Lecture 4: Hardy-Weinberg Equilibrium Flashcards
Mechanisms of Evolution (Microevolution)
- mechanisms acting WITHIN populations, hence called “population genetics”
- Hardy Weinberg Principle (Mendelian Inheritance)
- Genetic Drift
- Mutation
- Sex: Recombination and Random Mating
- Natural Selection
Mechanisms of Evolution (Microevolution)
- Hardy Weinberg Principle (Mendelian Inheritance)
- Genetic Drift
- Mutation
- Sex: Recombination and Random Mating
- Epigenetic Inheritance
- Natural Selection
act on individuals in a Lamarckian manner
Epigenetic inheritance
Who is considered the “Father of Modern Genetics,” and what contribution did he make to our understanding of inheritance?
- Gregor Mendel
- He presented a mechanism for how traits are passed on, proposing the idea of particulate (genes) inheritance, where individuals pass alleles on to their offspring intact.
Mendel’s Laws of Inheritance
- only one allele passes from each parent on to an offspring
Law of Segregation
Mendel’s Laws of Inheritance
- different pairs of alleles are passed to offspring independently of each other
Law of Independent Assortment
Mendel’s Laws of Inheritance
- Law of Segregation
- Law of Independent Assortment
Using 29,000 pea plants, Mendel discovered the __ ratio of phenotypes, due to __
- 1:3
- dominant vs. recessive alleles
In cross-pollinating plants with either yellow or green peas, Mendel found that the __ always had yellow seeds (dominance). However, the __ consistently had a 3:1 ratio of yellow to green.
- first generation (f1)
- second generation (f2)
Mathematical description of Mendelian inheritance
Hardy-Weinberg Principle
Testing for Hardy-Weinberg equilibrium can be used to assess whether a population is __
evolving
A population that is not evolving shows allele and genotypic frequencies that are in __.
Hardy Weinberg equilibrium
Evolutionary Mechanisms (will put population out of HW Equilibrium):
Genetic Drift
Natural Selection
Mutation
Migration
change expression of alleles but not the frequency of alleles themselves, so they won’t affect the actual inheritance of alleles
*Epigenetic modifications
epigenetic modifications can change __, not __
- phenotype
- genotype
A population in Hardy-Weinberg Equilibrium serves as the __ (for no evolution) to test if evolution is happening.
Null Model
A region of genome sequence (DNA or RNA), that is the unit of inheritance , the product of which contributes to phenotype
gene
Location in a genome (used interchangeably with “gene,” if the location is at a gene… but, locus can be anywhere, so meaning is broader than gene)
locus
Variant forms of a gene (e.g. alleles for different eye colors, BRCA1 breast cancer allele, etc.)
allele
The combination of alleles at a locus (gene)
genotype
The expression of a trait, as a result of the
genotype and regulation of genes (green eyes, brown hair, body size, finger length, cystic fibrosis, etc.)
phenotype
We are diploid (__), so we have _ at a locus (any location in the genome)
- 2 chromosomes
- 2 alleles
If p and q represent the relative frequencies of the only two possible alleles in a population at a particular locus, then for a diploid organism (2 chromosomes)
(p + q)^2 = 1
= p2 + 2pq + q2 = 1
triploid organism
(p + q)^3 = 1
= p3 + 3p2q + 3pq2 + q3 = 1