Experimental Evolution
These organisms are often used in evolutionary experiments because of their ability to rapidly reproduce.
Microbes
This evolutionary force favors organisms with traits better suited for survival.
Natural selection
In this process primarily present in asexual populations, beneficial mutations compete with each other.
Clonal interference
These specific phenotypic changes were seen in the LTEE.
Increased biofilm production, higher metabolic capacity, cell size gains, thermal tolerance
This process involves transferring a small fraction of a microbial population into fresh medium each day
Serial transfer
The Long-Term Evolutionary Experiment (LTEE) uses this species of bacteria.
E. coli
This coefficient measures the fitness of a certain mutation in a population.
Selection coefficient (s)
These DNA changes create genetic variation and can be beneficial, harmful, or neutral
mutations
This evolutionary pattern occurs when the same mutation appears independently in multiple populations
parallel evolution
These population reductions occur during daily transfers and increase the effects of genetic drift
population bottlenecks
Evolutionary experiments often start with this type of strain so that the starting genetics of the organism are known.
Ancestral strain
When the product of effective population size and selection coefficient is much greater than one, this evolutionary force dominates over genetic drift
Natural Selection
In rapidly growing microbial populations, this biological process is responsible for generating most new mutations
DNA replication
This is common in asexual populations where beneficial mutations compete against each other because recombination cannot combine them
clonal interference
This technology allows researchers to identify mutations in evolved populations.
genome sequencing
This type of media is used to transfer and grow E. coli in the LTEE.
Glucose minimal media
This term describes the process where a mutation reaches a frequency high enough to escape loss by genetic drift.
mutation establishment
This type of mutation improves an organism’s fitness and is likely to increase in frequency through natural selection
Beneficial Mutation
In the LTEE, some evolved E. coli developed this structural lifestyle that increases surface attachment and community growth
biofilm formation
This famous experiment started in 1988 and continues today with E. coli populations evolving for tens of thousands of generations
Long-Term Evolution Experiment
This method combines evolution experiments with genome sequencing to identify adaptive mutations in populations
evolve-and-resequence
This variable represents the effective number of individuals contributing genes to the next generation.
effective population size (Ne)
Because bacteria divide rapidly, experimental populations can generate thousands of new mutations during this time period
a single generation
When a mutation spreads through a population until every individual carries it, this evolutionary outcome has occurred
fixation
This bacterial species is used in the LTEE because it grows quickly and is easy to culture in the lab.
Escherichia coli