Small Scale Mutations
When an mutation occurs but the codon still codes for the same amino acid and result in a fully functional protein.
synonymous or silent mutation
The process of creating new genes from duplicates of old ones
duplication and divergence
Mutations are typically spontaneous and are caused by
mutagens
Focuses on interactions between females and males.
Intersexual selection
The random change in allele frequencies from generation to generation, meaning that frequencies can go up or down simply by chance
genetic drift
When the amino acid sequence is changed due to the mutation, the protein may fold in correctly, causing it to no longer function.
nonsynonymous or missense mutation
Joining of segments from nonhomologous chromosomes.
Reciprocal translocation
1. Mut s recognizes mismatched bases in DNA and initiates the repair process
2. Mut L and Mut H proteins are recruited, and Mut H breaks the backbone some distance away
3. An exonuclease removes nucleotides, including the one with the mismatched base
4. DNA polymerase fills in the missing nucleotides, and a DNA ligase brings together the backbones
Mismatch repair
Heterozygous genotype has a higher relative fitness than either the homozygous dominant or homozygous recessive genotype. Sickle Cell gene is an example of this.
Heterozygous advantage
When an initially large and diverse population is subject to a major reduction in number, typically due to some natural disaster. Only a subset of individuals survive this disaster, so only a subset of the initial genetic diversity is present. The population eventually recovers, but the drift acting on the small populations causes diversity to decrease further.
Population Bottleneck
cystic fibrosis is an example of what type of mutation
deletion
Multiple rounds of duplication and divergence can give rise to a group of genes with related functions
gene family
1. One or more damaged bases signal the repair process
2. Enzymes cleave the DNA backbone at sites of damage
3. The region with damaged bases is removed
4. The gap is filled by new DNA synthesis, using the ungapped strand as the template
Nucleotide excision repair
Acts against intermediate traits ( berries and apples example)
Disruptive selection
When a subset of a large and diverse population leaves the original habitat and colonizes a new habitat.
Founder Effect
why do mutations in noncoding DNA have no detectable effects on the organism.
In a noncoding region, the DNA has no known function.
When the normal order of a block of genes is reversed
inversion
1. A nucleotide base, such as Uracil, signals the repair process
2. A specialized enzyme, such as DNA uracil glycosylase, removes the base from the deoxyribose sugar
3. AP endonuclease removes the backbone and removes the sugar
4. Other enzymes close the gap by new DNA synthesis, using the intact nucleotide opposite the site as a template
Base excision repair
Shifts the population mean
Directional selection
The correlation between the time two species have been evolutionarily separated and the amount of genetic divergence between them
Molecular clock
What enzyme is responsible for proof reading?
DNA polymerase
DNA sequences that can move from one position to another in the genome. They can insert into a gene and disrupt its function.
Transposable elements or transposons
X-rays
Uv light
Tobacco
chemicals such as bleach and hydrogen peroxide
Examples of mutagens
Successful genotypes are selected by the breeder, not through competition
Artificial selection
The changes and variations in genetic code that occur over time
Molecular evolution