Evolutionary biology 9-11

Know the basic differences between Mendelian traits and quantitative traits

traits inherited as dominant and recessive,Each genotype has one phenotype. While quantitative traits are polygenic and are affected by the environment.Each phenotype is determined by many genes.

-Population vs quantitative genetics:

Population examines discrete genotype. Alleles and genotype frequencies of populations. Qualitative examines continuously distributed phenotypes. Mean and variance of populations.

-Know the distributions of quantitative traits

 Quantitative traits often occur in a normal distribution

Know the difference between dominance, additive and epistatic traits

-Dominance

 one allele masks another

-Additive

Allele combine to create ex: each allele adds height, A adds 2 cm a adds 3 cm

-Epistatic:

Separate loci interact to create a phenotype Ex: If gene A makes pigment and Gene B determined the pigment color if Gene A doesn't make pigment then Gene B doesn’t matter.

-Why study quantitative traits:

 Useful to measure how much variation is genetic, differences in fitness, and predict evolutionary responses to selection

-What are QTLs?:

 QTL are a statistical creation that identifies a particular region of the genome as containing a gene associated with trait of interest.

-How does QTL mapping works:

 Quantitative Mapping locates gene that have effects on quantitative trait using a linkage map. If a significant association is found between trait and neutral markers that means QTL is near.

-LOD score

Log-odds ratio, measures how likely a QTL is attached to a neutral marker. High peak(LOD)= most likely a QTL

-Know how to measure heritable variation in quantitative traits:

 P= G+E

 P = Phenotype

G = Genetic variation

E = Environmental variation

-Understand selection differentials:

 Selected mean is the average trait value of individuals that reproduce while original mean is the average trait value of the whole population

-Understand how to calculate response to selection in quantitative traits:

R=h2S . Predicts how much the next generation will change bc of selection

Know the types of selection on trait distributions:

Direction (one extreme), stabilizing (intermediate), disruptive (both extremes)

 Giraffe’s neck case study

. Fly wing markings case study

Know the role of observational studies in studying adaptation

Garter snake case study

Know the comparative method and how it is used

Bat testes case study

Felsenstein’s method

Know what evolutionary tradeoffs are and how they work

Fuchsia excoricata case study

Know sexual dimorphism and what causes it

Purple-throated caribs case study

Know differences between male and female fitness variance and other asymmetries in sexual reproduction

Fruit fly case study

Intrasexual selection

Male-Male Competition

Marine iguana case study

Alternative mating strategies

Coho salmon case study

Sperm Competition

Infantacide

Lion case study

Intersexual selection

Reasons for female choosiness

Barn Swallow case study

Tree Frog case study

Hangingfly case study

Water mite case study

Runaway Selection

Stalk-eyed flies

Diversity in sex roles

. Pipefish case study

Flower case study

Clownfish Case study

Anglerfish cases study

Flatworms case study

Sex ratio

Fisher’s principle

Operational sex ratio

Human sexual dimorphism

Handicap hypothesis