Evolutionary genomics II (DONE)

Question 1

What is speciation with gene flow?

Answer 1

Speciation that occurs while populations continue exchanging genetic material

Question 2

What is parapatry?

Answer 2

Speciation across adjacent populations w non-overlapping ranges & some gene flow

Question 3

What does Fst measure?

Answer 3

The proportions of genetic diversity due to allele freq differences among populations

Question 4

Why can high Fst values be misleading?

Answer 4

Peaks may result from reduced diversity within populations rather than the true divergence

Question 5

What occurs in stage 1 of speciation?

Answer 5

Divergence at one of few loci under strong disruptive selection

Question 6

How does divergence spread in later speciation stages?

Answer 6

Selection & reduced recombination spread divergence across the genome

Question 7

What are islands of divergence?

Answer 7

Genomic regions showing high differentiation, often due to selection

Question 8

What us hybridisation’s role in evolution?

Answer 8

It:

• Introduces genetic variation
• Fuels adaptive radiation
• Promotes phenotypic exchange

Question 9

What is adaptive introgression?

Answer 9

Gene flow that transfers beneficial alleles between species

Question 10

What do ABBA/BABA tests detect?

Answer 10

Patterns of introgression in hybridising pops

Question 11

How do Dobzhansky-Muller incompatibilities arise?

Answer 11

Thru negative interactions between genes from diff species

Question 12

Give an example of a genetic incompatibility in hybrid species?

Answer 12

Caudal melanoma in swordtail fishes (Xiphophorus melinche & X. birchmanni

Question 13

Why are species considered fluid?

Answer 13

Gene flow blurs boundaries & facilitates phenotypic exchange

Question 14

What does recombination do in genomic divergence?

Answer 14

It reshuffles alleles, reducing linkage disequilibrium & influencing selection

Question 15

How does gene flow influence speciation?

Answer 15

It promotes adaptive variation while maintaining some species identity

Question 16

What are the challenges of interpreting Fst?

Answer 16

Differentiating true selection from recombination or within population diversity

Question 17

Why is hybrid vigor?

Answer 17

Enhanced fitness in hybrids due to gene flow & genetic variation

Question 18

Why are subspecies important in early divergence?

Answer 18

They represent pops at stage I of speciation w localised genetic differences

Question 19

How does selection within pops resemble divergence between pops?

Answer 19

Selection reduces genetic variation, creating patterns similar to divergence

Question 20

What role does recombination play in hybrid genomes?

Answer 20

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

Question 21

How does gene flow facilitate adaptive radiation?

Answer 21

By introducing genetic diversity that allows rapid ecological specialisation

Question 22

Why is hybridisation more common than previously though?

Answer 22

Many species exch genetic material w/o losing their identities

Question 23

What is the impact of disruptive selection on speciation?

Answer 23

It drives divergence by favouring extreme phenotypes over intermediates

Question 24

How can gene flow maintain species identity?

Answer 24

By balancing the exchange of adaptive traits w reproductive barriers

Question 25

Why might islands of divergence be illusionary?

Answer 25

They can result from transient processes like gene flow rather than permanent barriers

Question 26

How do incomaptibilities contribute to speciation?

Answer 26

They create reproductive barriers that reinforce genetic divergence

Question 27

What is the significance of genomic scans in speciation studies?

Answer 27

They identify regions under selection that contribute to divergence

Question 28

What is the role of selection in genome evolution?

Answer 28

It promoted beneficial alleles while reducing neutral of deleterious variation

Question 29

How do polyphyletic species challenge traditional taxonomy?

Answer 29

They exchange useful genes across species, complicating boundaries

Question 30

What processes interact to change genomic patterns in speciation?

Answer 30

• Selection
• Gene flow
• Recombination
• Genetic drift