Lesson 4: Hardy Weinberg Equilibrium Flashcards
Darwin’s observation
- evolution acts through CHANGES IN ALLELE FREQUENCE at each generation
- leads to average change in characteristic of population
“individuals pass allels on to their offspring intact”
idea of particulate (genes) inheritance
Mendel’s Laws of Inheritance
- Laws of Segregation
- Law of Independent Assortment
only one allele passes from each parent on to an offspring
Law of Segregation
different pairs of alleles are passed to offspring independently of each other
Law of Independent Assortment
what did Mendel discover using 29,000 pea plants
1:3 ratio of phenotypes due to dominant vs. recessive alleles
mathematical description of Mendelian inheritance
Hardy-Weinberg Principle
what is the testing for Hardy-Weinberg equilibrium can be used to
asses whether a population is evolving
genotypic frequencies that are in Hardy-Weinberg equilibrium
population that is not evolving
genotypic frequencies not in Hardy-Weinberg equilibrium
population is evolving
Evolutionary Mechanisms that will put population out of HW Equilibrium
- genetic drift
- natural selection
- mutation
- migration
genetic drift
- change in frequency of an existing gene variant in the population due to RANDOM chance
- may cause gene variants to disappear completely and thereby reduce genetic variation
natural selection
idea that organisms that are best suited to survive pass their traits down
mutation
change in the DNA sequence of an organism
migration
causes the transfer of genes from one population to the othe
change expression of alleles but not the frequency of alleles themselves, so they won’t affect the actual inheritance of alleles
epigenetic modifications
an evolving population is one that __ Hardy-Weinberg Assumptions
violates
Requirement of HW -> Evolution
large population size -> ?
genetic drift
Requirement of HW -> Evolution
random mating -> ?
inbreeding & other
Requirement of HW -> Evolution
no mutations -> ?
mutations
Requirement of HW -> Evolution
no natural selection -> ?
natural selection
Requirement of HW -> Evolution
no migration -> ?
migration
group of individuals of the same species interacting within the same space
population
according to the Hardy-Weinberg principle, frequencies of alleles and genotypes in a population remain __ from generation to generation
constant
the genotype frequencies you see in a population should be the ___ __, given the allele frequences
Hardy-Weinberg expectations
a population in Hardy-Weinberg Equilibrium sevse as the __ __ to test if evolution is happening
null model (for no evolution)
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 or gene
locus
plural of locus
loci
variants forms of a gene
allele
combinationof alleles at a locus
genotype
the expression of a trait, as a result of the genotype and regulation of genes
phenotype
2 chromosomes
diploid
Hardy-Weinberg Equlibrium formulas
- p+q = 1
- p^2 + 2pq + q^2 = 1
- (p+q)^3 = 1
- p^3 + 3p^2q + 3pq^2 + q^3 = 1
- metabolic disorder that results from homozygosity for a recessive allele
- cannot break down phenylalanine
phenylketonuria (PKU)
five conditions for nonevolving populations are met in nature
- no mutations
- random mating
- no natural selection
- extremely large population size
- no gene flow
can be used to determine if a population is significantly different from the expectations of Hardy-Weinberg model
X^2 goodness-of-fit test
statistical test used to examine the differences between categorical variables from a random sample in order to judge the goodness of fit between expected and observed results.
Chi-square
X^2 = ?
E ((O-E)^2/E)
a nonevolving population is in __ __
HW Equilibrium
occurs when the requirement for HW Equilibrium are not met
evolution
HW Equilibrium is violated when there is …
- genetic drift
- migration
- mutations
- natural selection
- nonrandom mating
p- value = ?
0.05
degree of freedom (df) - ?
of classes - # of frequencies - 1
No. of classes
genotype (3)
No. of frequencies
allele (1)
X^2 tab,0.05,1 = ?
3.8415
tendency for people to choose mates who are more similar (positive) or dissimilar (negative) to themselves in phenotype characteristics than would be expected by chance.
Assortative mating
