BG27

Question 1

History of human evolution

Answer 1

Richard owens - classified humans distinctly from other apes
- heiarhcy of brain morphology with humans at the top
Huxley darins champion wrote ‘mans place in nature’ which lay out our close relationship with chimps
- but claimed differences in hippocampus minor was distinct to humans

Question 2

Mcdonald Kreitman test

Answer 2

searched for the imprint of selection
Ka = no. of NS subs
Ks = no. of non synon subs

Question 3

ka/ks = 1
ka/ks <1
ka/ks > 1

Answer 3

ka/ks = 1 no selection
ka/ks <1 purifying selection
ka/ks > 1 positive selection

Question 4

Chimps vs humans

Answer 4

30 million nt differences identified from genome comparisons.
- overall rate of evo of chimp and human genes is found to be the same.

Question 5

mk for humans and chimps

Answer 5

mk humans = faster = 0.208
mk chimps = 0.194

** mice = 0.142

Question 6

orthologous genes, substitutions and positive selection in chimps and humans

Answer 6

13,454 orthologous genes
- sensory perception of chemcial stimulus 59 orthologs and high divergence = 0.018
~80% of subs in humans and chimps are deleterious
585 genes in humans are under positive selection have ka/ks>1

Question 7

KE family

Answer 7

travellers in britain with aphasia difficulties in learning, performing, complex orofacial movements and have receptve and expressioon deficits in oral and written language and grammer

Question 8

ke family mutation

Answer 8

mutation affects activity in Brocas area a entral language processing region

• mutation disrupts FOXP2 TF
• TF rapidly evolving in lineage leading to modern humans with 2 NS subs.

Question 9

rapidly evolving non-coding regions in humans and chimps

Answer 9

3500 regions of ncDNA with high homology between chimps, mice and rats
- of these 49 are human accelerated regions, HARs

Question 10

what is HAR1

Answer 10

a novel RNA 118bp long which contains 18 differences between humans and chimps but only 2 from chimp to chicken
it is expressed in the frontal cortex and hippocampus of adults
involved in neurogenesis.

Question 11

chuas

Answer 11

rat people of shua dulah
- small head, severe mental retardation.
legend = infertile woman give to shrine, first child born a chua.
- thought fabircated and instead heads are bound
however recently there were chuahs born in bradford in a family from punjab area, found high inbreeding within this family
pedigree shows cross linkage
high levels of first cousin marriage 30% in UK

Question 12

Microcephally

Answer 12

inherited recessive disorder

• one of 5 mutations
• mostly encoded centrosome, spindle fibre, microtubule protein
• microphalics are also small people, with smaller brains relative to size
• structural gene mutations seem to have stronger effect on brain.

Question 13

microcephaly genetics

Answer 13

MCPH-1 - 10,000 years old
and ASPM - 5000 years old

expressed during feotal brain development, certain mutations when homozygous cause primary micrcocephaly.

low freq in adrica high in erurope and asia

Question 14

MCPH and brain size

Answer 14

initial studies showed no association between mcph alleles and brain size in humans
- later studies found sex specificassociations with certain non-exonic SNPs.

driver of MCPH evolution in humans is not clear