Evo Lecture 5

Front

Genetic Variation : Where do mutations come from?

Back

-physical mutagens--> radiation (x-rays, UV)

-Chemical mutagens--> Base modifying agents, inter calculating agents, base analogs

• -Environmental mutagens--> drugs, cosmetics, food additives, pesticides, industrial compounds

• -errors in crossing over--> recombination causes structural rearrangement

Front

Mutations : Repair of DNA damage

Back

-prok and euk have repair mech deal with dna damage

-systems use enzymes to correct not 100% error free

-not all lesions are repaired and mutations happen at low freq

-cell death= high does of mutagens

Front

Induced Mutations

Back

- physical mutagens used to inc mutation freq to provide mutant organisms

-radiation (x-rays, uv radiation, radon) cause genetic damage by producing chem that effect dna causing unusual bonds between based

-radiation induced genetic damage not repaired mutation/ cell death = result

induce mutations for variability

Front

coding mutations

Back

- synonymous (codon changes but codes for same AA) (LYS--> LYS)

-non-synonymous (codon changes so does AA) (LYS-->HIS)

Front

Mutations Defined

Back

-Mutation is a change in DNA base pair or a chromosome

-Somatic mutations: only effects ind

-Germ line mutation: alter gametes (sperm/ eggs) effect next gen

Front

Mutations Quantified in 2 ways...

Back

1) mutation rate= function of time (number per gene per generation)

2) Mutation freq: number of times a mutation occurs in proportion to number of cells or ind. in a pop (X number per 100000 organisms)

Front

Human mutation rate

Back

-1*10^-8 mutations/ bp/gen

-60 mutations per person

-7.5 billion people in the world

Front

point mutations are divided into 2 classes based on phenotype...

Back

1) forward mutations- change genotype from wild to mutant

2) reverse mutations- change the genotype from mutant to wild type to partially wild type

Front

suppressor mutantion

Back

-cancel each other

-occurs at second site and completely or partially restores function that was lost or altered because of primary mutation

-first mustaion removed a function second mutation caused to regain function

Front

Intragenic vs Intergenic

Back

-Intra: within/ suppressor mutations within same gene where original mutation occured but at different site

-Inter: between/ suppressor mutations that occur in suppressor gene, gene is different that the one w/ original mutations