Compensation mutations interaction of multiple

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compensation mutations-interaction of multiple alleles at different locihaploid bacteria—R- resistantr- sensitive (one locus)C- compensatedc- uncompensated (another locus)
-How do multiple genes interact to determine phenotypes?-compensation-What is Linkage Disequilibrium… arise? What is it? How does it change over evolution? How does it affect evolution?-Physical arrangement of genes influence evolutionary process?-What are Adaptive Landscapesand how do they help us understand the course of evolution?-How we can use quantitative genetic models to predict evolutionary change in traits even when we do not know the specific genetic basis for these traits?-breeders; how much variation due to heritable factors (additive, or odd interaction?)Polygenic Traits:-can exhibit nearly continuous variation-Mendelianinheritance explained aspects (discrete characters) of Darwin’s(NS of continuous traits) theory, but overall was a challenge for Darwin.--64 possible combinations if unlinked--- AaBbCc (AbC); continuous variation but gradientAABBCC:^^^^^v:^^^^vv:^^^vvv:^^vvvv:^vvvvv:vvvvvv1:6:15:20:15:6:1Additive genetic effects:allele effects on the phenotype sumnew phenotypes can arise from NOT mutation
Latent Variation:Re-assortment of existing variation (latent)Diploid population with 10 unlinked loci (A-J)... additive phenotype; no particular interaction2 alleles at each loci (A1 A2… etc.)Indivs have 20 allelesPhenotypes 0 (all A2B2C2…) 20 (all A1B1C1…)-if each allele frequency is 50% at each locus, unlikely for 0s or 20s; initially would be bell curve w max ~10 (no extremes)~With intense selection pressure or migration event…~ same but from 11-18 (other side of bell curve cut off); if THESE remaining indivs produce offspring:
disproportionate number of x1s, reducing x2 allele frequencies more likely to get to higher trait valuesEpistasis:alleles at 2+ loci interact in non-additive ways phenotype
Ex:coat color in mouse—2 loci (Mc1R & Agouti locus)Phenotypic effects are context dependent^Polygenics~~-some allele combinations increase in frequency, while others may be eliminated from population (due to interaction with other allele)Haplotype-a set of alleles, one from each locus under consideration (ex: ABc vs AbC… AABbCc =genotype)-To treat population genetics with multiple loci, need to track haplotype frequenciesEx:2 loci ∂ & ∫; each with two alleles A1A2 &B1B2Must keep track of not only how many A1 & A2 alleles (&Bs), but also of which alleles at the ∂ locus are associated with which alleles at the ∫ locus (haplotypes)AB- 33%Ab- 17%aB- 0%ab- 50%A- 50%a- 50%B-33%
b-67%
When loci and alleles independent of one anothers- freq AB t-Ab u-aB v-abFrequencies of haplotypes (gametes) expected to be directly associated with the frequencies ofthe different arrangements of alleles in the Hetero/Hetero parents.Linkage Disequilibrium-When statistical associations are present between the alleles at the A locus and at the B locusLinkage- loci linked on chromosome
Disequilibrium- phenotypic frequencies out of HWED-

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