Antimicrobial resistanceAntimicrobial resistance (AMR) occurs when microbes evolve mechanisms that protect them from the effects of antimicrobials (drugs used to treat infections). All classes of microbes can evolve resistance where the drugs are no longer effective. Fungi evolve antifungal resistance. Viruses evolve antiviral resistance. Protozoa evolve antiprotozoal resistance, and bacteria evolve antibiotic resistance. Together all of these come under the umbrella of antimicrobial resistance.
Mutation rateIn genetics, the mutation rate is the frequency of new mutations in a single gene or organism over time. Mutation rates are not constant and are not limited to a single type of mutation; there are many different types of mutations. Mutation rates are given for specific classes of mutations. Point mutations are a class of mutations which are changes to a single base. Missense and Nonsense mutations are two subtypes of point mutations.
Evolutionary arms raceIn evolutionary biology, an evolutionary arms race is an ongoing struggle between competing sets of co-evolving genes, phenotypic and behavioral traits that develop escalating adaptations and counter-adaptations against each other, resembling an arms race. These are often described as examples of positive feedback. The co-evolving gene sets may be in different species, as in an evolutionary arms race between a predator species and its prey (Vermeij, 1987), or a parasite and its host.
Viral quasispeciesA viral quasispecies is a population structure of viruses with a large number of variant genomes (related by mutations). Quasispecies result from high mutation rates as mutants arise continually and change in relative frequency as viral replication and selection proceeds. The theory predicts that a viral quasispecies at a low but evolutionarily neutral and highly connected (that is, flat) region in the fitness landscape will outcompete a quasispecies located at a higher but narrower fitness peak in which the surrounding mutants are unfit.
Adaptive mutationAdaptive mutation, also called directed mutation or directed mutagenesis is a controversial evolutionary theory. It posits that mutations, or genetic changes, are much less random and more purposeful than traditional evolution, implying that organisms can respond to environmental stresses by directing mutations to certain genes or areas of the genome. There have been a wide variety of experiments trying to support (or disprove) the idea of adaptive mutation, at least in microorganisms.
Experimental evolutionExperimental evolution is the use of laboratory experiments or controlled field manipulations to explore evolutionary dynamics. Evolution may be observed in the laboratory as individuals/populations adapt to new environmental conditions by natural selection. There are two different ways in which adaptation can arise in experimental evolution. One is via an individual organism gaining a novel beneficial mutation. The other is from allele frequency change in standing genetic variation already present in a population of organisms.
ParasitoidIn evolutionary ecology, a parasitoid is an organism that lives in close association with its host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionary strategies within parasitism, distinguished by the fatal prognosis for the host, which makes the strategy close to predation. Among parasitoids, strategies range from living inside the host (endoparasitism), allowing it to continue growing before emerging as an adult, to paralysing the host and living outside it (ectoparasitism).
Total fertility rateThe total fertility rate (TFR) of a population is the average number of children that would be born to a female over their lifetime if: they were to experience the exact current age-specific fertility rates (ASFRs) through their lifetime they were to live from birth until the end of their reproductive life. It is obtained by summing the single-year age-specific rates at a given time. , the total fertility rate varied widely across the world, from 0.78 in South Korea to 6.73 in Niger.
Interest rateAn interest rate is the amount of interest due per period, as a proportion of the amount lent, deposited, or borrowed (called the principal sum). The total interest on an amount lent or borrowed depends on the principal sum, the interest rate, the compounding frequency, and the length of time over which it is lent, deposited, or borrowed. The annual interest rate is the rate over a period of one year. Other interest rates apply over different periods, such as a month or a day, but they are usually annualized.
Site-specific recombinationSite-specific recombination, also known as conservative site-specific recombination, is a type of genetic recombination in which DNA strand exchange takes place between segments possessing at least a certain degree of sequence homology. Enzymes known as site-specific recombinases (SSRs) perform rearrangements of DNA segments by recognizing and binding to short, specific DNA sequences (sites), at which they cleave the DNA backbone, exchange the two DNA helices involved, and rejoin the DNA strands.
