Decoding genetic information

What are mutations:

• Changes in WHAT sequence (DNA and RNA)

• Can be WHAT (WHAT) or not WHAT (WHAT)

• Changes can be small (WHAT level) or large (WHAT)

• Altered gene sequence can change the WHAT sequence of the polypeptide resulting in WHAT in the phenotypes

What are mutations:

• Changes in NUCLEIC ACID sequence (DNA and RNA)

• Can be INHERITED (GERMLINE) or not INHERITED (SOMATIC)

• Changes can be small (GENE level) or large (CHROMOSOMAL)

• Altered gene sequence can change the AMINO ACID sequence of the polypeptide resulting in VARIATION in the phenotypes

Effect on phenotypes can be

• WHAT = WHAT

• WHAT = WHAT 

• WHAT = WHAT 

Effect on phenotypes can be

• Harmless = neutral

• Harmful = Deleterious 

• Beneficial = Advantageous  

• Spontaneous mutations are naturally-occurring mutations mainly caused by WHAT errors (1 mutation/1010 bp of DNA replicated) and spontaneous WHAT

• Include WHAT removed A/G bases and WHAT (losing a group (cytosine to uracil))

• Spontaneous mutations are naturally-occurring mutations mainly caused by REPLICATIONS errors (1 mutation/1010 bp of DNA replicated) and spontaneous LESIONS

• Include DEPURINATION removed A/G bases and DEAMINATION (losing a group (cytosine to uracil))

Induced Mutations

• Natural (environment) or artificial agents (mutagens) that cause mutations at a rate much higher than WHAT mutations

• Induce mutations by replacing a WHAT, alter a base so it WHAT with another base, or WHAT a base where it can no longer pair with any base

• Base analogs: mimic WHAT and incorporates into DNA (can cause mispairing during DNA replication); e.g. 5-bromouracil:thymine analog that can pair with A or G

• Chemicals that alter base structure to cause WHAT (e.g. alkylating and intercalating agents-benzopyrene)

• WHAT to bases (UV light-thymine dimers, aflatoxin B-apurinic sites)

Induced Mutations

• Natural (environment) or artificial agents (mutagens) that cause mutations at a rate much higher than SPONTANEOUS mutations

• Induce mutations by replacing a BASE, alter a base so it MISPAIRS with another base, or DAMAGE a base where it can no longer pair with any base

• Base analogs: mimic BASES and incorporates into DNA (can cause mispairing during DNA replication); e.g. 5-bromouracil:thymine analog that can pair with A or G

• Chemicals that alter base structure to cause MISPAIRING (e.g. alkylating and intercalating agents-benzopyrene)

• DAMAGE to bases (UV light-thymine dimers, aflatoxin B-apurinic sites)

Germline mutation occur in WHAT, and therefore, are WHAT

Germline mutation occur in GAMETE FORMATION, and therefore, are HERITABLE

Example: sex-influenced trait – autosomal dominant trait
that is dependent on sex (males express the trait in
heterozygotes but females do not)

Somatic mutations:

• Somatic mutations occurs in a WHAT cell (any cell that first experiences the mutation) and all sequential WHAT cells express the mutation

• Somatic mutations are expressed as WHAT (size depends on time of mutation)

• Cancer tumors are an example of somatic mutations

Somatic mutations:

• Somatic mutations occurs in a PROGENITOR cell (any cell that first experiences the mutation) and all sequential DAUGHTER cells express the mutation

• Somatic mutations are expressed as SECTORS (size depends on time of mutation)

• Cancer tumors are an example of somatic mutations