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Welcome.
This is Human Migration
and Population Structure,
a lecture for a course in
Human Population Genetics.
My name is John Novembre from
the Department of Human Genetics
at the University of Chicago.
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The objectives for
this lecture are going
to be that we are going to introduce
theoretical models of population
structure.
We're going to talk
about how migration
drift and selection
impact genetic variation
in these structured populations.
Then, we are going to be
introducing tools for understanding
local population structure.
And finally, we'll finish with
a survey of spatial patterns
of genetic variation in humans.
A major theme throughout the lecture
is going to be the relationship
that genes and geography
have to one another
in complex models of
population structure.
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Some of the key ideas
that we're going to cover
are the genetic
consequences of population
structures being a balance of
mutation and genetic drift.
These are two forces that allow
populations to differentiate.
Genetic drift is the random
change in allele frequencies
due to finite population size.
And we'll see how those random
changes in allele frequencies
will lead to allele frequencies in
one population perhaps increasing,
in another population
perhaps decreasing.
And over time, that
leading to differentiation.
Gene flow, which is the exchange
of genes between populations
due to individuals migrating
between those populations,
is going to work as
a homogenizing force,
pulling those allele frequencies
that are differentiating from one
another back towards some
common mean allele frequency.
Less often, we think that there
are areas in the genome where
natural selection is acting
and differentiation can be
impacted by that natural selection.
So we'll also be talking
about adaptive evolution.
