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Anthropology > Evolutionary Genetics > Flashcards

Evolutionary Genetics Flashcards

(57 cards)

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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

Study These Flashcards
A

~ 120 ka => but not certain

24
Q

Orang Utans

Study These Flashcards
A

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

25
Fst value
Measure for genetic differentiation btw populations => high in chimps => low in humans
26
Multiregional model
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
Genetic divergence
If isolation => no geneflow
28
Out of Africa model
Modern H.sapiens evolved in africa and replaced H.erectus populations by spreading to europe and asia => extinction of H.erectus
29
Genetically most likely model of human evolution
Best demographic model is out of africa exponential replacement model
30
Homoplasy
Feature that has been gained/lost independently in diff lineages over the course of the evolution
31
Bottleneck/ founder event
Reduced genetic diversity Only small part of population left africa Also with mating => but sexual selection? Well certainly not natural selection
32
Hyper variable regions
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
Denisovans
Distal phalanx of finger => genetic legacy
34
Problem with DNA sequencing
Half life => jurassic parc completely wrong, DNA doesn't survive that long Contamination by other organisms
35
Geneflow btw neanderthals and modern humans
More from neanderthals to humans
36
Phylogenies
Always show only part of the picture => gene trees! Mt DNA might be different from nuclear DNA
37
Racist view
Hierarchy and falsification of skull shape
38
Linnaeus
Diurnus americanus, europaeus, asiaticus und afer Nocturnus
39
Concept of race
Imaginary categories that mix physical, intellectual and cultural characteristics
40
Taxonomic definition of race
Subspecies that are biologically distinct groups
41
Phenotypic plasticity
Same organism might have different phenotype in different environments
42
Hight difference between classes
Malnutrition
43
Short evolutionary time
Not enough generations to cause significant change in genes
44
Skin pigmentation
Dark skin Adaptation to UV radiation Eumelanin Light skin Pheomelanin => Vitamin D production => deficit leads to bone deformations
45
Single base pair mutations
Might be enough to disrupt signal cascadebresponsible for eumelanosome production => one single mutation can have drastic effects on phenotype
46
Genetic Variation
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
Effect size vs sample size
At large enough sample size, any difference can be significance But biologically relevant?
48
'Structure' algorithm analysis
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
Fst
0 = no genetic diversity btw pop 1 = completely gebetically diff
50
Genetic diversity in humans
Recent founder event => multiple events Diversity in humans is a gradient
51
Selective sweep
Fixation of a beneficial allele (frequency = 1) leads to reduction in genetic variation
52
Genetic surfing
Spatial spread of alleles that have not been lost by genetic drift
53
FOXP2
Already in Neanderthals
54
Nuclear DNA/full genome
Suggests common ancestor of Denisovans and Neanderthals to exclusion of humans
55
MtDNA
Suggests MRCA of humans and neanderthals to exclusion of denisovans
56
4 human population explosions
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
Pheomelanin
More abundant in Light skin Clusters in organelles

Anthropology (10 decks)

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