[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:21.30,0:00:24.18,Default,,0000,0000,0000,,Behavior is written in the genes.
Dialogue: 0,0:00:24.18,0:00:26.03,Default,,0000,0000,0000,,All of us have innate behaviors;
Dialogue: 0,0:00:26.03,0:00:28.82,Default,,0000,0000,0000,,all animals are born with behaviors.
Dialogue: 0,0:00:28.82,0:00:33.73,Default,,0000,0000,0000,,Behaviors which through evolution \Nhave become more complex.
Dialogue: 0,0:00:33.76,0:00:35.01,Default,,0000,0000,0000,,In many aspects,
Dialogue: 0,0:00:35.01,0:00:38.59,Default,,0000,0000,0000,,behavior in males and females\Nof the same species is different.
Dialogue: 0,0:00:38.61,0:00:40.49,Default,,0000,0000,0000,,These differences in behavior
Dialogue: 0,0:00:40.52,0:00:43.71,Default,,0000,0000,0000,,are due to differences in the wiring\Nof the nervous system.
Dialogue: 0,0:00:43.73,0:00:48.31,Default,,0000,0000,0000,,At the same time, these differences\Nin wiring are established genetically.
Dialogue: 0,0:00:48.33,0:00:52.16,Default,,0000,0000,0000,,Aggression is a behavior\Nthat in general is specific to males.
Dialogue: 0,0:00:52.18,0:00:54.45,Default,,0000,0000,0000,,We see it in species\Nthat are very different,
Dialogue: 0,0:00:54.45,0:00:56.87,Default,,0000,0000,0000,,evolutionarily apart from each other.
Dialogue: 0,0:00:56.87,0:00:59.51,Default,,0000,0000,0000,,The way each one\Nof these species fights is different
Dialogue: 0,0:00:59.54,0:01:01.06,Default,,0000,0000,0000,,but the mechanisms are similar
Dialogue: 0,0:01:01.06,0:01:03.14,Default,,0000,0000,0000,,and the reasons are almost\Nalways the same.
Dialogue: 0,0:01:03.14,0:01:06.45,Default,,0000,0000,0000,,Males fight for females,\Nfor food, or for territory.
Dialogue: 0,0:01:08.40,0:01:10.49,Default,,0000,0000,0000,,I study aggression in flies.
Dialogue: 0,0:01:12.78,0:01:15.08,Default,,0000,0000,0000,,You are about to see an attack.
Dialogue: 0,0:01:17.52,0:01:19.27,Default,,0000,0000,0000,,One animal is going to stand up
Dialogue: 0,0:01:19.30,0:01:23.05,Default,,0000,0000,0000,,and is going to hurl its body-weight\Nat his opponent.
Dialogue: 0,0:01:25.65,0:01:28.33,Default,,0000,0000,0000,,The other one, meanwhile,\Nis going to try to escape.
Dialogue: 0,0:01:28.65,0:01:30.67,Default,,0000,0000,0000,,Why do I study aggression in flies?
Dialogue: 0,0:01:30.70,0:01:33.51,Default,,0000,0000,0000,,Because the behavior,\Nthat I'm interested in understanding,
Dialogue: 0,0:01:33.54,0:01:35.77,Default,,0000,0000,0000,,is the same, and the system\Nis much simpler.
Dialogue: 0,0:01:35.80,0:01:38.12,Default,,0000,0000,0000,,It's like studying a model.
Dialogue: 0,0:01:38.83,0:01:41.19,Default,,0000,0000,0000,,Sometimes it happens\Nthat the other animal,
Dialogue: 0,0:01:41.21,0:01:45.37,Default,,0000,0000,0000,,instead of escaping,\Nstays and starts to fight,
Dialogue: 0,0:01:46.86,0:01:49.40,Default,,0000,0000,0000,,and then something\Nwe call "boxing" occurs.
Dialogue: 0,0:01:57.08,0:02:01.03,Default,,0000,0000,0000,,Something crucial about attacking\Nis that only the males do it.
Dialogue: 0,0:02:01.05,0:02:04.11,Default,,0000,0000,0000,,The one who attacks first\Nis much more likely to win.
Dialogue: 0,0:02:04.14,0:02:06.35,Default,,0000,0000,0000,,And males only attack other males.
Dialogue: 0,0:02:06.38,0:02:08.22,Default,,0000,0000,0000,,Females never attack.
Dialogue: 0,0:02:11.76,0:02:14.61,Default,,0000,0000,0000,,So, why study behavior in flies?
Dialogue: 0,0:02:14.61,0:02:16.74,Default,,0000,0000,0000,,Because their behaviors\Nare the same as ours:
Dialogue: 0,0:02:16.74,0:02:21.81,Default,,0000,0000,0000,,Flies sleep, eat, court, fight,\Nlearn, and remember.
Dialogue: 0,0:02:22.28,0:02:24.42,Default,,0000,0000,0000,,The nervous system is much simpler;
Dialogue: 0,0:02:24.44,0:02:28.20,Default,,0000,0000,0000,,and the genes that play a role\Nin this behavior are very similar.
Dialogue: 0,0:02:28.20,0:02:32.35,Default,,0000,0000,0000,,So, studying aggression in flies\Nallows us to understand
Dialogue: 0,0:02:32.35,0:02:35.63,Default,,0000,0000,0000,,how this behavior develops\Nin other species.
Dialogue: 0,0:02:36.32,0:02:41.64,Default,,0000,0000,0000,,A key element when deciding\Nwhether to court or attack
Dialogue: 0,0:02:41.69,0:02:44.91,Default,,0000,0000,0000,,is determining the sex\Nof the other animal.
Dialogue: 0,0:02:45.49,0:02:49.24,Default,,0000,0000,0000,,All males are programmed to decide\Nbetween courtship or aggression,
Dialogue: 0,0:02:49.24,0:02:51.45,Default,,0000,0000,0000,,but the sensory signals they use
Dialogue: 0,0:02:51.47,0:02:54.84,Default,,0000,0000,0000,,to see if what is in front of them\Nis a male or a female are different;
Dialogue: 0,0:02:54.87,0:02:58.19,Default,,0000,0000,0000,,for example, in our species\Nvisual signals are very important.
Dialogue: 0,0:02:59.93,0:03:02.17,Default,,0000,0000,0000,,This is what a fly has in front of itself.
Dialogue: 0,0:03:05.00,0:03:07.03,Default,,0000,0000,0000,,So, how does it decide?
Dialogue: 0,0:03:07.53,0:03:09.86,Default,,0000,0000,0000,,Evidently, it somehow makes a decision
Dialogue: 0,0:03:09.86,0:03:13.11,Default,,0000,0000,0000,,because what it is going to do\Nis very different in each case.
Dialogue: 0,0:03:13.11,0:03:15.82,Default,,0000,0000,0000,,When there is a male\Nentering its territory,
Dialogue: 0,0:03:15.82,0:03:17.89,Default,,0000,0000,0000,,it is going to start attacking
Dialogue: 0,0:03:18.50,0:03:22.29,Default,,0000,0000,0000,,and to chase him everywhere\Nuntil the other one decides to escape.
Dialogue: 0,0:03:23.16,0:03:26.06,Default,,0000,0000,0000,,When there is a female,\Nhe extends his wing for her.
Dialogue: 0,0:03:26.08,0:03:28.39,Default,,0000,0000,0000,,As you can see, he literally courts her.
Dialogue: 0,0:03:30.78,0:03:32.25,Default,,0000,0000,0000,,He chases her everywhere,
Dialogue: 0,0:03:32.25,0:03:35.05,Default,,0000,0000,0000,,he sings to her until\Nhe has finally won her over.
Dialogue: 0,0:03:36.74,0:03:39.61,Default,,0000,0000,0000,,So the question is, how does it know?
Dialogue: 0,0:03:39.61,0:03:41.10,Default,,0000,0000,0000,,How does it decide?
Dialogue: 0,0:03:41.10,0:03:46.41,Default,,0000,0000,0000,,What are the key signals that it uses\Nto decide if it has to court or attack?
Dialogue: 0,0:03:46.69,0:03:50.68,Default,,0000,0000,0000,,If we can identify these signals,\Ncan we change them?
Dialogue: 0,0:03:50.71,0:03:53.02,Default,,0000,0000,0000,,Can we invert this decision?
Dialogue: 0,0:03:53.02,0:03:55.03,Default,,0000,0000,0000,,In insects, like in many species,
Dialogue: 0,0:03:55.03,0:03:58.64,Default,,0000,0000,0000,,chemical signals called pheromones\Nare very important.
Dialogue: 0,0:03:58.66,0:04:03.22,Default,,0000,0000,0000,,These signals are produced\Nby one animal and detected by another.
Dialogue: 0,0:04:03.22,0:04:04.93,Default,,0000,0000,0000,,So, then something we decided to do
Dialogue: 0,0:04:04.93,0:04:07.79,Default,,0000,0000,0000,,was to switch the pheromones,\Nchange the scent.
Dialogue: 0,0:04:08.16,0:04:09.66,Default,,0000,0000,0000,,To make it happen,
Dialogue: 0,0:04:09.66,0:04:13.82,Default,,0000,0000,0000,,we manipulated the expression\Nof one gene, called "transformer".
Dialogue: 0,0:04:13.85,0:04:17.55,Default,,0000,0000,0000,,"Transformer" is turned on in females\Nand turned off in males.
Dialogue: 0,0:04:17.58,0:04:24.41,Default,,0000,0000,0000,,So, something that we can do\Nis to mute the "transformer" in females
Dialogue: 0,0:04:24.41,0:04:26.74,Default,,0000,0000,0000,,and force its acquisition in males.
Dialogue: 0,0:04:26.74,0:04:30.36,Default,,0000,0000,0000,,In doing so, we masculinize females\Nand feminize males.
Dialogue: 0,0:04:30.36,0:04:34.22,Default,,0000,0000,0000,,But not all over, we aren't going\Nto manipulate the entire animal.
Dialogue: 0,0:04:34.22,0:04:35.98,Default,,0000,0000,0000,,We are going to choose certain parts,
Dialogue: 0,0:04:36.00,0:04:39.21,Default,,0000,0000,0000,,in particular the cells\Nwhich produce pheromones.
Dialogue: 0,0:04:39.21,0:04:44.28,Default,,0000,0000,0000,,What we can achieve are females\Nthat have masculine pheromones
Dialogue: 0,0:04:44.28,0:04:47.16,Default,,0000,0000,0000,,or males that have feminine pheromones;
Dialogue: 0,0:04:47.19,0:04:49.89,Default,,0000,0000,0000,,then we are going to see\Nwhat is going to happen
Dialogue: 0,0:04:49.92,0:04:51.91,Default,,0000,0000,0000,,when a normal male, unmanipulated,
Dialogue: 0,0:04:51.94,0:04:55.22,Default,,0000,0000,0000,,meets a female\Nthat has masculine pheromones.
Dialogue: 0,0:04:56.64,0:04:58.71,Default,,0000,0000,0000,,This is what happens, it attacks her.
Dialogue: 0,0:04:58.74,0:05:01.22,Default,,0000,0000,0000,,When she enters his territory,\Nhe does something
Dialogue: 0,0:05:01.25,0:05:03.84,Default,,0000,0000,0000,,that he would never do\Nin front of a normal female,
Dialogue: 0,0:05:03.86,0:05:05.74,Default,,0000,0000,0000,,which is start attacking her.
Dialogue: 0,0:05:06.57,0:05:08.89,Default,,0000,0000,0000,,When we carried out\Nthe reciprocal experiment,
Dialogue: 0,0:05:08.89,0:05:13.67,Default,,0000,0000,0000,,what we found was that males\Nwith feminine pheromones were courted.
Dialogue: 0,0:05:15.76,0:05:17.18,Default,,0000,0000,0000,,What does this mean?
Dialogue: 0,0:05:17.66,0:05:21.54,Default,,0000,0000,0000,,That males are\Ngenetically programmed to court
Dialogue: 0,0:05:21.54,0:05:23.80,Default,,0000,0000,0000,,when they find feminine pheromones
Dialogue: 0,0:05:23.80,0:05:27.75,Default,,0000,0000,0000,,and to attack when they find\Nmasculine pheromones.
Dialogue: 0,0:05:28.55,0:05:30.48,Default,,0000,0000,0000,,But, this behavior,
Dialogue: 0,0:05:31.44,0:05:35.13,Default,,0000,0000,0000,,this innate behavior\Nthat is wired in the brain --
Dialogue: 0,0:05:35.13,0:05:40.59,Default,,0000,0000,0000,,court if there are feminine pheromones,\Nattack if there are masculine pheromones --
Dialogue: 0,0:05:40.59,0:05:42.43,Default,,0000,0000,0000,,can it be changed?
Dialogue: 0,0:05:42.47,0:05:45.44,Default,,0000,0000,0000,,Could it be that an animal\Nas simple as a fly
Dialogue: 0,0:05:45.44,0:05:50.06,Default,,0000,0000,0000,,could learn from its experience\Nand modify a behavior which is innate,
Dialogue: 0,0:05:50.06,0:05:53.01,Default,,0000,0000,0000,,something which is wired\Nin its nervous system?
Dialogue: 0,0:05:54.16,0:05:58.11,Default,,0000,0000,0000,,To respond to this question,\Nwe did a similar experiment.
Dialogue: 0,0:05:58.11,0:06:00.29,Default,,0000,0000,0000,,Again, we manipulated the "transformer",
Dialogue: 0,0:06:00.29,0:06:02.53,Default,,0000,0000,0000,,but this time, in the females' brains.
Dialogue: 0,0:06:03.22,0:06:06.72,Default,,0000,0000,0000,,These females still have\Nfeminine pheromones
Dialogue: 0,0:06:06.74,0:06:09.16,Default,,0000,0000,0000,,but they act like males.
Dialogue: 0,0:06:09.19,0:06:13.13,Default,,0000,0000,0000,,We muted their "transformer" in the brain\Nto turn them into aggressive females.
Dialogue: 0,0:06:13.15,0:06:17.04,Default,,0000,0000,0000,,They not only dislike courtship completely\Nbut they also attack.
Dialogue: 0,0:06:18.51,0:06:19.73,Default,,0000,0000,0000,,We then asked ourselves,
Dialogue: 0,0:06:19.73,0:06:23.25,Default,,0000,0000,0000,,what is a male going to do\Nwhen it meets a female
Dialogue: 0,0:06:23.27,0:06:26.36,Default,,0000,0000,0000,,that has female pheromones\Nbut is aggressive?
Dialogue: 0,0:06:26.36,0:06:29.46,Default,,0000,0000,0000,,The first thing it's going to do\Nis court her as much as possible.
Dialogue: 0,0:06:29.48,0:06:32.86,Default,,0000,0000,0000,,It chases and chases her,\Nextends its wing, sings to her,
Dialogue: 0,0:06:32.86,0:06:36.31,Default,,0000,0000,0000,,but the moment comes\Nwhen he decides to change his behavior.
Dialogue: 0,0:06:36.90,0:06:40.13,Default,,0000,0000,0000,,The moment comes\Nafter so much ineffective courting
Dialogue: 0,0:06:40.16,0:06:42.50,Default,,0000,0000,0000,,and in addition to being attacked by her;
Dialogue: 0,0:06:42.51,0:06:45.12,Default,,0000,0000,0000,,he says, "enough is enough"\Nand ends up attacking her.
Dialogue: 0,0:06:45.12,0:06:49.32,Default,,0000,0000,0000,,This means that even an animal\Nas simple as a fly
Dialogue: 0,0:06:49.32,0:06:53.70,Default,,0000,0000,0000,,can learn from its experience\Nand modify its behavior.
Dialogue: 0,0:06:53.73,0:06:55.11,Default,,0000,0000,0000,,And not only that.
Dialogue: 0,0:06:55.11,0:07:00.05,Default,,0000,0000,0000,,When there are fights between two males,\Nthere is always a winner and a loser.
Dialogue: 0,0:07:00.08,0:07:02.50,Default,,0000,0000,0000,,After a male loses many times
Dialogue: 0,0:07:02.50,0:07:05.11,Default,,0000,0000,0000,,what happens is that\Nhe suppresses this behavior.
Dialogue: 0,0:07:05.11,0:07:06.73,Default,,0000,0000,0000,,He stops fighting.
Dialogue: 0,0:07:07.72,0:07:11.68,Default,,0000,0000,0000,,This means that even in an animal\Nas simple as a fly
Dialogue: 0,0:07:11.72,0:07:14.20,Default,,0000,0000,0000,,not only behavior is in the genes,
Dialogue: 0,0:07:14.22,0:07:18.17,Default,,0000,0000,0000,,but the ability to learn from experience\Nand modify it is there, too.
Dialogue: 0,0:07:18.20,0:07:19.70,Default,,0000,0000,0000,,Thank you very much.
Dialogue: 0,0:07:19.70,0:07:22.69,Default,,0000,0000,0000,,(Applause)