Genetics and Evolution Flashcards
Alleles
Alternative forms of a gene. Dominant allele only
requires 1 copy in order to be expressed. Recessive
allele requires two copies in order to be expressed.
P + q = 1
P^2 +2Pq + q^2 = 1
Genotype:
The combination of alleles one has at a given locus.
Homozygous: Having two of the same allele.
Heterozygous: Having two different alleles.
Penetrance:
The proportion of individuals carrying a particular
allele that also express an associated phenotype.
Expressivity:
The varying phenotypic outcomes of a genotype
Genetic Leakage
: Flow of genes between species via hybrid offspring
Genetic Drift:
When the composition of the gene pool changes as a
result of chance.
Founder Effect:
Bottlenecks that suddenly isolate a small population;
inbreeding.
Taxonomic
Kingdom, phylum, class, order, family, genus, species.
“King Phillip Came Over From Great Spain”
Law of Segregation
: An organism has two alleles for each gene, which
segregate during Anaphase I. Because of this,
gametes carry only one allele for a trait.
Law of Independent
Assortment
The inheritance of one allele does not influence the
probability of inheriting a given allele for a different
trait (except for linked genes).
Griffith:
Demonstrated transformation. Heat-killed smooth
(virulent) strain of bacteria still transformed rough strain
into smooth.
Avery-MacLeod-McCarty
Degradation of DNA led to a cessation of bacterial
transformation. Degradation of proteins did not
Hershey-Chase:
Confirmed DNA is the genetic material because only
radiolabeled DNA could be found in bacteriophage-infected bacteria
Point Mutations:
The substituting of one nucleotide for another.
Frameshift Mutations:
Moving the 3 letter reading frame.
Recombination
Frequency:
The likelihood of two alleles being separated during
crossing over in meiosis.
Hardy-Weinberg
Principle:
If a population meets certain criteria (aimed at a lack
of evolution), then the allele frequencies will remain
constant
Hardy-Weinberg
Equation:
P + q = 1
p^2 + 2Pq + q^2 = 1
Modern Synthesis Model
Neo-Darwinism. Mutation and recombination are mechanisms of variation. Differential reproduction
Inclusive Fitness
If a population meets certain criteria (aimed at a lack of evolution), then the allele frequencies will remain constant.
Punctuated Equilibrium
Considers evolution to be a very slow process with intermittent rapid bursts of evolutionary activity.
Mode of Natural Selection:
Stabilizing selection
Directional selection
Disruptive selection
Adaptive radiation
Stabilizing Selection:
: Keeps phenotypes in a narrow range, excluding extremes.
Directional Selection:
Moves the average phenotype toward an extreme.
Disruptive Selection:
Moves toward two different phenotypes at the extremes, can lead to speciation
Adaptive Radiation
Rapid emergence of multiple species from a common ancestor, each has a niche.
Molecular Clock Model:
The degree of difference in the genome between two species is related to the amount of time since the two species broke off from a common ancestor.