4/10-4/24 Lecture Notes

📘 EvoDevo & Complexity Flashcards

Q: What are the two central problems of development in multicellular organisms?
A: (1) How does a single cell make an adult body? (2) How does an adult body make offspring?

Q: What is the genotype-phenotype map?
A: It's the process that maps genetic information (genotype) to the physical form (phenotype).

Q: Why is the evolution of phenotypes really the evolution of development?
A: Because phenotypes are produced through developmental processes.

Q: What is heterochrony?
A: Evolutionary change in the timing and rate of developmental events (e.g., neoteny).

Q: Define pleiotropy.
A: One gene affects multiple traits.

Q: Define epistasis.
A: When the effect of one gene is modified by one or more other genes.

Q: What is antagonistic pleiotropy?
A: A gene has multiple effects that may be beneficial for one function but harmful for another.

Q: How does gene duplication contribute to complexity?
A: It allows one gene copy to maintain function while the other diversifies or gains new functions.

Q: What are the three possible outcomes after gene duplication?
A: (1) Subfunctionalization, (2) Neofunctionalization, (3) Pseudogenization

Q: What is subfunctionalization?
A: Duplicate genes divide the original functions between them.

Q: What is neofunctionalization?
A: One gene copy acquires a new function.

Q: What is canalization?
A: The ability of a genotype to produce the same phenotype regardless of environmental variability.

Q: What is modularity in development?
A: Traits grouped into semi-independent modules, allowing easier evolutionary changes.

Q: What role do Hox genes play in development?
A: They control anterior-posterior body patterning and segment identity.

🌱 ETIs – Major Transitions in Evolutionary Individuality Flashcards

Q: What is an evolutionary transition in individuality (ETI)?
A: A transition from a group of cooperating individuals into a new, higher-level evolutionary individual.

Q: Give three examples of major ETIs.
A: (1) RNA replicators to protocell, (2) Prokaryotes to eukaryotic cells, (3) Cells to multicellular organisms.

Q: What is fitness decoupling?
A: Group-level fitness becomes independent of the average fitness of lower-level units.

Q: What are key criteria for individuality?
A: Indivisibility, genetic homogeneity, spatial/temporal boundaries, physiological integration, and division of labor.

Q: What’s the role of germ-soma differentiation in ETIs?
A: It enables division of labor and specialization in reproduction vs. somatic maintenance.

Q: What is the volvocine algae clade used to study?
A: Gradual evolution of multicellular individuality (e.g., Gonium to Volvox).

Q: What is meant by 'reorganization of fitness'?
A: Fitness shifts from individuals to the group level as specialization evolves.

Q: What mechanisms support ETIs?
A: Cooperation, conflict mediation, co-option of life-history genes, and specialization.

Q: What’s an example of a species with partial individuality?
A: Gonium—cells can survive alone and group fitness equals average cell fitness.

Q: What is the significance of Volvox in ETI studies?
A: It exhibits complete fitness decoupling and full germ-soma differentiation.

Q: What is the hierarchical structure of life?
A: Nested levels of organization: genes → cells → multicellular organisms → social groups.

🧬 Evolution of Sex Flashcards

Q: What is the paradox of sex?
A: Despite high costs, sex is common. Why? What are its evolutionary benefits?

Q: List three major costs of sexual reproduction.
A: (1) 2-fold cost of males, (2) Breaks apart beneficial gene combinations, (3) Energy for mating.

Q: What is recombination?
A: The process of mixing genetic material through crossing-over or DNA exchange.

Q: What is linkage disequilibrium (LD)?
A: Non-random association of alleles at different loci.

Q: Why does sex matter more when LD ≠ 0?
A: Because recombination can reshuffle alleles more effectively under LD.

Q: What is Muller’s Ratchet?
A: Asexual populations accumulate deleterious mutations over time.

Q: What is the Fisher-Muller hypothesis?
A: Sex accelerates adaptation by combining beneficial mutations.

Q: What is the Red Queen hypothesis?
A: Sex allows hosts to keep up in evolutionary arms races with parasites.

Q: How did meiosis evolve?
A: Through gene duplication of prokaryotic DNA repair genes (e.g., RecA → Rad51, Dmc1).

Q: What is amphimixis?
A: Sexual reproduction involving meiosis and fusion of gametes from two parents.

Q: How does sex relate to DNA repair?
A: Meiotic recombination evolved to repair double-strand DNA damage.

Q: What is the DSBR model?
A: The double-strand break repair model of meiotic recombination.

Q: What is the origin of meiosis genes like Spo11 and Dmc1?
A: They evolved by duplication from DNA repair genes in prokaryotes.

Q: What is the "immortality of life" concept in this context?
A: Sex preserves the continuity and integrity of life by preventing the accumulation of mutations.

Question: in a population at the coupling disequilibrium

a LD is negative

b LD is positive

c LD is zero

d Selection is effective

e Selection is stalled

f Good alleles associated with bad

g Recombination increases fitness variance

Answer- B&D

Question: in a population at the repulsion disequilibrium

a LD is negative

b LD is positive

c LD is zero

d Selection is effective

e Selection is stalled

f Good alleles associated with bad

g Recombination increases fitness variance

Answer- A, E, F, G