ANTH- Test 1 (4)

Change in allele frequencies in a population/ species over time

1. The only way of introducing new genes & new alleles of a gene into a species

2. Most mutations are harmful or "neutral", through the natural selection advantage or disadvantage is contingent on the environment conditions in which the mutation is expressed phenotypically 

3. Persistence and spread of a mutation within a population/ species are by natural selection

4. Mutations are random events. For a mutation to be important in evolution, it has to occur in a sex cell

• 1. Point mutation
• 2. Chromosomal rearrangement 
• 3. Imbalance in chromosome number

Change in a single nucleotide (due to error in replication)

1. No change in amino acid sequence of the protein; no change in the protein

2. Change in amino acid sequence of the protein; change is not functionally important ("neutral" mutation")

genes and alleles

The position of a gene on a chromosome may be important in its expression. Therefore, if the position of a gene is changed, its phenotypic expression may also be changed

• There are different scales of mutation
• From change of one nucleotide to am imbalance in chromosome number. The larger the scale of mutation, more likely the greater the phenotype effect

Mutations may/ may not have phenotypic consequences

• 1. Phenotypic frequency distributions 
• 2. Formula for calculating # of genotypes for a polygenic trait 
• 3. Heritability

, (G is raised to the power)

• a= # of alleles of a gene
• G= # of genes being considered

Proportion of phenotypic variation associated w/ genetic variation

Heritability = genotype/ phenotype