:52.59,Default,,0000,0000,0000,,to create optimal solutions\Nto individual problems.
Dialogue: 0,0:10:53.08,0:10:55.78,Default,,0000,0000,0000,,Evolution is all about compromise.
Dialogue: 0,0:10:57.19,0:10:58.74,Default,,0000,0000,0000,,It's also important to remember,
Dialogue: 0,0:10:58.76,0:11:01.07,Default,,0000,0000,0000,,when considering\Nour bodies' vulnerabilities,
Dialogue: 0,0:11:01.09,0:11:03.28,Default,,0000,0000,0000,,that from an evolutionary perspective,
Dialogue: 0,0:11:03.30,0:11:05.84,Default,,0000,0000,0000,,health isn't the most important currency.
Dialogue: 0,0:11:05.86,0:11:07.57,Default,,0000,0000,0000,,Reproduction is.
Dialogue: 0,0:11:07.59,0:11:11.73,Default,,0000,0000,0000,,Success is measured\Nnot by how healthy an individual is,
Dialogue: 0,0:11:11.75,0:11:13.60,Default,,0000,0000,0000,,or by how long she lives,
Dialogue: 0,0:11:13.62,0:11:17.57,Default,,0000,0000,0000,,but by how many copies of her genes\Nshe passes to the next generation.
Dialogue: 0,0:11:18.33,0:11:19.83,Default,,0000,0000,0000,,This explains why a mutation
Dialogue: 0,0:11:19.86,0:11:22.39,Default,,0000,0000,0000,,like the one that causes\NHuntington's disease,
Dialogue: 0,0:11:22.41,0:11:25.08,Default,,0000,0000,0000,,another degenerative\Nneurological disorder,
Dialogue: 0,0:11:25.11,0:11:28.34,Default,,0000,0000,0000,,hasn't been eliminated\Nby natural selection.
Dialogue: 0,0:11:28.36,0:11:30.12,Default,,0000,0000,0000,,The mutation's detrimental effects
Dialogue: 0,0:11:30.15,0:11:34.56,Default,,0000,0000,0000,,usually don't appear until after\Nthe typical age of reproduction,
Dialogue: 0,0:11:34.58,0:11:38.10,Default,,0000,0000,0000,,when affected individuals\Nhave already passed on their genes.
Dialogue: 0,0:11:38.86,0:11:40.03,Default,,0000,0000,0000,,As a whole,
Dialogue: 0,0:11:40.05,0:11:43.74,Default,,0000,0000,0000,,the biomedical community\Nfocuses on proximate explanations
Dialogue: 0,0:11:43.77,0:11:46.53,Default,,0000,0000,0000,,and uses them to shape\Ntreatment approaches.
Dialogue: 0,0:11:46.94,0:11:49.59,Default,,0000,0000,0000,,Proximate explanations\Nfor health conditions
Dialogue: 0,0:11:49.61,0:11:51.75,Default,,0000,0000,0000,,consider the immediate factors:
Dialogue: 0,0:11:51.78,0:11:54.70,Default,,0000,0000,0000,,What's going on inside\Nsomeone's body right now
Dialogue: 0,0:11:54.73,0:11:56.86,Default,,0000,0000,0000,,that caused a particular problem.
Dialogue: 0,0:11:57.20,0:11:58.93,Default,,0000,0000,0000,,Nearsightedness, for example,
Dialogue: 0,0:11:58.96,0:12:02.27,Default,,0000,0000,0000,,is usually the result of changes\Nto the shape of the eye
Dialogue: 0,0:12:02.29,0:12:05.02,Default,,0000,0000,0000,,and can be easily corrected with glasses.
Dialogue: 0,0:12:06.06,0:12:09.19,Default,,0000,0000,0000,,But as with the genetic\Nconditions I've discussed,
Dialogue: 0,0:12:09.21,0:12:13.27,Default,,0000,0000,0000,,a proximate explanation\Nonly provides part of the bigger picture.
Dialogue: 0,0:12:13.78,0:12:16.32,Default,,0000,0000,0000,,Adopting an evolutionary perspective
Dialogue: 0,0:12:16.35,0:12:20.61,Default,,0000,0000,0000,,to consider the broader question\Nof why do we have this problem
Dialogue: 0,0:12:20.63,0:12:22.21,Default,,0000,0000,0000,,to begin with --
Dialogue: 0,0:12:22.24,0:12:26.34,Default,,0000,0000,0000,,what evolutionary medicine calls\Nthe ultimate perspective --
Dialogue: 0,0:12:26.36,0:12:29.28,Default,,0000,0000,0000,,can give us insight\Ninto nonimmediate factors
Dialogue: 0,0:12:29.30,0:12:30.84,Default,,0000,0000,0000,,that affect our health.
Dialogue: 0,0:12:31.16,0:12:32.31,Default,,0000,0000,0000,,This is crucial,
Dialogue: 0,0:12:32.33,0:12:36.40,Default,,0000,0000,0000,,because it can suggest ways\Nby which you can mitigate your own risk
Dialogue: 0,0:12:36.42,0:12:38.26,Default,,0000,0000,0000,,or that of friends and family.
Dialogue: 0,0:12:39.57,0:12:41.27,Default,,0000,0000,0000,,In the case of nearsightedness,
Dialogue: 0,0:12:41.29,0:12:43.04,Default,,0000,0000,0000,,some research suggests
Dialogue: 0,0:12:43.06,0:12:46.36,Default,,0000,0000,0000,,that one reason it's becoming\Nmore common in some populations
Dialogue: 0,0:12:46.38,0:12:48.28,Default,,0000,0000,0000,,is that many people today,
Dialogue: 0,0:12:48.31,0:12:50.53,Default,,0000,0000,0000,,including most of us in this room,
Dialogue: 0,0:12:50.55,0:12:53.97,Default,,0000,0000,0000,,spend far more time reading, writing
Dialogue: 0,0:12:53.99,0:12:56.51,Default,,0000,0000,0000,,and engaging with various types of screen
Dialogue: 0,0:12:56.54,0:13:00.58,Default,,0000,0000,0000,,than we do outside, interacting\Nwith the world on a bigger scale.
Dialogue: 0,0:13:01.33,0:13:04.66,Default,,0000,0000,0000,,In evolutionary terms,\Nthis is a recent change.
Dialogue: 0,0:13:05.06,0:13:07.47,Default,,0000,0000,0000,,For most of human evolutionary history,
Dialogue: 0,0:13:07.49,0:13:10.82,Default,,0000,0000,0000,,people used their vision\Nacross a broader landscape,
Dialogue: 0,0:13:10.84,0:13:14.26,Default,,0000,0000,0000,,spending more time in activities\Nlike hunting and gathering.
Dialogue: 0,0:13:14.84,0:13:19.42,Default,,0000,0000,0000,,The increase in recent years\Nin what's termed "near work,"
Dialogue: 0,0:13:19.44,0:13:22.44,Default,,0000,0000,0000,,focusing intensely on objects\Ndirectly in front of us
Dialogue: 0,0:13:22.47,0:13:24.32,Default,,0000,0000,0000,,for long periods of time,
Dialogue: 0,0:13:24.34,0:13:26.38,Default,,0000,0000,0000,,strains our eyes differently
Dialogue: 0,0:13:26.40,0:13:28.93,Default,,0000,0000,0000,,and affects the physical shape of the eye.
Dialogue: 0,0:13:29.74,0:13:32.08,Default,,0000,0000,0000,,When we put all these pieces together,
Dialogue: 0,0:13:32.10,0:13:35.40,Default,,0000,0000,0000,,this ultimate explanation\Nfor nearsightedness --
Dialogue: 0,0:13:35.43,0:13:40.46,Default,,0000,0000,0000,,that environmental and behavioral change\Nimpact the way we use our eyes --
Dialogue: 0,0:13:40.48,0:13:43.43,Default,,0000,0000,0000,,helps us better understand\Nthe proximate cause.
Dialogue: 0,0:13:43.74,0:13:46.47,Default,,0000,0000,0000,,And an inescapable conclusion emerges --
Dialogue: 0,0:13:47.03,0:13:48.36,Default,,0000,0000,0000,,my mother was right,
Dialogue: 0,0:13:48.39,0:13:52.24,Default,,0000,0000,0000,,I probably should have spent\Na little less time with my nose in a book.
Dialogue: 0,0:13:53.16,0:13:55.70,Default,,0000,0000,0000,,This is just one\Nof many possible examples.
Dialogue: 0,0:13:56.05,0:14:00.19,Default,,0000,0000,0000,,So the next time you or a loved one\Nare faced with a health challenge,
Dialogue: 0,0:14:00.21,0:14:02.32,Default,,0000,0000,0000,,whether it's obesity or diabetes,
Dialogue: 0,0:14:02.34,0:14:04.02,Default,,0000,0000,0000,,an autoimmune disorder,
Dialogue: 0,0:14:04.05,0:14:05.89,Default,,0000,0000,0000,,or a knee or back injury,
Dialogue: 0,0:14:05.91,0:14:07.16,Default,,0000,0000,0000,,I encourage you to think
Dialogue: 0,0:14:07.18,0:14:09.97,Default,,0000,0000,0000,,about what an ultimate\Nperspective can contribute.
Dialogue: 0,0:14:10.55,0:14:12.85,Default,,0000,0000,0000,,Understanding that your health
Dialogue: 0,0:14:12.87,0:14:16.92,Default,,0000,0000,0000,,is affected not just by what's going on\Nin your body right now,
Dialogue: 0,0:14:16.94,0:14:21.24,Default,,0000,0000,0000,,but also by your genetic inheritance,\Nculture and history,
Dialogue: 0,0:14:21.26,0:14:23.90,Default,,0000,0000,0000,,can help you make more informed decisions
Dialogue: 0,0:14:23.92,0:14:27.26,Default,,0000,0000,0000,,about predispositions,\Nrisks and treatments.
Dialogue: 0,0:14:28.49,0:14:29.66,Default,,0000,0000,0000,,As for me,
Dialogue: 0,0:14:29.69,0:14:32.32,Default,,0000,0000,0000,,I won't claim that an evolutionary\Nmedicine perspective
Dialogue: 0,0:14:32.35,0:14:35.12,Default,,0000,0000,0000,,has always directly\Ninfluenced my decisions,
Dialogue: 0,0:14:35.14,0:14:37.01,Default,,0000,0000,0000,,such as my choice of spouse.
Dialogue: 0,0:14:37.40,0:14:39.10,Default,,0000,0000,0000,,It turned out, though,
Dialogue: 0,0:14:39.12,0:14:41.54,Default,,0000,0000,0000,,that not following\Nthe traditional practice
Dialogue: 0,0:14:41.57,0:14:43.96,Default,,0000,0000,0000,,of marrying within the Jewish community
Dialogue: 0,0:14:43.98,0:14:46.57,Default,,0000,0000,0000,,ultimately worked in my favor genetically,
Dialogue: 0,0:14:46.60,0:14:49.99,Default,,0000,0000,0000,,reducing the odds of me\Nhaving a baby with Tay-Sachs.
Dialogue: 0,0:14:50.47,0:14:54.20,Default,,0000,0000,0000,,It's a great example of why\Nnot every set of Ashkenazi parents
Dialogue: 0,0:14:54.22,0:14:57.36,Default,,0000,0000,0000,,should hope that their daughter\Nmarries "a nice Jewish boy."
Dialogue: 0,0:14:57.39,0:14:58.39,Default,,0000,0000,0000,,(Laughter)
Dialogue: 0,0:14:58.41,0:14:59.56,Default,,0000,0000,0000,,(Audience) Woo-hoo!
Dialogue: 0,0:14:59.59,0:15:01.34,Default,,0000,0000,0000,,More importantly, though,
Dialogue: 0,0:15:01.36,0:15:04.30,Default,,0000,0000,0000,,the experience of learning\Nabout my own genes
Dialogue: 0,0:15:04.32,0:15:07.92,Default,,0000,0000,0000,,taught me to think differently\Nabout health in the long run,
Dialogue: 0,0:15:07.94,0:15:11.82,Default,,0000,0000,0000,,and I hope sharing my story\Ninspires you to do the same.
Dialogue: 0,0:15:11.85,0:15:13.00,Default,,0000,0000,0000,,Thank you.
Dialogue: 0,0:15:13.02,0:15:14.50,Default,,0000,0000,0000,,(Applause)