What DNA Says About Our Human Family Episode II, Ancient Relatives: Neanderthals and Denisovans

hi I'm Dave McClure's I'm here at the Hall of human origins at the DNA Learning Center of Cold Spring Harbor Laboratory and I'd like to welcome you to the second episode of our series what DNA has to say about our human family today we're going to be looking at ancient ancestors particularly Homo erectus the Neanderthals and the Denisovans but before I get started on today's exploration I need to go back in time and fill you in a little bit about what we did yesterday for those of you that were here in the previous session it would be a review but for those tuning in for the first time this is essential information we started our exploration the other day by asking the question which animal has greater genetic diversity chimpanzees or humans and we said that in order to answer that question we would have to use DNA as a sort of molecular clock to go forward and backward in time and the basic idea that we need to know is that the DNA molecule which have a simple representation of here can be changed by process called mutation and basically what happens in the mutation process is that these rungs of the DNA ladders can be changed so for example this orange rung here which represents the chemical cytosine could change into say this blue one here which represents thymine so changes can occur to the four rungs of the DNA ladder that make up the sequence of DNA the key thing to understand is that mutations in DNA happen one at a time not all at once they happen at a more or less constant rate over evolutionary time and so that over time mutations in DNA accumulate and we can count the number of differences in mutations between different organisms or different individuals and the fewer the mutations between any two individuals or groups the more closely related they are more mutations that you can count between the DNA of two different groups the more distantly related they are we also introduced the concept of the DNA lineage where you have the progenitor of this lineage at the top in white and then going down in each generation there may be a change where the white DNA that we began with encounters a change such as the red that you see on the left or the blue and green and yellows that you see on the right as you go through time and look and sample the DNA which is represented by the line present time you can actually see a record of the mutations that occurred over time so for example in the red and the white line you can see those two mutations in the twisted pipe cleaner and on the other side you can see the several mutations that occurred green to yellow twisted together in that pipe cleaner there's different ways that we can study DNA diversity many people are familiar with the nucleus of the DNA nucleus of the cell which contains most of our DNA but the compartments outside the nucleus called the mitochondria also have their own DNA and in many cases it's easier to study the mitochondria are the powerhouses of the cell they make the energy that's needed for the cell to carry on life processes there's thousands of them per cell so it's a rich source of DNA because they have their own DNA that's shaped like a circle I another thing that I didn't emphasize in the last session but I'll emphasize now is that mitochondrial DNA is inherited only through your mother's line that's really great because that means it doesn't recombine or mix up with any male DNA and it represents a clean more or less pure line of descent from mother to daughter to mother to daughter and here's how it works when this firm encounters an egg cell and fertilizes it none of the sperm cell DNA enters the egg however the DNA sequence of the mitochondria is passed on from cell to cell and you can see in this lineage where females are circles and males are squares that the DNA has passed in a lineage from grandmother to child to child and you'll see that the male offspring of this mother carries his mother's mitochondrial DNA but does not carry it forward in time in his lineage and by the same token this male that comes outside of the lineage does not bring DNA into the lineage so that you can trace this lineage of mitochondrial DNA from grandmother to daughter to child I also told you that finding the DNA to do a mitochondrial DNA analysis it's really quite simple we can rinse our mouth out with saline solution or take a swab with a q-tip and that will give us some squamous cells that you'll see in pink there which are a fine source of mitochondrial DNA and the hundreds of cells that we obtained that way are amplified by a process called PCR which we went over a little bit yesterday on the other day and then finally they're sent off for DNA sequencing where the sequence of the DNA ladder rungs are determined precisely the sequence of a t c's and g's those sequences come back to a tool that we have online called bio servers which is a simple bioinformatics tool and then we can analyze the DNA and remember that what we did was we display to the sequence of two different living humans in this case someone from Germany and Japan and we just compared in a row the sequence of their mitochondrial DNA wherever the DNA is the same you'll see a T here and a T here a T here and a T here but where there's a difference between the two sequence sequences it's highlighted in yellow so in this case the German sequence has a T whereas the Japanese sequence has a C and we can count the number of differences over a stretch of mitochondrial DNA about four hundred rungs of the DNA ladder long and we can compare them also to chimpanzees and what we notice is that the average number of difference between any two modern humans was about seven and the average number of differences between any two chimpanzees throughout their range was about thirty so we concluded that there is much more genetic diversity in chimpanzees than in modern humans and here's a complicated tree where the great-great great-great grandmother of this whole lineage is here and at the branch of each branch of the tree is one individual either a chimpanzee or a human and you can see there were thousands of humans and chimpanzees in this study and if we label it will see that all the groups of chimpanzees from across the belt of Equatorial Africa represent most of the variation in this tree and modern humans represent only this small fraction we mentioned that when Africa when the African climate dried out about two million years ago the rainforests across Central Averett Africa was fragmented into the current groups of rainforests that you see here and where the chimpanzees currently live japansese spend most of their times in the trees but they do come down to the land at times and when Africa dried out several million years ago Great Plains and grasslands opened up habitat for many many new animals including our forebears who most certainly evolved in Africa and those are the four bears that we'll talk about at the beginning today the big question has always been if modern humans arose from ancient ancestors in Africa and there's lots and lots of anthropological evidence skulls of many of our forebears are found throughout Africa it's clear we came from there but when did our ancestors leave Africa and populate the rest of the world in particular when did they get to Asia in Europe which would consider the old world and we know the new world the Americas was populated much much later so the question is when did our ancestors leave Africa well here's a representative of who we are now Homo sapiens and we know that from anthropological bone evidence and other evidence tools that modern humans came into being about 300,000 years ago and the earliest evidence comes in fact from North Africa of modern humans Homo sapiens but a key figure in our ancient ancestor II is Homo erectus it's very clear that homo erectus or it's very near relatives where our direct ancestors and they came into being about two and a half million years ago and then went extinct somewhere about 200,000 years ago or perhaps they came forward even more into time but it's not clear so homo erectus arose in Africa and another ancient ancestor that has really fired the imagination of humans for a long time as Neanderthal it lived from about 600,000 years ago and became extinct about 35,000 years ago so a key question has been were the Neanderthals ancestors of modern humans living today and part of the reason why that was such a compelling question is the remains of Neanderthals and their habitations can be found throughout Europe and into Western Asia and here we have the range of the Neanderthals the maps a little unclear but here we are Spain here England across France and over into Turkey and also into Western Russia so Neanderthal ranged widely throughout Europe during its time and went extinct about 35,000 years ago so it was very plausible that Neanderthal could have been the ancestor of modern humans especially living in Europe today now behind me is in the under tall skeleton on the left and a modern human skeleton on the right they look pretty similar the Neanderthals were pretty tall they had bigger ribcage which is the which we think was made them adapted for cold climates they had relatively heavy bones but the key thing is if you look at their skulls the Neanderthal in my left hand and the modern human in my right you'll see that Neanderthals had big skulls meaning big brains as a matter of fact the average human brain if you filled up this space here this sort of oblong space the average human brain the average Neanderthal brain was in fact a little bigger than the brains that we have so the key thing is if a big brain means more or less the to do things and to reason and to think Neanderthals had quite a good capability to do probably many of the things that we do today brain wise well there are set there especially up until recent times they were competing theories about when our ancestors left after Africa and it led to opposing theories of human evolution I'm going to run through the two prevalent ones and then we're going to do actually a test of those two theories with DNA remember a central figure in all of these animations that I'm going to show you is Homo erectus he was clearly an ancient ancestor of ours who originated in Africa and you're going to see Wayne ranged widely across the globe so here's how more erectus originating in Africa coming out of Africa about a million and a half years ago and populating parts of the ancient world in Asia and up into Europe and all of this occurred hundreds of thousands of years ago so Homo erectus was very successful at walking around he was the upright man and woman they migrated out of africa into many parts of the old world europe and asia now one theory says that Homo erectus all this happened with Homo erectus so there's Homo erectus and one theory which is called the multi-regional hypothesis suggests that modern humans arose from the homo erectus people that were already there in antiquity so homo erectus came out of Africa hundreds of thousands of years ago and modern humans underwent a sort of parallel evolution where different groups in Europe and Asia arose from the ancient homo erectus stalks so that's one theory which is called the multi-regional hypothesis now totally different theory agrees that homo erectus was there sorry I didn't advance my slide let's try the next one so the third theory agrees that Homo erectus was in the ancient world in ancient times but a second group emerged from Africa much later about 60,000 years ago and then went into Europe and Asia and ultimately across into the new world the key thing is is the timing in this proposal which is sometimes called Out of Africa or the recent African origin key thing here Homo erectus did come out of Africa hundreds of thousands of years ago but a much more recent group that where our ancestors came out of Africa just about 60 thousand years ago and the question is how could you ever figure out which of these two theories might be right and the answer is you can look to DNA the first key experiment that really started to answer the question between these two competing theories was done in 1997 by Svante Paabo who is now at the Max Planck Institute for evolutionary anthropology he he was the first to obtain a mitochondrial DNA sequence from a Neanderthal bone and it was actually from the type specimen the original specimen collected of Neanderthal from the Neander Valley in Germany so first he had to do an experiment just like the one we did in the previous session which was the tert to determine what's the extent of modern DNA diversity and then how does Neanderthal fit into it so what I'd like to do now is to work on DNA lineage as we did before let's go back to the bioinformatics tools I'll go online now and do this analysis in real time with you we're going to repeat some of our work from the previous session so I'm going to enter this facility called sequence server I'm going to collect DNA by going up here into manage groups and I'm going to work with some DNA as some students who looked at their mitochondrial DNA about a month ago and I just need to find this person I always have trouble finding this person there we go Edmonds Community College outside of Seattle so I'm going to move their DNA samples I'll zoom into this just to give you a little better view of things first I need to so what I'm going to do is compare any two students from this class in outside of Seattle so here's student number one and here student number two I aligned their DNA and what you'll see is on one line as student number one there's 50 nucleotides of sequence and here's student number 2 so you can see where their DNA is perfectly matching or perfectly aligned there's no difference is here I can zoom in I have to be careful with the zoom because it doesn't work well on the other page but if i zoom in now what you'll see is I can go through the sequence here this doesn't count this is sort of nonsense when I come into the sequence and I can see that between student 1 and 2 there's one difference and the sequence ends down here these ends means that it can't be determined let's compare another pair which is student number 1 versus student number 4 go into the alignment and again look for the differences and I see one two three differences and if I compare another student here bringing another student student 5 as compare student 5 to student 1 I see one two three four differences before I hit near to the end and I'll just do one more sample I'll do student number seven versus student number five so I have three there so let's get rid of that one and I count one two three four five six seven eight nine ten eleven twelve differences so what you can see is there's a very variable number of differences between any two students and I can go into the database very quickly and pull up some other samples from a database and what I'm going to just pull up is some modern human DNA and I'm just going to take Africa and Asia just and Europeans for starters I'll move them into the workspace and now I'll quickly compare student number five versus someone from Greece again I come into the sequence and I count one two three four differences I'll do a student number five versus someone from Japan come into the sequence one two three four five differences and I'll just do one more I'll do student number one versus a Kung Bushmen of the Kalahari Desert of Southern Africa and I count one two three four five six seven eight nine ten eleven twelve well what's fun Pabu did in the original research was to do about a thousand pairs of modern humans I did you can see seven or eight but imagine doing that a thousand times and he found that the average numbers number of differences between any two living humans today was about seven and you can see that that was the range that we came up with between 1 and 12 and we would have if we did this even over just twenty or thirty sequences we would come very close to that average of seven so the key thing is is that seven equals the extent of the variation that accumulated in modern humans since we arose about three hundred thousand years ago so seven mutations on average between any two people equal about three hundred thousand years of evolutionary time so now we ask the next question which is how about Neanderthal and we had sequences from Neanderthal beginning in the 1990s the first done by Svante Paabo and then additional ones came on board so all I need to do now is to bring Neanderthal in to this so I'll go into the database I've got to just zoom out here for this I'll come into the database and I'll look for Neanderthal mitochondrial DNA we have a whole set of it there's a you can see seven or eight sequences there's new ones all the time but we have a few there I'm going to move a few of them into the workspace here's the original one from from Germany here's one from Russia and I'm going to take also one from Spain so I've just taken three different Neanderthals maybe I'll take a couple more just in case I want them okay so now I've become a little more complicated here because they have several things on my workspace but let's get rid of the Kong Bushmen and let's compare here's our student from Edmonds Community College student 5 let's stick with that one and let's compare student number 5 to the original Neanderthal sequence let's come into the sequence here zoom in a little bit and let's count the number of differences 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 let's do that Neanderthal versus another student student number one same analysis zoom in a little bit and let's count the number of mutations 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 and let's pull a different Neanderthal in now let's do one coming from the Caucasus in Russia vs. student number 5 one two three four five six seven eight nine 10 11 12 13 14 15 16 17 18 19 20 21 22 23 okay again we could do more and more pairs of a Neanderthal and a modern human and build more and more data but the data would tell pretty much the same story which is theirs on the order of 25 or 30 or 35 differences between any modern human and any of our Neanderthal samples so what does this mean let's come back to our slides for a second Oh what about Otzi the Iceman maybe you can just pan we have a model of Otzi the Iceman right in the room here with me camera man is not happy about this but there's ought to the Iceman he's about five thousand years old a mummy found in the Tyrolean Alps of Europe and the question is what about Otzi the Iceman how many differences would we see between Otzi's DNA and ours we can do that experiment too if we just come back one more time and add him in so if I come into I should have at C's sequence here I should have pulled him over earlier but somewhere on here is odd see there he is okay so now I move Otzi over into the workplace and let's just what would you think about Otzi he's 5000 years old really look like a modern human or will he look more like the Neanderthal sequence let's think about that but let's do it here's Otzi versus a student number five from Seattle and if we take a look here student number five and Otzi one two three four let's just do one more let's do at C versus the Japanese person just to cement this here's Otzi versus someone from Japan one two three four five so remember we said the average human variation between modern humans is somewhere around seven and you'll see that we came up in that range when we compared modern humans to ought see well it shouldn't come any surprise but five thousand years is no time in DNA time so oxy is fully modern his DNA his Anatomy the diseases he had the problems he suffered we're all pretty much the same ones we had with the possible exception of kovat so let's do one more analysis here and then come back to our theories of evolution this is another way of analyzing DNA it's a different bioinformatics tool that we made here it's called DNA subway now what I'm going to do here is start a little project on ancient DNA and I'm going to tell it that I'm working with mitochondrial DNA and what I'm going to do is I'm going to bring in that class from Seattle again so I just have to come into the sequences here and find it I believe it's on page three there it is right here Lazarus Hart Edmonds Community College so what I'll do is I'm not going to take all of the sequences but I'm going to take several student sequences and I'm going to add them to my DNA analysis project and then I'm going to start this project well I think I'm also going to take some okay I actually took a different set but that's fine now let's let's just start over one more time here ancient DNA I'm going to take the sequences again from Seattle I'm going to select just several of the student sequences I'm going to add them to the project and now I'm just going to create this project okay now I'm going to add to the project some Neanderthal sequences to do that I have to come into the boy if to do just one step there now I'm going to add some reference data and here I have some different data I'm not going to use it all but I'm going to take some of it I'm going to take some African sequence sequences I'm going to take some Asian sequences and I'm going to take some European sequences and I'm going to take some ancient sequences great now what I'd like to do is build a tree I've showed you some hypothetical trees made out of pipe cleaners but let me show you a real DNA tree made with DNA data so I'm just going to come in to the data that I've assessed or amassed here and here are the student samples from Seattle and I'm going to take all of them in the analysis I'm going to take some modern human samples from Asia I'm just going to take two because it can become a little bit crowded if I do too much but there's a sample from China and one from Korea I'm going to take a couple of the Neanderthal samples I'm going to take at sea I'm going to take a European a couple of Europeans I'm going to take it from England and Iceland and I'm going to take two Africans one your Reuben from West Africa and one Algerian from North Africa so now I'll save those samples that I've put into my analysis and now I'm going to do a sequence alignment like we saw in the bio server tool but it's in a different tool and it has an entirely different look I think you'll like it it's a little more complicated but it's also in color so now I have an alignment between all of my samples here here are the samples here and here's the DNA it looks a bit weird because you'll see these big blocks here and what these big blocks mean that there's no sequence in those samples some samples have a very long sequence like this and some have much shorter as if in effect this Chinese sequence is so short that it's cutting off some sequence we can use because you see I could use all of this sequence except the Chinese one so I'm going to actually go back and kick that one out of the analysis because it will make things clearer so I'm just going to now resave it realign the DNA - the Chinese sample which just happened to be a shorter one and now I can view this good now what I need to do in order to build a tree all of the sequences have to be of an identical length because otherwise the algorithm that makes a tree will start interpreting these Nothingness as differences so what I'll do now is just trim all of these aligned sequence is to get the central part where they're all where they all have sequence and now you see it's a much shorter sequence I can zoom in and you can take a look at it and and what you see here are the DNA mutations that are different from person to person you can see some sort of patterns like here's the Neanderthals down here and you'll notice they have a sort of a different looking barcode almost like the barcodes you see in a grocery store and the group's up here the modern they have certain affinities also but watch when we now make a tree out of these data so the algorithm will go through and interpret the relationships and interpret them as mutations happening happening one at a time as we mentioned before and then how could of those mean how can we account for those mutations with a tree going back in time and here it is it will build it very quickly and I just have to set one thing here which is I just have to make the tree do something here actually that didn't really help very much so let's just try one more okay so now here we have a tree and it's not a perfect tree but what you'll see here's the ancestor of all of the females in who are in this analysis of all of the mitochondrial DNA that's in this analysis here's the ancestor going way back in time and then each time you can see there's a branch the key thing I want you to see here is that all of these branches here are separate and they are all Neanderthals and then the human part of the tree comes down here so as we said in a simple way the number of mutations that we saw between the modern human and in Neanderthal 20 or 30 was outside of the variation of modern humans in other words Neanderthal cannot be a direct ancestor of modern humans otherwise near too-tall would be within the variation that we have in other words Neanderthal would be within this part of the tree if we were related to him because you can see all the other modern humans are grouped together so what this says to us is that the multi-regional hypothesis we're ancient people in Europe including the and earth all gave rise to modern Europeans and perhaps Asians cannot be correct according to this analysis because according to this analysis Neanderthal is outside of the genetic variation that is shared by other modern humans so Neanderthal couldn't have been directly related to us but certainly is a cousin and we certainly share an ancestor far back in time well we have two more analyses that we'll try to do today well the number of mutations that separate humans and Neanderthals it's actually if you do it fastidiously it's about 28 how many years does that equal well DNA time isn't exactly correlate very well with paleo paleontological time or what the bones say but roughly we think that if this is humans here and these are Neanderthals that we shared a common ancestor about 600 thousands and 900 thousand years ago so there we go 28 here's the Neanderthals branching off from modern humans we had an ancestor farther back in time and it was about 600,000 years ago there is a cave in southern severe Siberia called the Denisova cave and many Neanderthal remains had come from that cave as a matter of fact we might have an analyzed some of the mitochondrial DNA from one of the Dennis ofin Neanderthals during the dig there they found lots of remains not just whole skeletons including they found this tooth and they did analysis on this tooth and one other tooth and one other bone eventually and were surprised that the sequence didn't match Neanderthal and so in fact there was another ancient human mixed up in the remains in the Denisova cave so let's take a look and analyze that DNA and see what it has to say about where it is in this whole mess of human evolution so to do is come back to this analysis here remember here's the DNA subway I just need to go into the reference data again oh I think you actually it's there I'm going to come into the Select data here and I think that Denisova is here already there it is there's two sequences one from a tooth like the one I showed you and one from a bone I'll just take the tooths and such what that's what we looked at and I'm going to add now the Denisova DNA to our analysis do the same thing the multiple sequence alignment which will align all of the DNA sequences that we've analyzed there they're all aligned I just need to trim these outside areas and there's the sequence and you can see the differences the mutation differences between all the different organisms and now let's make a tree this tree I'm going to make the Denisovans sort of as the what's called the out-group of the tree and now let's take a look it actually makes a really beautiful tree because to make the best kind of tree you need something that's distantly related to everything else and in this case the Denisovans what you'll see is that the Denisovans separated first from this whole lineage so here's the great-great-great thousands of times grandmother of this group the Denisovans come off and we believe that we shared a common ancestor with the dennis de mis events about a million or 1.2 million years ago here's the Neanderthal sequences all clustered together beautifully as you would expect and then here's all the modern human sequences including the students from Seattle here here here and here this is about the same tree that you would see in a textbook because it clearly shows that the Denisovans were another ancient ancestor separate from the Neanderthal that goes back further in evolutionary time to a common ancestor and then of course if we go back this lineage far enough we'll come to homo erectus in Africa I have one more kind of analysis oh and here's a tree that I put in a book it's a slightly outdated but it's pretty identical to the one that we generated using the data and the key thing I want you to see here is that there's now good evidence that there was mixing of DNA between Neanderthals and modern humans and even between Denison and modern humans about several percent of the DNA of any person is derived from the Denisovans or the Neanderthals and we can find that vial informatica Lee the final thing I want to leave you with is an entirely different analysis it's out of the range mainstream of what we've been showing today which is how did humans evolve and move across the world this one this one is an experiment that everyone does but it gets at this question of my late friend Marcello's Ennis calcio which is knowing that we have a shared ancestry is the best inoculation against racism and let me show you how this works by doing one final set of experiments what I didn't tell you is that if we sequence your mitochondrial DNA and you do this experiment I'm just going to get rid of some of this and you do this same experiment and you have some classmates or some family members or whatever what do you think is the first experiment that you'll do if you have your own mitochondrial DNA sequence you're exactly right you're going to compare it to people who you think are like you maybe your friends in your group maybe your family members so let's just sort of do this by going back into the database I just cleared this workspace off to make it simpler let's just got a zoom out here for a second so let's come in and get our class again from Edmonds Community College and let's also get African samples oh I didn't move them sorry let's try again okay so remember I said that the first thing someone in this class is likely to do is compare it to their friend and let's say that person one and two are friends and they're going to compare their DNA and they're going to see that there's just one or two differences after a while they get tired most people will get tired of comparing DNA to the people who seem like them or who are friends with them and they'll branch out and do other things and what I want to do is show you something that's very paradoxical I can't be sure but I'm assuming that probably these students are Caucasian now if we're not exactly sure it doesn't matter the key thing is is that they're here in the United States and they're not in Africa so let's take now what I'm going to do is take two African samples I'm going to take a urine and a condom Bushmen so that's a person from West Africa and a person from southern Africa and I'm going to compare them to the student sorry I didn't click them all off I'm doing a three-way comparison now now when you do a three-way comparison at any position two of the people will have the same sequence and one will be different and so what I want to do is to take a look at this now what you might expect is that where where there's a difference that the year that the person the student from Seattle would be different from either one of these two Africans that's my hypothesis and I would guess it would be the high possible by hypothesis of that student but let's see if that's the case so in each case we're going to say who is the same and who's different at that position so at this first position the student is the same as the calm Bushman and the you Reuben is different in this case the student is the same as the yoruba n-- and the cun is different here's the student and the Aruban the student and the yoruba n-- the student and the Aruban the student and the Aruban here's a case where the two Africans match but here again student and the Yoruba n-- the two Africans come and the student the Yoruba and the student through Reuben and the student and the year Reuben and the student so out of about ten places the student matched with one or the other of the Africans more often than the Africans matched each other by a long way now you can do the opposite of this which is you can take two students and one African and do the inverse of this this might in fact be have been the first thing that might have been tried so again we're looking at who which two are the same and which two are different at the first position the students are the same in the second position the students are the same in the third position the student interieur Reuben in the fourth position the students are the same so in that case the students were more similar however if I take perhaps another student or if I take another African I'll get a slightly different story so this sequence isn't quite as good but in this case I have the Algerian and one of the students the Algerian and one of the students the Algerian and one of the students the Algerian and one of the students so again I wish that I knew exactly the background of the students but the point I want to make to you here is especially when you do the experiment with two Africans and a non African so let's just try the Algerian or let's even try to come Bushmen and student number six so here's two people from the same group in Africa and what you'll see is that they're very closely related and in fact the to come Bushmen in this case have the affinity with each other most of the time all of the time so the point I want to make is that when you do these comparisons you can never know exactly what to expect but very often if you compare a person of European or Asian ancestry with two Africans you'll actually find the two Africans are different at a position from the Asian or the European and what we're seeing here is that in Africa where we arose the populations of humans were quite large throughout our history the diversity continued to develop there throughout that time and that we see the greatest diversity among African populations and what we see in general that the mutations that we have in Europe and in Asia are a subset of the mutations in Africa and the reason for that is the ancestors of modern a and modern Europeans and everyone else came out of Africa and when they did on those small migrations they pulled out some of the diversity that was in Africa and took it with them to different places around the globe so I hope that you've enjoyed this analysis I hope you have an idea about where modern humans came from how we evolved from ancient hominids like Homo erectus and how we're related to Neanderthal and the dissidents and if you join me in the next installment on Friday I'll talk to you about human populations we'll look at a different genetic system and a different mutation and what it has to say about our human family

Channel: DNA Learning Center

Views: 154,697

Rating: 4.7013617 out of 5

Keywords: Human origins, human evolution, genetic diversity, bioinformatics, DNA sequencing, DNA sequence alignment, mitochondrial DNA, mtDNA, human-chimpanzee DNA sequence comparison, David Micklos, DNA Learning Center, Cold Spring Harbor Laboratory, Neanderthals, Denisovans

Id: pkLCAJAirvE

Length: 57min 23sec (3443 seconds)

Published: Wed Apr 01 2020