the next couple of programs that we're having here is wednesday november fifth the graveyard girls will be here to tell us all about arlington cemetery and on thursday december eighteenth we're having silent big business with laurel and hardy and sherlock jr with buster keaton so without further ado i will hand you over to you don stop from science for the public good evening and thank professor and chair of the department of physics at brandeis university and i believe still co director of the brandeis program in quantitative biology he's here to explain a vitally important biological process how the d n a molecule is folded folded in the cell and why it's so important in medical and biological research dr khan to have received his ph d in theoretical physics from cornell university in one thousand nine hundred five he then became post doctoral fellow in physics at brown university and then a member of the school of mathematics at princeton university institute for advanced study and was a lecturer in physics at princeton before joining the physics department at brandeis in two thousand dr condit has received numerous awards for both his research and his teaching including the national science foundation  career and that's the acronym and the trial scholar award this year he was named one of fifteen howard hughes medical institute select professors in the nation he was also is also co author of a major textbook in bio physics the physical bio of the cell is co author we appreciate dr khan dev's willingness to expect him to explain this very significant work to the general public tonight and it is a great honor to wel him thanks yvonne and thanks to the library for inviting me and thank you all for coming out to to hopefully be attained by a little bit of science that i personally find very exciting and hopefully i will be able to convey some of that excitement to you tonight so let's see so everyone's familiar with d n a and genes i mean everyone's heard the concept of the genetic genome in the genetic code is that correct biological questions and it's a very sort of exciting time in science where there's a lot of crosstalk between physics biology chemistry computer science and hopefully you'll see some of that during today's presentation as well so so i think with you're familiar with the idea of genome and the d n a is being sort of a series of these letters and somehow these letters encode information that the cell needs in order to do its thing but on the other hand d n a is also a molecule meaning it has sort of physical properties like its with which is about two nanometers and it can be very very long in fact if you were to take all the d n a that's in every one of our cells and stretch it out and put it put all the sort of smaller so in other words the d n a has to be folded up about a million times over so that it can be can fit inside the cell and what scientists have been very interested in for the past few decades is  what is the folded nature what is the nature of this folded state and i'll explain what i mean by that and are there any rules to this folding because one thing you could imagine is that the folded state of the d n a inside the cell could just be completely random which is what you would get if you took this string and just sort of randomly sort of crunched it up and that it fits inside my hand right and what we'll see one of the sort of surprises that has come about over the last few decades is that actually this folded state is not random that there's patterns to it there's regularities to it and these regularities are turning out to be important for the function of d n a ok so that's a bit of an overview of what i'm going to talk about tonight but in order to get us there i thought it would be good if i gave you a little bit a sort of very short introduction to the history of genomes and this idea that there's this long string the molecule in our cells that contains the the the modern version of the modern sort of state inflicting certain genes because they bestow certain useful quantities to the organisms that you know that that idea goes back when humans first started sort of cultivating plants  and and cross breeding animals of course people didn't know what you know didn't know what the sort of molecular basis obviously of that was but they but there was certainly they that sort of discovered the idea that if they kept plants with useful traits then in the next generation those traits would be present and they could sort of slowly develop sort of species that or they could develop sort of plants that were useful in the sense that they produced useful results for forth human sort of  needs the first time people i mean so presumably people way back you know a few a few thousand years ago had been thinking about sort of of these problems but the first time it appears sort of in any kind of written for is not surprisingly in the time of the greeks and and sort of the it was hypocrisy who who thought about sort of the problem of heredity and and he had this kind of proposal that the there are these tiny similar idea and all the ideas leading up to mendel had sort of one basic component to them and that was the idea that that that sort of these traits that are inherited and you know what people noticed is that offspring were often similar to parents and the idea was that somehow that the parents contain some kind of a substance like a you can think of it as a fluid and then when you have the offspring you get kind of mixing of these fluid so there's this idea of mixing of traits and so that this offspring come up come up sort of as mixed versions of parents and this these ideas been really go go very far and it was really sort of in the mid eighteenth hundreds  with the work of gregor mendel that really sort of modern understanding of genes and genetics comes comes comes to light and of so you know if you kind of some of the younger members of the audience probably sort of seen this very recently some of you might have seen this many many years ago but mendel was sort of looking at p s he was growing peas in the p garden and then he was looking at sort of statistical properties or he was measuring how likely it was that that in the next generation as he was growing peas in the next generation that the plants had certain properties that the parent plants had and by sort of  analyzing these p d you know that the pieces as they were going from one generation to the other he came up with this key idea and the key idea was that there were some kind of you can think of is like atoms they're called genes today that there were some  basic factors that could not be divided that were sort of indivisible and that these factors contained that they carry traits and that these factors then that the parent parents carried these factors and it was these factors that were of bestowed upon the the offspring and that that sort of the idea of heredity so this was kind of mental ski insight that there was in today's language that there was a gene in some sense that made pods of the of the beans green versus yellow and then they were there was a gene or this little entity which he didn't know what it was that made that made the seeds either round or wrinkled or yellow or green or made the flowers purple or white so this was this is kind of the basic insight of mendel and then after mendel's discoveries so the next fifty years or so what we have is a period in science where people who are interested in this problem of heredity and what they're focusing on is the physical nature of the gene so what is this particle what is this thing that makes peas have seeds that are yellow versus green and so so the the kind of the big breakthrough create came then at the turn of the century so only forty years about later where these two guys  sensually proposed the idea that these things that people were seeing in microscopes called chromosomes again they didn't quite know what these things work or they would string the objects the objects that did that you could see in that you can kind of color in the cells so that therefore the name chromosomes that the idea was that somehow these contain the genes that these contain these objects these little stringy objects contain these fundamental particles of heredity that mendel had discovered by studying peace so it was then a couple of years later in at columbia university in the lab of thomas hunt morgan where this sort of chromosome hypothesis or chromosome idea the idea that these that these entities in cells called chromosomes carry genes it was essentially finally sort of proven by looking at by looking at various fruit flies and mutants of fruit flies with certain properties again very similar to the way that mendel was looking at p t s and looking at different properties of peas what morgan was doing was looking at fruit flies and was breeding fruit flies and then he found fruit flies that  had for instance short antenna where most where in normal fruit flies you have long antenna and then he found fruit flies that had black bodies where normally you have gray bodies and so what he was discovering here was the fact that there were genes that controlled traits are determined by genes and he was able to show that these genes are created by chromosomes in the way he was able to show that was to show that certain traits go with flies being male or female and so the idea and he then what people had observed was that the chromosomes in males and females were different and you made this logical connection that genes must reside on these chromosomes because the chromosomes are somehow related to the soup whether the flies are male or female and the genes than which are because the working in morgan's lab pretty much blowing off all his school work and he had this kind of crazy idea at the time was to make a genetic map so he had this idea that genes were somehow ordered on chromosomes because you know these chromosomes were stringy structures so they were like under the microscope they look like strings so that naturally then it's a then the idea was well if these genes sit on chromosomes then you can ask if you have genes a b and c d which order they go in like if you start from one end is it a b c or is it c b a so there's this so if you're thinking about the chromosome as being a linear structure then there is a sense in which you have an ordering of the genus and so what sturtevant figured out was ordering of these of these genes that carry the different properties of the fruit fly so he was able to say which gene is close to which other genes and the way he did that was by looking at which of these  properties of the fruit flies which of these properties went together ok so he noticed that that fruit fly that had a bull for instance that had black body were occurring more often together with the trait that they had cinnabar eyes than a fruit fly that had a black body and brown eyes so that then from that he was able to infer that the gene for cinnabar eyes in the gene for blackness were closer together along the chromosome than the gene for the black body in the brown eyes and so he was able to make the first chromosome map in this way genetic map and the genetic map is the idea of saying where on the chromosome the different genes reside ok so he wasn't able to tell you exactly you know first of all this is in one nine hundred thirteen the idea that it's d n a that that really in coding the genes was not even formulated yet but he was able to say aha there's this chromosome and this gene is here the other this gene is close to closest to it the next gene is further away and so forth and that was the big big great breakthrough of sturtevant all right so now let's fast forward and what's really amazing about the history of biology in particular molecular biology is that things are happening really really really fast like compared to the field that i that i that i sort of grew up in which is physics where if you if i were doing the history of physics you know maybe a history of modern physics i would i would go would happen sort of talk about five hundred years ago and talk about and then talk about newton and talk about you know before you know talk before and you can talk about kepler but the histories kind of very drawn out until we can come to the modern era where we're sort of finally getting to the point where we have all the kind of fundamental laws of physics on there our belt just goes really really fast and for our story today a key event is one hundred fifty three when watson and crick figured out the structure of d n a before watson and crick others had done experiments that showed that d n a is the part of the hundred seventy seven the entire genome of a virus a sequence which means that for this for the for some virus the sequence of these letters and these letters corresponds to the basic elements of the d n a which will tell you about the whole sequence and is is known and then the same thing is accomplished by one thousand nine hundred six so and in a mere twenty years for a much more complicated organism like baker's yeast two years later we have a sequence of of a worm and only five years later the human genome project is completed by by government sponsored in a private organization it's announced in two thousand and three and since two thousand and three medicine and and and that's where we're at today those fundamental changes have not quite yet occurred and that's one of the things that i want to talk about is what are the what are the sort of what are the issues that we face in really harnessing the power that want to talk about today are maps ok and one way to think about science is to really think about maps mostly what science has done over the past few thousand years is make maps of we make maps of things that we can't see and that's really sort of one of the fundamentally amazing things about science like we've mapped out the world of atoms we can't see an atom we can't even see it an atom under a microscope by doing various kinds of experiments we figured out what's the basis of the periodic table of elements we've mapped out the universe we know how old the universe is we know a lot about how the universe was formed but we cannot with our senses perceive the universe other than looking up at the night sky and getting some sense of it's really big out there and what i'm talking about today is the mapping of the stuff that's in us ourselves and more particularly within ourselves the d n a that is the blueprint that it's the information that's needed in order to in order to construct life in order to make life possible and and so so so today i will talk a lot about math and here's a map of a part of the human genome in fact this is a map of chromosome fourteen where each of the so called new clay of tides and there's four of them a t g c is colored with a different color and  and you can find these kinds of maps online and and there's there it's fun because there are these sort of discussion forums where people kind of gaze at these things and try to see some patterns but leaving that aside this  how big is the human genome well you know here's here's a little sort of a little graphic of the d n a molecule and what these little lines are those are sensually these base pairs imagine that the distance was not that small but was more something that that's reasonable on human scale say a millimeter a millimeter is you know if you try to put your if you try to put two of your fingers together and make it so that they're just touching that's about a millimeter ok so if that were the distance between two so if that were the distance between two of the essential e dots here because each dot here is one of these one of these nucleotides if that were to distance between two dots and you were to stretch out this molecule of d n a it would cover about three thousand kilometers three thousand kilometers that's this red line here superimposed on the on the map of africa what's amusing is this red line is exactly roughly the area where first humans arose just for the fun of it so so in other words if the distance between two of these see in other words if the distance between two of these little dots is a millimeter the human genome is three billion base pairs so three billion times a millet one millimeter is three but so imagine so you have a compartment that's the size of me and in that compartment you're going to fit a molecule whose length is this part of africa that's that's the problem that we're talking about that's this folded one of the you know one interesting questions always in finance has been from the dawn of sciences you know what is the position of man in the universe right and and so you know we like to think of ourselves as very complicated things maybe we are by some measure but that so we're nothing special on this scale ok newts have more d n a we have about as much of d n a as frogs so and only a little less than fruit flies so so anyway so so certainly if we were if we certainly sort of the cool things that humans do is is not related to the size of our to the size of our genome this three billion base pairs so where does it reside what is encoded in the g and this is the key question so we can read the genome ok but the key question is if we if you if i gave you the genome if i gave you the sequence and there it is in color code  is the information in the genome that tells us about the parts that make us the parts being the molecules that were composed of and those in the most important molecules that were composed of our protein so with the only part of the g can read is the part that says what are the components of a human or any other living organism components in the in the in the sense of the melech in the molecular parts what we don't know how to read it's how those parts are put together that's the key message i want to get across so here's sort of a little more of an explanation of that concept so what i've been talking about is d n a and one way to think about d n a and proteins is in terms of languages so there's two languages of living things the language of d n a and a it stands for nucleic acids and proteins the alphabet of this language only has four letters ok there's only four molecules and these molecules they make these two they make these rungs they make hard to make this sort of double helix whole structure where you have these sort of ladders and the ladders are the pairs because the g molecule comes always paired with c a molecule comes paired with t the c molecule comes paired with g this is what sort of watson and before actually watson and crick shar graf figured out and so when we talk about information that's encoded in the d n a that information is expressed as a more molecules that are strung together like beads on a string that make up a protein these twenty molecules here are denoted by different colors and different letters and they're actually called amino acids and here is sort of their structures and and when you string these molecules together they make a long chain of these amino acids and these chains make proteins and proteins are the molecules in our cells to do kind of the busy work of the cell they're the key key molecules in the cell and and what was figured out in the in the sixty's and seventy's when people talk about the genetic code we figured out the code what's been figured out is the translation between the language of d n a and the language of proteins in other words how is each one of these amino acids included in the d n a and the trick is that three letters of the d n a alphabet correspond to one letter of the protein a that sort of depicted here so this little wheel here says if i take the letter you of the d n a alphabet and this letter c of the d n a alphabet and say the letter you i get staring which is one of the amino acids and if on the other hand if i have  i get this protein i mean us so when we talk about in coding a protein in the d n a what we're talking about is a string of these triplets of d n a letters they're in the cell that reads this and what it says g a c it incorporates a spartak acid into a chain that makes up a protein ok so now we're getting you know since this is how this whole thing works right so you got all these you got this sequence and then you know every three letters tells you what's the amino acid so this is some amino acid and this is some you know acid in this is some you know acid and then you connect these amino acids and you get a prote n all right here's the problem if we take the part of the genome that code for these amino acids actually that code for the proteins that's only one percent of these three billion base only one percent of these three billion base pairs that make up the human genome we know what the what it what that what what that piece what that part of the genome does we know that it's code for protein what we don't know is what the other ninety nine the d n a ok that we know what it does what it codes for it tells us what the ingredients are what i'm showing you here is a recipe of how to make these things here are the ingredients and here's the problem the other ninety nine percent of the d n a what it is it's the recipe but the recipe is in some weird language this is i can read this but i don't know if anyone else can hear the i'm using it someone can which means you're from this part of the world it's kind of listen real to russian but ok but if i  you this this looks like language right because you can see their words and you know there's things that are kind of highlighted this says how do you make them eat this is how you roll the meat and the you know there's there's also there's all sorts of punctuation here that sort of x tells you that this is a language and you know there's some ways to try to decipher this language you know if you know a couple of words and stuff like that but here's the problem we don't even know how this language of of the in the d n a is structured meaning it's the equivalent to the following problem someone gave you these ingredients and then gave you a recipe in a completely unknown language but then got rid of all the punctuation ok so now somewhere you know so now you've got no punctuation you don't know what the language is and somebody's trying to your sport you're supposed to figure out is how this all this stuff tells you tells you how to take these ingredients and make this ok so that's that's really the problem we have we have we have we have ingredients namely how do these proteins how do you connect them up how do you put them together to make a human that is equivalent to trying to figure out this this recipe ok so  this machine is engaged has to read the gene in other words when this machine is engaged so as to produce the components that you need for making the person or something else is controlled by all sorts of other parts of the d n a which have to be in contact with the machine and nurtured to be in contact the d n a has to be folded up and that's where the problem of folding comes in so so then let me then just spend a little bit of time telling you about what we've learned about folding and how we learn about folding so the way we learn about folding is there's two techniques and this is a technique that we've been using in my lab is by simply labeling the gene so what we do is by chemical  sort of trickery if you like we have we have a gene on the d n a and we make that gene glow a certain color so we can have a gene glow and blue gene glow in yellow gene blue and red so here's a gene that we've made yellow turn glow in yellow has a genome a glowing blue and here is a gene that we made blue and red and so what we can do now is we can by doing that we can investigate the position of the genes in the cell and here is the cell so the cell that shown here is our favorite sort of model cell cell it's a bacterial cell and the sort of thing we're doing here is we're simply using bacterial cells as a model system because we think they're you know we have this notion that there are some general rules of how this d n a sold it so maybe if we can understand those rules in an compartment the cell and here's an artist's rendition of what this packed state looks like the yellow stuff is the d n a so that gives you an impression of just this right if i were to fold up the d n a get something really messy and that's this yellow string here ok so the way we're trying to understand the folded state is we look at the position of the different of different genes and and i'm just going to tell you this little story and then i'll stop so we do experiments we look at the position of the genes and see one of the things about science is it's sort of useless to do experiments if unless you are in this you come to them with a certain prejudice so it's good you know people talk about science having needing to be objective that's completely true but whenever we do science and whenever we do experiments in science we always come to the experiments with a certain idea of what we think is going to happen ok and sometimes and most interesting things that happen in science is when the experiments reveal something that we did not expect and and  darwin i think said that very nicely in the letter to to henry fossett in eighty six eight hundred sixty one and said about thirty years ago there was much talk the geology geologist only ought only to observe and not theorize and i well remember someone saying that at this rate a man might as well go into a gravel pit and count the pebbles and describe the colors how odd it is that anyone should not see that all observation must be for or against some view if it is to be of any service  whenever we go into the lab we have a particular view and make observations so the idea was the following what we expected is that if i were to label a gene and now i fold up the d n a what i would expect is that gene should be pretty much anywhere at random inside the cell ok why because the length of the d n a is a thousand times bigger than the size of the cells have to fold it's a thousand times and by the end of the day when i've done these thousand foldings where location in other words if i label the gene blue then in every cell that gene is roughly the this blue gene is roughly for instance in the middle of the cell ok somehow the d n a is fold it exactly in exe in exactly the same way and this precision of the position of the gene within the cell is less than ten percent of the length of the cell so it's as though that every it's as though every single gene in any  little g p s device like it has a little i phone with a g p s and it tells it where to sit in the cell of course there's no g p s device in fact we don't know what this g p s device is but what we've discovered is that there's an order to this folding even though it would it sort of completely eluded us that there was a possibility to this happening because of the fact that the d n a so huge and it has to be compacted in such a small body and  and this led us to have sort of a model of this of the structure of this chromosome having to do with it being like a little rubber band sort of compacted rubber band that we think we can we now have an idea of how this of this how this organization comes about but it's not that important if there's another experiment i'm not going to bore you with which to which which produces the same result and so the basic result is that every gene in equal i sit at a specific place now what's really exciting is that the exact same thing is found or very similar thing as is found for human genes so again here's a here's chromosome fourteen and this chromosome has one hundred sixty one hundred six million base pairs there's about twelve hundred genes in there each gene you see you can see this each gene is about a thousand base pairs so only one hundred thousand bases is genes but there's a million total one hundred sorry hundred million so us a less than one percent of this thing is is is gene and and here's what experiments where each gene in the human in a human cell was colored just like i we colored individual genes here each chromosome my apology each chromosome was covered in a different color and what you find is that chromosomes occupy certain territory so here's i was showing a chromosome fourteen here's chromosome fourteen again the total amount of d n a here is meters three meters in a compartment that's a million times smaller you expect to see a jumbled mess something like this where there is no structure but w structure and what we now know is that that structure is functional meaning that if we disrupt the structure we get cells that don't behave properly and going back to the idea of what's the information encoded in the the question we're all start where type trying to tackle is where in the sequence of the d n a is the information about the structure encoded where does that information reside and we don't have an answer to that what we do know and this is some very sort of recent studies is that for instance and this is now becoming sort of quite a big area of research is that when we look at maps and without getting into details of what this particular map is but when we look at maps of this folded structure in info in cancer cells then we find that those maps correlate with certain genetic abnormalities in these cancer cells in other words the disruption of this of this of this folded state seems to correlate with with genetic variant variations that occur in cancer cells sort of an idea that by studying how the folded what the folded state of the genome is we can learn we leads among other things can't so so let me know and just summarize and i would be happy to get them in questions so what we're trying to do at this point and we only have a few  examples where we've done this and in when i say we i mean the community of scientists that scientists that i belong to is we're looking at these different organisms that the bacteria i talked about there's the bakers yeast that i mentioned that was one of the first organisms that we sequence here is human genomes and we're trying to understand this fold state because we believe that this folded state carries some important information about the recipe about what is it that makes it so that the components the proteins that make up a living things what is it that tells those components how to assemble in which order when so as to get something like a human being from the point of view of medicine the reason we want to understand this is because when that reading of the recipe fails is when we get does and just i think i'm going to stop here and this work is very serious interdisciplinary there's a number of students and other faculty involved that i work with julie theriault so good friend of mine she's a professor of cell biology at stanford and  well you could and it's not as bad as that because you could even though you can't read the recipe you could figure out that if the recipe gets messed up right here then piece that this machine gets deleted something that happens for instance in cancer you have deletions that get deleted then if i knew how to you know then i missed the information that i should be making that should be grinding them and i think that's not the grinding it's the mixing of the meat to be done with the mix or not by hand for summer so if i mean that this apparently won't come out right so so so you know so so even though i don't understand that this word means machine i can certainly do a study where i can say that if that word is missing something goes wrong the problem is then i think you know why we are trying to get past that model and try to read this is that make it that would allow passengers don't have their seat belts fastened so if you're doing this kind of analysis you would have to conclude that for the for the flight of an airplane it's critical that their seat belts on the plane but it isn't that just has to do with f a a regulations so one of the problems with doing these kinds of things we find these pieces of the d n a which are critical but we don't know if that it's just like the seatbelts we don't know if this is at all relevant for the basic process that that leads to disease and i think that's that's  making it harder for us to to really sort of treat and understand what the gentleman back there had a question so what what reads the recipe part part and what reads recipe part what reads it so you talked about the thing that transcribes the d n a into protein so the great question is so we know some parts ok so there are some parts that serve as landing sites for sort of proteins and the and that these these guys here and these proteins what they do is they by contacting the machine that makes that read the gene day turn that machine on project code project there's about thirty thirty to a hundred and thirty ish institutions involved and a few hundred scientists and and it's trying to understand all the different ways all the different sort of molech killer processes involved in reading the recipe i told you one and there's a few others that we know about and so so the code has to now we're at the in this stage of trying to kind of read the nineteenth there are the other ninety nine percent and so far as far as i remember it's only one percent of that that's been that's been kind of read out but slow going it's not as easy as just reading the d n a when i say reading it actually means we have no problem in actually getting that we haven't you got it so we have no problem in getting the been getting and getting that right it's now going in and saying a ha what this bit does is it binds this protein and by binding this protein it turns the genes something gene on or off and that's that's proving to be far more difficult than what we did in two thousand and three which is read the human  so so for instance and fruit flies their specific genes that that if you mess with and they altered their behavior and one that i'm familiar with is that the i forget it was the male or the female guessing ma twenty thousand there are twenty thousand other words there's twenty thousand were made out of twenty thousand different kinds of lego blocks ok so the one percent specifies twenty thousand different ingredients ok twenty thousand different which is only ten times as many as in a little simple bacterium called eco light so the complexity has to lie in the recipe in how these twenty thousand lego blocks are put together and for all of you who play with lego blocks you know even with a few different kinds of lego blocks can get very complicated  so that's the problem with things like identifying behavior is that it's usually there are some examples where you can find one gene but usually it's it's a collection of many genes acting  particular funny way where you can connect in this way as many as you know millions and billions of these units right so if you connect millions and billions of these units you'll get something like g eight c get something that that looks like that right then it can and then and then the code on is just three in a row now the reason you need three in a row is you have twenty proteins and so if you have if you have one you can't just specify one protein with one letter because you have only four possibilities here and there twenty i mean i think if you had two letters then the number of things you could specify sixteen because you have four possibilities for this and four of this so the total of sixteen that still not enough three get to sixty four and i have more than enough and so you actually so that means that three letter if you use three letters that means you can specify sixty four different things words i mean if you so in other words you can make sixty four different words with three letters where each letter can be out of alphabet of four and and the fact that multiple triplets like how big is a protein about three hundred amino acids just to have some numbers you had so a gene the part that codes for a protein is about a thousand bases because it's nine hundred because if you need to specify three hundred amino acids for a pro in other words it's five million of these letters but you need a thousand to specify a protein so now if all the d n a was genes five million divided by a thousand it's five thousand that's actually almost right you call it has about three or four thousand color actually all the d n a it's practically genes and this is true of all bacteria but then you get to higher forms of life and this falls apart in other words only a tiny fraction  the genome is the part that codes this is again something that's really curious that we don't understand why is it that in the sort of evolution of life all of a sudden big genomes emerge but these big genomes didn't make for lots more proteins ok in other words our genome is a thousand times bigger than the call i genome but we only have five times as many proteins so it looks like what what nature somehow managed to figure out is that somehow evolution went in this way in this direction of not making more lego parts but making more complicated instructions how to put those lego pieces together that seems to have  whether that's the only way to evolve more complex life forms we don't know and we'll probably only know when if if and when we find some other complex life forms on the side of this planet are there any theories for like there's just so stories there's a beautiful book by kipling called just so stories where he talks about how the leopard got its stripes and stuff like these are very cute stories that are nonsensical but fun and so there's lots of just so stories about these things so so  they're just so story in other words we don't know if this is true but it seems reasonable is that well the problem is as you well why the spacer d n a maybe because you want to have a very complicated control over this machine that reads the gene complicated meaning that it integrates many inputs to these proteins is actually in some sense detecting something in the cell or outside the cell and it's like you can think of these as little detectors and when all these detectors go on and off depending on how these detectors go on and off that determines whether a gene is red  you could try and put all those detectors right next to the to the gene and that's what he called that's what bacteria do in fact but then you can't put too many because there's just not enough room so the idea is the way that  life forms in complicated life forms the way that this got resolved is by putting these sort of elements further away and then and then sort of using this folding of the d n a to bring close together in other words their fur far away on the genes right this could be thousands of base pairs but then by the folding of the d n a they're brought enclosed space will produce so that to do that you need this kind of space or d n a yes maybe far so so here's the amusing thing so when it's injected into the cell now the cell sees there's d n a but the cell doesn't know that it has ways of trying to figure out that it's not its own d n a because inside a so they just go off and read the virus d n a ok and as they read the virus d n a what are they making they're making virus proteins whatever virus proteins they're proteins that actually make up this thing so in other words the virus just inject its d n a and then the cell just reads it it's like you know it's essentially like there needs there's this movies i think contact was one of them where aliens beam a message right and the message is blueprints for making some machine and then people busily you know start making that machine and then someone in the pentagon becomes the president says wait do we know that this much months we build that this machine just won't blow us to bits right how do we know this machine won't just kill us right that's exactly what the virus does it sends it just gives the cell the blueprint the d n a and the cell reads it and as it reads it it makes proteins these proteins assemble into a virus and boom all of a sudden you have a cell filled with viruses and they kill the