Podcast
Questions and Answers
What is one proposed explanation for Haldane’s Rule regarding hybrid sterility in Drosophila?
What is one proposed explanation for Haldane’s Rule regarding hybrid sterility in Drosophila?
- Increased gene flow between species.
- Chromosomal rearrangements are dominant in hybrids.
- X-A incompatibilities in the heterogametic sex. (correct)
- Environmental factors leading to hybrid invulnerability.
Which genes in Drosophila are associated with species incompatibility and show evidence of adaptive protein evolution?
Which genes in Drosophila are associated with species incompatibility and show evidence of adaptive protein evolution?
- Ods, Hmr, Nup96, and Nup160. (correct)
- Dscam and Dicer.
- Brd and Gpdh.
- Ftz and Ubx.
What might be a consequence of ongoing genomic conflicts in hybrid Drosophila?
What might be a consequence of ongoing genomic conflicts in hybrid Drosophila?
- Speciation through sex-ratio meiotic drive. (correct)
- Reduced introgression patterns between species.
- Enhanced genetic diversity among populations.
- Increased fertility and viability of hybrids.
What type of introgressions are indicated by red triangles in the sechellia genome model?
What type of introgressions are indicated by red triangles in the sechellia genome model?
What role do the genes related to hybrid male sterility play in the context of Drosophila evolution?
What role do the genes related to hybrid male sterility play in the context of Drosophila evolution?
What is a potential outcome of the hybridization between G.conirostris and G.fortis in Galapagos finches?
What is a potential outcome of the hybridization between G.conirostris and G.fortis in Galapagos finches?
How can strong selection affect species maintenance despite gene flow?
How can strong selection affect species maintenance despite gene flow?
What does the presence of patterns of introgression across hybrid zones indicate?
What does the presence of patterns of introgression across hybrid zones indicate?
What is still unclear regarding speciation with gene flow compared to strict allopatry?
What is still unclear regarding speciation with gene flow compared to strict allopatry?
Which mechanism allows favored alleles to move through hybridization events?
Which mechanism allows favored alleles to move through hybridization events?
In the context of hybrid speciation, what does imprinting refer to?
In the context of hybrid speciation, what does imprinting refer to?
What can be inferred about the success of hybridization events?
What can be inferred about the success of hybridization events?
What does the term 'speciation with gene flow' imply?
What does the term 'speciation with gene flow' imply?
What is a significant factor contributing to the rapid speciation in plants?
What is a significant factor contributing to the rapid speciation in plants?
Which organism is known for having speciation rates that may be slower compared to cichlids?
Which organism is known for having speciation rates that may be slower compared to cichlids?
What is the consequence of crossing tetraploid plants with diploids?
What is the consequence of crossing tetraploid plants with diploids?
What does the 'large X-effect' refer to in Drosophila hybrids?
What does the 'large X-effect' refer to in Drosophila hybrids?
What mechanism can facilitate polyploid speciation in plants?
What mechanism can facilitate polyploid speciation in plants?
Which of these is NOT associated with speciation rates in the mentioned organisms?
Which of these is NOT associated with speciation rates in the mentioned organisms?
Which of the following refers specifically to hybridization resulting in a new species with an increased chromosome count?
Which of the following refers specifically to hybridization resulting in a new species with an increased chromosome count?
Which statement about tetraploid mint Galeopsis tetrahit is accurate?
Which statement about tetraploid mint Galeopsis tetrahit is accurate?
Flashcards
Haldane's Rule
Haldane's Rule
A rule in genetics stating that, in interspecies hybrids, the sex most often affected by sterility is the heterogametic sex (e.g., male in mammals and flies).
Drosophila species incompatibility
Drosophila species incompatibility
Genes like Ods, Hmr, Nup96, and Nup160 are involved in reproductive isolation between different Drosophila species, potentially through adaptive protein evolution.
Hybrid Male Sterility
Hybrid Male Sterility
Sterility in male offspring resulting from mating between different species.
Adaptive protein evolution
Adaptive protein evolution
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Sex-ratio meiotic drive
Sex-ratio meiotic drive
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Speciation time variation
Speciation time variation
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Lake Malawi cichlids speciation
Lake Malawi cichlids speciation
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Polyploid speciation in plants
Polyploid speciation in plants
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Allopolyploid
Allopolyploid
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Hybrid sterility
Hybrid sterility
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Large X-effect
Large X-effect
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Drosophila hybridization
Drosophila hybridization
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Introgression in Drosophila mauritiana
Introgression in Drosophila mauritiana
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Hybrid Speciation in Finches
Hybrid Speciation in Finches
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Hybrid Origin of Sunflowers
Hybrid Origin of Sunflowers
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Introgression
Introgression
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Selection and Gene Flow
Selection and Gene Flow
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Hybrid Zones
Hybrid Zones
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Species Incompatibility Factors
Species Incompatibility Factors
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Favored Allele and Hybridization
Favored Allele and Hybridization
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Speciation with Gene Flow
Speciation with Gene Flow
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Study Notes
Lecture 15 Objectives
- Genetics of speciation
- Dobzhansky-Muller incompatibilities
- Speciation as an incidental effect of adaptation
- Reinforcement
- Sympatric speciation and leaky species boundaries
Dobzhansky-Muller Model of Species Incompatibility
- Problem with single-locus models
- Ancestral population splits followed by allopatric divergence
- Different alleles fix
- Hybrids may be sterile or inviable
- Incompatibility arises from the interaction of alleles at different loci.
Additional Concepts
- Observations from natural populations support the idea that isolation may be an incidental effect of directional selection
- Variation in mating systems and the intensity of selection can affect speciation rates.
- Ecological divergence is correlated with reproductive isolation.
- Reinforcement - selection acts directly to increase isolation
- Factors against reinforcement include gene flow into hybrid zones, deleterious pleiotropic effects of alleles increasing assortative mating, and weak genetic association.
- Empirical examples of reinforcement
- Sympatric speciation- in-situ evolution of reproductive isolation
- High speciation rates in taxa exhibiting bioluminescent courtship (or displays)
- Speciation associated with hybridization or gene flow
- Haldane's Rule- the sex with the heterogametic sex is more likely to have a hybrid inviability or sterility.
- X-chromosome may play a role for incompatibility
- Time for speciation may vary across groups.
- Polyploid speciation in plants
- Nest parasites are a good example of sympatric isolation
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