Evolutionary genomics I (DONE) Flashcards

1
Q

What is the focus of evolutionary genomics?

A

Understanding the genetic basis of phenotypic variation & how genetic variation shapes adaptation, speciation & evolution

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1
Q

What are the main processes shaping genomic variation?

A

Selection, gene flow & recombination

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2
Q

What are genome-wide association studies (GWAS)?

A

GWAS identify genetic variants associated w phenotypic traits across the genome

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3
Q

How do Manhattan plots help in GWAS?

A

They visualise the strength of association between genetic variants & phenotypic traits

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4
Q

What is the genetic basis of phenotypic variation in Darwin’s finches?

A

Variants influencing blunt vs pointed beaks, potentially linked to ancient alleles

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5
Q

What does “standing variation” mean?

A

Pre-existing genetic variation in a population that selection can act upon

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6
Q

What is a selective sweep?

A

A process where beneficial mutation rapidly increases in freq –> reducing genetic diversity near the locus

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7
Q

How do hard & soft selective sweeps differ?

A

Hard sweeps = involve new mutations

Soft sweeps = act on existing variation

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8
Q

What genomic signature indicated a selective sweep?

A
  • Reduced genetic diversity
  • Inc linkage disequilibrium
  • Higher differentiation from other pops
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9
Q

What study demonstrated habitat-driven genetic selection?

A

Deer mice (Peromyscus maniculatus) showing coat colour adaptation to their environment

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10
Q

What is genetic drift?

A

Random changes in allele frees, significant in small pops

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11
Q

What is gene flow?

A

Exchange of genetic material between pops, introducing variation

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12
Q

What is adaptive introgression?

A

Transfer of beneficial alleles between species through hybridisation

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13
Q

Give an example of adaptive introgression?

A

Snowshoe hares acquiring winter coat colour adaptation thru gene flow

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14
Q

What role does recombination play in genomic variation?

A

It reshuffles genetic material, breaking linkage disequilibrium & shaping genetic diversity

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15
Q

How does recombination influence gene flow?

A

It breaks down blocks of introgressed ancestry over time, facilitating adaptation

16
Q

Why are high recombination regions significant?

A

They often show greater introgression due to reduced linkage disequilibrium

17
Q

What did Cutter & Payseur (2013) conclude about recombination?

A

Recombination limits the extent of selection’s influence on genetic variants

18
Q

What confounds genomic data interpretation?

A
  • Overlapping influences of selection
  • Gene flow
  • Recombination
  • Environmental factors
19
Q

Why is it important to integrate genomic & ecological data?

A

To accurately identify drivers of adaptation & evolution

20
Q

What example links genomic data to phenotypic traits in birds?

A

Great tits: variants in COL4A5 are linked to bill length & reproductive success

21
Q

What does a genome scan reveal?

A

Genomic regions under selection & their associations w phenotypic traits

22
Q

What is phenotypic variation?

A

Observable differences in traits among individuals of a species

23
Q

Why are Mendelian traits easier to study than complex traits?

A

They are controlled by single genes, simplifying genetic associations

24
What role do ancient alleles play in evolution?
They can be reused across pops, contributing to standing variation
25
How does natural selection affect genetic diversity?
It reduces diversity near selected loci while favouring beneficial mutations
26
What is linkage disequilibrium?
The non-random association of alleles at different loci in a population
27
What is a key challenge in genomic studies?
Distinguishing the effects of selection from neutral evolutionary process
28
What is the importance of gene flow in adaptation?
It introduces novel genetic variation that can enhance survival in changing environments
29
What is the evolutionary significance of genomic tools?
They allow precise identification of genetic drivers of adaptation, speciation & biodiversity