Final Exam II Flashcards
(30 cards)
population genetics
studies the transmission between generation of genetic variation
population
a group of individuals of a single species living in the same time and place
the sum total of all alleles carried in all members of a population
gene pool
sample
a finite number of individuals used to make inferences about the population as a whole
allele
a variant at a specific locus, gene, region, or nucleotide position of the genome
The sample reveals only one allele at a nucleotide position
monomorphic
Polymorphic
if more than one allele or variant at a nucleotide site exists
genotype frequency
the proportion of total individuals in a population that carry a particular genotype
phenotype frequencies
two phenotypes in relative proportions to one another
proportion of gene copies in a population that are of a given allele type
allele frequency
Assumptions of the Hardy-Weinberg Law
-if certain assumptions were met, allele frequencies, genotype frequencies, and phenotype frequencies, would remain constant over time and between generations
1) the population is composed of a very large number of diploid individuals that, for all intents and purpose, is finite.
2) mating is random
3) no new mutations appear in the gene pool
4) no migration
5) different genotypes have no impact on fitness
fitness
the ability to survive to reproductive age and transmit genes to the new generation
Hardy-Weinberg Equilibrium (HWE)
allele and genotype frequencies for that locus will not change unless one of the assumptions is violated.
Monte Carlo simulation
a computer program that uses a random-number generator to choose an outcome for each probabilistic event
genetic drift
a change in allele frequencies as a consequence of the randomness of inheritance due to sampling error from one generation to the next
extinction
loss of an alleles from a population
fixation
a process whereby a single alleles of a locus becomes the only one in a population
founder effects
occurs when a few individuals separate from a larger population and establish a new one that is isolated from the original (migration of people to a new location)
population bottlenecks
occurs when a large population of individuals perish, often as a consequence of environmental disturbances or disease.
mutation
a variant DNA sequence in an individual’s genome that is not present in the genomes of either parent
deleterious mutations
disrupt important functions like the activity of an enzyme encoded by a gene
beneficial mutations
provide a relative selective advantage to an organisms or population which are relatively rare
neutral mutations
polymorphisms that provide little or no benefit no harm to the organisms
molecular clock
the ability to predict how long in the past different types of organisms diverged from a common ancestor by examining how different the DNA sequenced of these organisms are from each other
