So the mutation rate due to damage is affected by two factors: the relative impact of mutagens; and the efficiency of damage repair. Both of these factors can vary between species. Some mutagens arise internally due to cellular processes such as metabolism.
What factors affect mutation rate?
The size of the gene, its base composition, its position in the genome, and whether or not it is being actively transcribed influence its mutation rate.
What are two problems with molecular clocks?
While useful, molecular clocks are not fool-proof. Rates of change may not be constant, may not be the same in all organisms, and may be different for different genes.
Does generation time affect mutation rate?
Generation time and metabolism, each to some degree or in combination, affect the mutation rates of some organisms and, thus, their molecular evolutionary rates.
What causes mutation rates to increase?
Environmental exposures such as tobacco smoke, UV light, and aristolochic acid can result in increased mutation rates in cancer genomes. Mutation rates across individuals are also impacted by variability in the activity of certain cellular processes.
What increases mutation?
Mutations happen spontaneously. The rate of mutation can be increased by environmental factors such as UV radiation , X-rays, gamma rays and certain types of chemicals such as bromine.
What are the problems with the molecular clock?
The molecular clock runs into particular challenges at very short and very long timescales. At long timescales, the problem is saturation. When enough time has passed, many sites have undergone more than one change, but it is impossible to detect more than one.
What are some problems associated with molecular clocks?
Molecular clocks in general are much more “erratic” than previously thought, and practically useless to keep accurate evolutionary time, the researchers conclude. They attribute this to the vagaries of natural selection, which may at times constrain specific genetic mutations in certain lineages.
What is the specific potential problem with the use of the molecular clock?
In light of uncertainty in fossil dating and the rates of evolutionary change, the molecular clock cannot provide high levels of precision, but when used correctly it can still prove accurate: the lack of precision reasonably reflects our uncertainty about the past.
What affects generation time?
Generation time is one primary life-history trait that influences the molecular evolutionary rate. Theory predicts that organisms with shorter generation times evolve faster because of the accumulation of more DNA replication errors per unit time.
What determines the rate of evolution?
Discussion. The rate of evolution is typically deduced from three factors: mutation rate, population size and the fixation probability of new mutations.
What is the relationship between mutation rates and generation span?
What is the relationship between mutation rates and generation span? The mutation rates rise as the generation spans decrease.
What has the highest mutation rate?
The highest per base pair per generation mutation rates are found in viruses, which can have either RNA or DNA genomes. DNA viruses have mutation rates between 10−6 to 10−8 mutations per base per generation, and RNA viruses have mutation rates between 10−3 to 10−5 per base per generation.
How UV light can cause the mutation?
Ultraviolet (UV) light is a form of radiation that acts as a mutagen, an agent that causes mutations in DNA. Exposure to ultraviolet light causes chemical changes that alter the shape of your DNA, and the process that corrects DNA’s shape can also cause changes to the DNA code.