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Anthropology > Evolutionary Genetics > Flashcards

Evolutionary Genetics Flashcards

1
Q

Wrong assumptions

A

Genetic diversity in humans is large compared to other great apes

Disease-causing alleles are specific to certain continental groups

Human phenotypes correlate with human genotypes

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2
Q

Biases in records

A

Archaeological => stone tools, no wooden tools
Paleontological => bones, no soft tissue
Genetic => survival is selective

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3
Q

Oldest fossil (primates)

A

Mid eocene

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4
Q

Last common ancestor of primates

A

80 MYA

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5
Q

Darwin and Huxley

A

Similarities btw humans and great apes
Humans should share genus homo with chimps and bonobos at least
=> subfamily

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6
Q

Chromosomal analyses

A

late prophase G-banding => stain

Human chromosome 2: fusion of 2 primate chromosomes

Orang Utans: pericentric inversion

Y chromosomes change faster bc no recombination => badly resolved

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7
Q

Common ancestor of humans and chimpanzees

A

5 to 6 Ma

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8
Q

Chimps and humans

A

High behavioral similarity

Group agression
Culture
Tool use

Differences

Bipedality
Brain size
Complex language

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9
Q

Are differences btw humans and chimps genetically canalized?

A

Similarity 96-98%
DNA-DNA hybridisation
Low melting temperature = not clearly related => low association
High mt = clearly rel.

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10
Q

Are genome differences functional?

A

If in coding regions or regulatory sequences

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11
Q

Whole genome shotgun

A

Create snippets of sequences, align them to known genome

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12
Q

Divergence in Y chromosome

A

Rapid evolution

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13
Q

Genes novel to humans

A

About 60 novel genes
Cerebral cortex => large brains and testes

Gene duplication: leads to more geene product
=> humans have much higher copy number of many genes

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14
Q

Important gene in diff chimps/humans

A

FOXP2 (forkhead domain genes)
=> TF

mutations => KE family => phenotype: language impairment => autosomal inheritance

Activation of neurons not concentrated to Broca’s area

Mutations could contribute to language => but does not have to be cause

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15
Q

FOXP2 knock out mice

A

Non-vocal Behavior not affected, only vocalizations

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16
Q

Microarray analysis

A

Blood amd liver expression patterns closer in humans and chimps than to macaques

But brain: chimps closer to macaques

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17
Q

Time shift in expression patterns

A

Delayed expression pattern in humans causes delayed development of brain

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18
Q

Handedness

A

Humans 9:1 prefer right hand
Chimps and other g. apes: no preference

Handedness mirrored in lateral asymmetry of sensory and motor regions of forebrain

=> neanderthals thought to be right handed => tools, art etc.
=> last common ancestor probably too

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19
Q

Asymmetric gene expression

A

Allelic expression of genes involved in hemispheric asymmetry
=> 27 genes with consistently hemispheric differences

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20
Q

What genetic changes have made us human?

A

• 1-2% sequence divergence
Heterochromatin changes
Retrotransposons
Duplications, deletions, point mutations
• most changes regulatory levels and expression patterns
• few gene function alterations

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21
Q

Divergence chimps and bonobos

A

River Kongo

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22
Q

Highest diversity in humans

A

In african populations => longer time of evolution

The further away from east africa, the lower the diversity

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23
Q

Time to MRCA

A

~ 120 ka => but not certain

24
Q

Orang Utans

A

Extremely philopatric => females basically never move => stay where they are born

25
Q

Fst value

A

Measure for genetic differentiation btw populations

=> high in chimps
=> low in humans

26
Q

Multiregional model

A

H. erectus dispersed from africa => at similar time settled in europe and asia => constant geneflow btw all thre groups

Anatomically modern H. sapiens genes arose in many populations

Assimilation of H.erectus

27
Q

Genetic divergence

A

If isolation => no geneflow

28
Q

Out of Africa model

A

Modern H.sapiens evolved in africa and replaced H.erectus populations by spreading to europe and asia => extinction of H.erectus

29
Q

Genetically most likely model of human evolution

A

Best demographic model is out of africa exponential replacement model

30
Q

Homoplasy

A

Feature that has been gained/lost independently in diff lineages over the course of the evolution

31
Q

Bottleneck/ founder event

A

Reduced genetic diversity

Only small part of population left africa

Also with mating => but sexual selection? Well certainly not natural selection

32
Q

Hyper variable regions

A

Due to homoplasy
=> fast occurring evolution
=> underestimation of difference

Mainly conquering males mated with neanderthal women => mtDNA no overlap in current humans, nuclear DNA looks different

33
Q

Denisovans

A

Distal phalanx of finger => genetic legacy

34
Q

Problem with DNA sequencing

A

Half life => jurassic parc completely wrong, DNA doesn’t survive that long
Contamination by other organisms

35
Q

Geneflow btw neanderthals and modern humans

A

More from neanderthals to humans

36
Q

Phylogenies

A

Always show only part of the picture => gene trees! Mt DNA might be different from nuclear DNA

37
Q

Racist view

A

Hierarchy and falsification of skull shape

38
Q

Linnaeus

A

Diurnus americanus, europaeus, asiaticus und afer

Nocturnus

39
Q

Concept of race

A

Imaginary categories that mix physical, intellectual and cultural characteristics

40
Q

Taxonomic definition of race

A

Subspecies that are biologically distinct groups

41
Q

Phenotypic plasticity

A

Same organism might have different phenotype in different environments

42
Q

Hight difference between classes

A

Malnutrition

43
Q

Short evolutionary time

A

Not enough generations to cause significant change in genes

44
Q

Skin pigmentation

A

Dark skin
Adaptation to UV radiation
Eumelanin

Light skin
Pheomelanin => Vitamin D production => deficit leads to bone deformations

45
Q

Single base pair mutations

A

Might be enough to disrupt signal cascadebresponsible for eumelanosome production

=> one single mutation can have drastic effects on phenotype

46
Q

Genetic Variation

A

In humans highest within populations
In other GAs btw populations

=> two europeans can genetically be more diff from each other than a european and an african

47
Q

Effect size vs sample size

A

At large enough sample size, any difference can be significance
But biologically relevant?

48
Q

‘Structure’ algorithm analysis

A

K2 = Africans, Europ, mid east, south asia more vs east asia, america, oceania
K3 = Africa vs Europe, mid east, south asia vs east asia, america, oceania
Etc.

=> even at high K europe, mid east, south asians are still in same cluster

49
Q

Fst

A

0 = no genetic diversity btw pop
1 = completely gebetically diff

50
Q

Genetic diversity in humans

A

Recent founder event => multiple events
Diversity in humans is a gradient

51
Q

Selective sweep

A

Fixation of a beneficial allele (frequency = 1) leads to reduction in genetic variation

52
Q

Genetic surfing

A

Spatial spread of alleles that have not been lost by genetic drift

53
Q

FOXP2

A

Already in Neanderthals

54
Q

Nuclear DNA/full genome

A

Suggests common ancestor of Denisovans and Neanderthals to exclusion of humans

55
Q

MtDNA

A

Suggests MRCA of humans and neanderthals to exclusion of denisovans

56
Q

4 human population explosions

A

100’000 years: first expansion
11’000-5’000 years: agriculture
5’000-500 years: domestication of horse and military inventions
500 years: industrialization

57
Q

Pheomelanin

A

More abundant in Light skin
Clusters in organelles

Anthropology (10 decks)

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