Lecture 2- Human evolutionary genomics

Question 1

why is mtDNA good for studying evolution within a species

Answer 1

high copy number per cell, high mutation rate, no recombination

Question 1

conclusions from male vs female studies

Answer 1

females seemed to move more- more isolation by distance in Y chromosomes compared to mt

Question 2

what is ‘MRCA’, and where does it lie for humans?

Answer 2

most recent common ancestor, the point at which no information is available about lineages before it. about 150k years ago

Question 3

other clades with which ancient humans may have interbred

Answer 3

neanderthals in europe, denisovians in asia

Question 4

why may skin colour have adapted between human lineages?

Answer 4

dark skin is useful for preventing DNA damage from UV, lighter skin allows for more D3 production where there is less sunlight, and there may be advantages in immunity etc

Question 5

wrt selective sweeps and diversity loss- where the recombination rate is lower…

Answer 5

selection at one gene will affect its neighbours more strongly

Question 6

example of local adaptation

Answer 6

lactase production, and continued ability to break down milk in areas with a lot of dairy farming

Question 7

what is FST?

Answer 7

fixation index- proportion of the total genetic variance within a subpopulation (S) as compared to the whole population (T)- values range from 0 to 1, where 1 is complete subdivision, and 0 is a panmimitic population

Question 8

example of adaptation at high altitudes

Answer 8

protection against hypoxia, ‘hypoxia inducible factor’- helped by the incorporation of other DNA