Human Genome Diversity Part 1
-text book pages will be posted
-contextual arFcles posted on portal
EvoluFon of the
X chromosome evolution
Human X consists of 155 Mb, ~3 Mb (2%) is
ampliconic sequence (i.e., segmental duplications of >
10 kb with > 99.9% identity)
<recall that 45% of Y euchromatic sequence is ampliconic>
Mouse X contains ~19 Mb (
1 sex chromosome
Why a sex chromosome?
Where did it come from?
Why do X and Y look so
Sex chromosomes are not necessary for separate sexes.
Sex can be deterimined by temperature (e.g., turtles).
Sex can be d
how do they evolve,
a GDL first emerges and then suppression of recombination occurs areound that GDL.
How might sex chromosomes evolve?
2. Reduced recombination evolves around gex determing
Human Genome Diversity Part 3
Describing Genomic Varia7on:
Signatures of Evolu7onary Forces
1) Amount of diversity- how much diversity
do we expect?
2) Allele frequencies
3) Linkage disequilibrium
4) Popula7on dieren7a7on
How Similar Are Human Popula'ons?
how different ?
is the genome really different in the same way we perceive populations differently or is
most of the genome the same across populations and are there just a few loci involve
Our closest kin
Protein evolution relative to neutral standard: KA/KS
Neutrality: KA = KS, so KA/KS = 1
Purifying (negative) selection results in slower
substitution rate at selected sites than neutral sites
KA/KS < 1