Evolution Lecture 10: Quantitative Traits and Genetics - Darwin Day Celebration
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Questions and Answers

What is the term used to describe the interaction between alleles at different loci?

  • Epistasis (correct)
  • Recombination
  • Linkage equilibrium
  • Quantitative genetics

    • Which type of trait tends to vary continuously among individuals?

  • Mendelian traits
  • Monogenic traits
  • Binary traits
  • Polygenic traits (correct)

    • What generates genetic variation by mixing alleles?

  • Quantitative genetics
  • Polygenic traits
  • Recombination (correct)
  • Linkage equilibrium

    • In quantitative genetics, what is the term for the mixing and matching of alleles?

    <p>Linkage equilibrium</p> Signup and view all the answers

    Which type of traits have a complex genetic basis influenced by many genetic loci?

    <p>Polygenic traits</p> Signup and view all the answers

    What occurs if the occurrence of an allele at one locus is nonrandomly associated with another locus?

    <p>Linkage disequilibrium</p> Signup and view all the answers

    What does linkage disequilibrium in cats reflect?

    <p>Breed history</p> Signup and view all the answers

    Which method links traits with genes through the study of genomic regions?

    <p>Quantitative trait locus (QTL) analysis</p> Signup and view all the answers

    What is primarily identified by Genome-wide association studies (GWAS)?

    <p>Variants and genomic regions associated with particular traits</p> Signup and view all the answers

    What is often used in QTL analysis to identify genomic regions responsible for coat color in mice?

    <p>Single-nucleotide polymorphisms (SNPs)</p> Signup and view all the answers

    What is used to understand the link between phenotype and genotype?

    <p>Recombination</p> Signup and view all the answers

    What does the degree of linkage of different loci depend on?

    <p>Distance between them</p> Signup and view all the answers

    What does QTL analysis aim to link?

    <p>Traits with genes</p> Signup and view all the answers

    'Presence or absence of an allele at a second locus' is associated with which genetic concept?

    <p>Linkage disequilibrium</p> Signup and view all the answers

    What type of substitution in DNA sequences does not change the encoded protein?

    <p>Synonymous substitutions</p> Signup and view all the answers

    What indicates positive selection on DNA sequences when compared to synonymous sites?

    <p>Faster evolution</p> Signup and view all the answers

    What does a slower evolution than synonymous sites indicate on DNA sequences?

    <p>Purifying selection</p> Signup and view all the answers

    What is the dN/dS ratio also known as?

    <p>Ka/Ks ratio</p> Signup and view all the answers

    Which ratio would be expected for a gene under positive selection?

    <p>dN/dS &gt; 1</p> Signup and view all the answers

    What could lead to a dN/dS ratio of less than 1?

    <p>Purifying selection</p> Signup and view all the answers

    In the context of evolution rates, what could explain more similar dN/dS ratios between BRCA1 genes and immune genes?

    <p>&quot;Host-virus arms race&quot;</p> Signup and view all the answers

    What mechanism spreads adaptive alleles through a population more quickly than recombination acts to separate them from neighboring alleles?

    <p>&quot;Selective sweep&quot;</p> Signup and view all the answers

    What leaves a signature in neighboring alleles due to its rapid spread through a population?

    <p><strong>Selective sweep</strong></p> Signup and view all the answers

    What do gene trees depict?

    <p>Phylogeny of DNA sequence at a particular locus</p> Signup and view all the answers

    Which term is used to describe the common ancestry represented by nodes in gene trees?

    <p>Coalescence</p> Signup and view all the answers

    What can tracking phylogenies back in time lead to?

    <p>Population bottlenecks</p> Signup and view all the answers

    What may cause shallow coalescence in gene trees?

    <p>Positive selection</p> Signup and view all the answers

    Why may gene trees and species trees not always match?

    <p>Incomplete lineage sorting</p> Signup and view all the answers

    In gene trees vs. species trees, what does a gene tree depict specifically?

    <p>Evolutionary history of DNA sequences at a locus</p> Signup and view all the answers

    What does the dN/dS ratio measure in molecular evolution studies?

    <p>Rate of nonsynonymous mutations</p> Signup and view all the answers

    'Neutral theory' in molecular evolution suggests that most mutations are:

    <p>'Not subject to natural selection'</p> Signup and view all the answers

    'Selection' on DNA sequences usually affects which type of mutations?

    <p>'Nonsynonymous'</p> Signup and view all the answers

    'Rate of molecular evolution' refers to the speed at which:

    <p>'Mutations occur'</p> Signup and view all the answers

    What type of trait does the G ➔ T mutation represent in terms of nucleotides (bases)?

    <p>Synapomorphy</p> Signup and view all the answers

    What term describes the evolutionary relationships among different taxa?

    <p>Phylogeny</p> Signup and view all the answers

    What kind of genealogies do genetic loci have for their nucleotides (bases)?

    <p>Alleles</p> Signup and view all the answers

    In genetic terms, what are the Gs in Ts?

    <p>Alleles</p> Signup and view all the answers

    What is the term used to describe the mixing and matching of alleles?

    <p>Genetic recombination</p> Signup and view all the answers

    What does a synapomorphy indicate in terms of evolutionary relationships?

    <p>Common ancestor</p> Signup and view all the answers

    What happens when alleles at different loci are nonrandomly associated?

    <p>Linkage disequilibrium</p> Signup and view all the answers

    What type of genetic variation results from introgression?

    <p>Synapomorphy</p> Signup and view all the answers

    Which term describes the mixing of genetic material between different species or populations?

    <p>Gene flow</p> Signup and view all the answers

    What is the neutral theory of molecular evolution proposed by Motoo Kimura in 1968?

    <p>Most evolution at the molecular level is neutral and driven by genetic drift.</p> Signup and view all the answers

    What does synonymous (silent) mutation refer to in terms of DNA sequences?

    <p>It does not affect the amino acid sequence of the protein.</p> Signup and view all the answers

    What is the primary difference between synonymous and nonsynonymous mutations?

    <p>Nonsynonymous mutations are generally selectively neutral.</p> Signup and view all the answers

    What aspect of DNA evolution does the rate of molecular evolution refer to?

    <p>The variability in mutation rates among different DNA segments.</p> Signup and view all the answers

    In terms of DNA evolution, what is meant by '4-fold degenerate sites'?

    <p>DNA regions where mutations do not lead to amino acid changes due to redundancy in the genetic code.</p> Signup and view all the answers

    How does natural selection influence the fixation of mutations according to the neutral theory of molecular evolution?

    <p>Natural selection has no role in fixing mutations based on fitness advantages.</p> Signup and view all the answers

    What does the dN/dS ratio indicate when analyzing DNA sequences?

    <p>'dN/dS' is used to estimate the selective pressures acting on protein-coding genes.</p> Signup and view all the answers

    How do different types of DNA segments evolve according to the information provided?

    <p>'m', 'n', and 'c' segments evolve at different rates but consistently within organisms.</p> Signup and view all the answers

    'Neutral theory of molecular evolution postulates that ___.'

    <p>'most changes at the molecular level are due to genetic drift.'</p> Signup and view all the answers

    What term describes a homologous gene that arises due to gene duplication?

    <p>Paralog</p> Signup and view all the answers

    Which process involves the co-option of a particular gene for a totally different function as a result of a mutation?

    <p>Gene recruitment</p> Signup and view all the answers

    What led to the evolution of the ability to consume citrate in E. coli?

    <p>Gene duplication</p> Signup and view all the answers

    Which statement best describes paralogs?

    <p>Genes that arise from gene duplication</p> Signup and view all the answers

    What is the term for the process of reorganizing a preexisting regulatory network resulting in a major evolutionary event?

    <p>Gene recruitment</p> Signup and view all the answers

    Which event is an example of the evolution of a complex trait through gene duplication?

    <p>Consumption of citrate in E. coli</p> Signup and view all the answers

    What is the term for the recruitment of venom genes from genes expressed in multiple snake organs?

    <p>Gene recruitment</p> Signup and view all the answers

    What is the term used to describe similarity in traits or sequences due to inheritance from a common ancestor?

    <p>Homology</p> Signup and view all the answers

    Which genetic concept reflects the idea that flies and mice use homologous genes for dorsal-ventral patterning?

    <p>Homology</p> Signup and view all the answers

    What does the expression of HOXd13 in zebrafish and mouse embryos demonstrate about gene evolution?

    <p>Shared ancestry</p> Signup and view all the answers

    Why are flies and mice more likely to have homologous genes for dorsal-ventral patterning?

    <p>Shared ancient genetic toolkit</p> Signup and view all the answers

    What aspect of genetic networks often controls complex adaptations?

    <p>Regulatory networks</p> Signup and view all the answers

    Which of the following can have drastic effects on animal embryo development?

    <p>Mutations to genes at the top of the hierarchy</p> Signup and view all the answers

    What controls the shared ancestry of complex traits according to the text?

    <p>Genes, proteins, RNA, control regions, repressors, and transcription factors</p> Signup and view all the answers

    Which genetic concept experiences selection for a common, often novel, function?

    <p>Coexpressed traits</p> Signup and view all the answers

    What are complex adaptations controlled by?

    <p>Genes, proteins, RNA, control regions, repressors, and other transcription factors</p> Signup and view all the answers

    What is often involved in the development of animal embryos according to the text?

    <p>Hierarchical gene organization</p> Signup and view all the answers

    What is the focus of the lecture 'Quantitative Traits and Genetics'?

    <p>Genetic linkage</p> Signup and view all the answers

    Which concept refers to the occurrence of an allele at one locus being nonrandomly associated with the presence of an allele at another locus?

    <p>Linkage disequilibrium</p> Signup and view all the answers

    What does 'Polygenic trait' refer to in genetics?

    <p>Trait influenced by many genetic loci</p> Signup and view all the answers

    Which term describes the evolutionary relationships among different taxa?

    <p>Phylogenies</p> Signup and view all the answers

    What generates genetic variation by mixing alleles?

    <p>Recombination</p> Signup and view all the answers

    What type of traits tend to vary continuously among individuals?

    <p>Polygenic traits</p> Signup and view all the answers

    In quantitative genetics, what is the term for the mixing and matching of alleles?

    <p>Genetic linkage</p> Signup and view all the answers

    What does linkage disequilibrium in cats reflect, according to Alhaddad et al. 2013?

    <p>Individual genetic variations within a breed</p> Signup and view all the answers

    What does Quantitative Trait Locus (QTL) analysis aim to link?

    <p>Genomic regions responsible for specific traits</p> Signup and view all the answers

    What do Genome-wide association studies (GWAS) identify?

    <p>Variants and genomic regions associated with particular traits</p> Signup and view all the answers

    How is the relationship between phenotype and genotype understood in QTL analysis?

    <p>By linking genomic regions with specific loci</p> Signup and view all the answers

    What is the main focus of GWAS according to Palmer and Kronforst. 2020?

    <p>Identifying genes involved in mimicry in swallowtail butterflies</p> Signup and view all the answers

    How is linkage disequilibrium influenced in close loci on the same chromosome?

    <p>By the distance between loci</p> Signup and view all the answers

    Why are single-nucleotide polymorphisms (SNPs) often used in QTL analysis?

    <p>To identify genomic regions responsible for specific traits</p> Signup and view all the answers

    What can be inferred about loci close together on the same chromosome based on the degree of linkage?

    <p>They demonstrate a nonrandom association.</p> Signup and view all the answers

    What is a main requirement for natural selection to occur?

    <p>High heritability</p> Signup and view all the answers

    Which component of fitness refers to an individual's reproductive success?

    <p>Fecundity</p> Signup and view all the answers

    Which scientist contributed significantly to the understanding of natural selection but is not always credited with the discovery?

    <p>Alfred Russel Wallace</p> Signup and view all the answers

    What type of selection favors alleles that lower fitness?

    <p>Negative selection</p> Signup and view all the answers

    Which concept describes the contribution of individuals with one genotype compared to the fittest genotype in the population?

    <p>Relative fitness</p> Signup and view all the answers

    What do organisms need to possess for natural selection to occur?

    <p>High heritability</p> Signup and view all the answers

    Which scenario would violate Hardy-Weinberg equilibrium?

    <p>Natural selection</p> Signup and view all the answers

    'Fitness' in evolutionary terms is best described as:

    <p>'Survival and reproduction'</p> Signup and view all the answers

    What type of selective response is favored when intermediate size is selected for?

    <p>Stabilizing selection</p> Signup and view all the answers

    'Variation' in the context of natural selection refers to differences in:

    <p>'Genetic makeup'</p> Signup and view all the answers

    In the context of the text, what property reflects the genotype of an individual?

    <p>Gall diameter</p> Signup and view all the answers

    What type of selection leads to the evolution of similar ecomorphs like the multicolored tanager?

    <p>Directional selection</p> Signup and view all the answers

    What concept is used to describe the heritability of gall diameter in the text?

    <p>Genetic correlation</p> Signup and view all the answers

    What type of genetic change is favored when low-Eda alleles are present at low frequencies in marine environments?

    <p>Hardy-Weinberg equilibrium violation</p> Signup and view all the answers

    What does the rapid loss of armor in Loberg Lake indicate about evolution?

    <p>'Repeated evolution' of low-plate phenotype</p> Signup and view all the answers

    Which genetic concept involves the production of variable lateral plates in stickleback due to Eda signaling?

    <p>'Quantitative trait locus (QTL) analysis'</p> Signup and view all the answers

    What aspect of natural selection does the repeated evolution of Anole 'ecomorphs' illustrate?

    <p>'Directional selection'</p> Signup and view all the answers

    'Replicated changes as natural experiments' suggest which evolutionary outcome?

    <p>'Parallel evolution'</p> Signup and view all the answers

    'High-Eda' and 'Low-Eda' alleles affecting armor in sticklebacks are examples of what genetic phenomenon?

    <p>'Hardy-Weinberg equilibrium violation'</p> Signup and view all the answers

    How did severe drought affecting the availability of food lead to the evolution of larger-beaked birds?

    <p>Harder, woody seeds became the only available food, favoring larger-beaked birds.</p> Signup and view all the answers

    In the context of natural selection, what does 'directional selection' refer to?

    <p>Selection that favors individuals at one extreme of the phenotypic range.</p> Signup and view all the answers

    What factor can lead to rapid changes in a population according to the text?

    <p>Natural selection.</p> Signup and view all the answers

    How does coat color variation affect fitness in oldfield mice according to Hopi Hoekstra's research?

    <p>It affects the ability of mice to blend into their environment and avoid predators.</p> Signup and view all the answers

    What is implied by 'heritability' in the context of coat color variation affecting fitness in oldfield mice?

    <p>The ability of coat color to be passed down from one generation to the next.</p> Signup and view all the answers

    What phenomenon can lead to differences in fitness and survival among individuals in a population?

    <p>Natural selection.</p> Signup and view all the answers

    'Crypsis' in feather lice refers to:

    <p>'Cryptic coloration' that helps lice blend into their host's feathers.</p> Signup and view all the answers

    'Impaired preening ability' in painted lice studied by Bush et al. 2019 implies:

    <p>'Preening ability' is essential for lice survival and reproduction.</p> Signup and view all the answers

    'Experimentally induced evolution toward lighter coloration in pigeon lice' illustrates:

    <p>'Artificial' selection pressures leading to changes in lice coloration.</p> Signup and view all the answers

    What do experiments by Bush et al. 2019 on more conspicuous lice being removed by pigeons suggest?

    <p>Pigeons selectively remove more conspicuous lice, indicating a predator-prey interaction.</p> Signup and view all the answers

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