What is Kimura neutral theory and how is it relevant for phylogenetic study?
The neutral theory of molecular evolution by Kimura in 1968 states that most evolutionary changes at the molecular level are caused by random genetic drift of selectively neutral nucleotide substitutions. Due to the degeneracy of the genetic code, some point mutations are silent with no amino acid replacements.
Is gene flow a neutral process?
Nevertheless, neutral genetic markers have great potential for investigating processes such as gene flow, migration or dispersal. Hence, they allow us to empirically test the functional relevance of spatial indices such as connectivity used in landscape ecology.
Which 2 processes are most important in driving molecular evolution?
The evolution of living organisms is the consequence of two processes. First, evolution depends on the genetic variability generated by mutations, which continuously arise within populations. Second, it also relies on changes in the frequency of alleles within populations over time.
What are neutral variations?
Neutral Variation means that multiple alleles are present at a given genetic locus because those alleles are not distinguishable by natural selection.
What does selectively neutral mean?
A situation in which different alleles of a certain gene confer equal fitness.
When would we consider an allele to be selectively neutral?
Let us, for the moment, consider selectively neutral alleles, those that are not affected by natural selection, in a diploid population of N individuals (and therefore with 2N copies of the gene locus).
Which process is caused by natural selection?
Natural selection can lead to speciation, where one species gives rise to a new and distinctly different species. It is one of the processes that drives evolution and helps to explain the diversity of life on Earth.
Are most mutations neutral?
The majority of mutations are neutral in their effects on the organisms in which they occur. Beneficial mutations may become more common through natural selection. Harmful mutations may cause genetic disorders or cancer.
How does the nearly neutral theory modify the neutral theory of molecular evolution?
The emphasis of significance of weak selection in evolution distinguishes the nearly neutral theory from the neutral theory. The nearly neutral theory contends that the interplay of drift and weak selection is important and predicts that evolution is more rapid in small populations than in large populations.
How do neutral mutation affect evolution?
In population genetics, mutations in which natural selection does not affect the spread of the mutation in a species are termed neutral mutations. Neutral mutations that are inheritable and not linked to any genes under selection will either be lost or will replace all other alleles of the gene.
What is selectively neutral?
What are selectively neutral mutations?
A mutation whose fixation is independent of natural selection is termed a neutral mutation. Therefore selective neutrality of a mutation can be defined by independence of its fixation from natural selection.