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Skip to 0 minutes and 15 seconds In this chapter we are going to see how the analysis of the genome may help us to trace back our past. So, the idea now is after having seen how we are in relation to other species, let’s see how we are in relation to ourselves, to humans by themselves. The first concept, to which extent the different humans are similar or different? Here is important not to relay on our own perception, because we are very used to see individuals similar to ourselves, and very much less to see different individuals. And, we may think that others are more similar among them than what really they are. How to deal with that? Again, looking at the genome.

Skip to 1 minute and 17 seconds So, what we have to do is to look at the genetic diversity of humans compared to other species.

Skip to 1 minute and 25 seconds In general, we could, if we have the genome of all ourselves or a single genome, my own genome for example, if I go along my genome, the question initially is: “Where is going to be a difference between my paternal and maternal genome?”.

Skip to 1 minute and 40 seconds And the answer to that is: “Around one every thousand base pairs”. So, my father and my mother where 99.9% similar between them. And this is the same as comparing my genome to the others genome. In general, we could say that the amount of difference between humans is 1 every 1000 base pairs. And here we have a very nice and interesting graph, in which we can see that humans are extremely, extremely similar among us. More, non-africans. Africans they have relativity high level of difference among the individuals, but non-africans is extremely low. And here we have the data comparing to the genomes of apes. And in this case you can see that humans are, let’s say, nearly clonal.

Skip to 2 minutes and 54 seconds The amount of difference we have among humans is much smaller than the amount of difference that we would find among chimps or among gorillas and, by far, among orangs. So, only, some populations, specific populations of bonobos and one of the subspecies of chimps, they have similar levels of genetic variations than humans. This means that we are very similar among us. Very similar among us. Small amount of variation. And why? The idea is very simple. Because we are a very young species, and we are going to see that the amount of variation is very, very small. So, in all the genetic analysis we have to work out long stretches of DNA to find differences.

Skip to 3 minutes and 52 seconds But we are lucky that we have technologies for doing that.

Origins of the humans. Part 1

We are very used to seeing individuals who are similar to ourselves and much less used to seeing individuals who are different, but what does genetics have to say about these differences?

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Why Biology Matters: The Genome and You

Pompeu Fabra University Barcelona