BIOLOGY 1M03 Lecture Notes - Lecture 8: Melanosome, Introgression, Cholecalciferol
29 Jun 2018
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This figure is based on 277 people
looking at their mitochondrial DNA
sequence. Idea is that because we can
go back to eve with regard to
mitochondrial DNA and because we
don’t have crossing over we can look at
sequences and we can arrange these
277 individuals into a phylogenetic tree
such that the deeper the nodes, the
further back these various plates go
and you can see that these first labelled
L1 are made up of people from Africa,
next group, L2, are made up of Africans
and so are L3. M and N are
progressively getting more and more recent. Phylogeny supports our out of Africa,
deepest clads are African.
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find more resources at oneclass.com
Now if we look at what was going on in terms of movement. Starts with 150000
years ago, L1 were established and you can see it moving out to different parts of
Africa. Skip ahead to 60-80 thousand years ago, L1 has given way to L2 and L3. L2
and L3 are different clads, there have been mutations and those have been
propagated into different clads and we can separate them and tell them apart from
different sequences. L2 and L3 dispersed in Africa and L1 diminished in numbers.
50-60 thousand years ago, L3 has lead to mutations that led to N and M. N and M
are most closely related to l#. These are the groups that left Africa and started to
move out and move through Asia and from there we have further movements into
Europe and Northern Asia. Eventually to North America. During this period, we se
signs of Neanderthal introgression, we are seeing mitochondrial DNA and some
sequence from genomic sequence getting into our DNA. Neanderthal slipping into
homo sapiens. Subsequent to that, Denosovian people, also introgrossed DNA into
human DNA. We can still see stamps from people in that area. We were established
in Africa, initially clads mutated and produced other clads. Other clads then led to
other clads. Those clads came out of Africa and spread throughout the world
eventually.
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
This figure is based on 277 people looking at their mitochondrial dna sequence. Idea is that because we can go back to eve with regard to mitochondrial dna and because we don"t have crossing over we can look at sequences and we can arrange these. 277 individuals into a phylogenetic tree such that the deeper the nodes, the further back these various plates go and you can see that these first labelled. L1 are made up of people from africa, next group, l2, are made up of africans and so are l3. M and n are progressively getting more and more recent. Phylogeny supports our out of africa, deepest clads are african. Now if we look at what was going on in terms of movement. Starts with 150000 years ago, l1 were established and you can see it moving out to different parts of. Skip ahead to 60-80 thousand years ago, l1 has given way to l2 and l3.
