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Definition
| any heritable change in a gene. |
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Definition
| occurs in absence of a mutagen |
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Definition
| occurs in presence of a known mutagen |
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Definition
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Definition
| non-reproductive. Only in plants can somatic mutations be passed onto off spring via vegetative means. |
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Term
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Definition
Useful for genetic analysis. The reason is because they produce the phenotype in one set of environmental conditions (restrictive conditions) but not in another (permissive conditions.
An example of this is temperature sensitive mutations, where the phenotype of the mutation is only seen at a certain temperature. This is cause proteins fold differently at varying temperatures. |
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Term
Classification of mutations by function:
Loss-of-function
Hypomorphic
Hypermorphic
Gain-of-function |
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Definition
Loss-of-function: eliminates normal function and results in loss of gene product. Aka null mutations or "knockouts".
Hypomorphic: reduces gene expression, but does not eliminate it completely, 'leaky'.
Hypermorphic: produces greater than normal level of gene expression- gene product is overproduced.
Gain-of-function: expressed at wrong time or in incorrect location. A mutation that qualitatively alters the action of the gene.
Most loss of function mutation and hypomorphic mutations are recessive.
Many gain of function mutations are dominant. |
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Term
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Definition
| replace a pyrimidine base with another pyrimidine base. Or purine with purine. |
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Term
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Definition
| replacement of a pyrimidine to purine, or purine to pyrimidine. |
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Term
| Synonymous or silent mutations |
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Definition
those that change the nucleotide sequence without changing the amino acid sequence -> they change one codon into a ‘synonym’ for the same amino acid
Mutations outside of coding regions can be silent, i.e., have no detectable phenotypic effect -> the source of DNA polymorphisms
often in the 3rd position of a codon. |
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Term
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Definition
A nucleotide subsititution that results in a changed amino acid. Often occurs in the 1 or 2 position of the codon. Aka non-synonymous mutations.
ex: sickle-cell anemia. |
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Term
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Definition
| single base changed that results in a stop codon. Almost always makes the gene product non-functional. |
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Term
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Definition
shifts the reading frame of the codons in the mRNA; occurs if the length of the insertion or deletion is not a multiple of three! IF it is of 3 then it just adds or deletes amino acids completely from polypeptide chain.
ex: Fragile X |
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Term
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Definition
| Transposition is a cut and paste mechanism |
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Definition
| Transposition is a copy and paste mechanism using an RNA intermediate |
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Term
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Definition
| Repeat induced point mutation, a defense against transposons. |
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Term
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Definition
| the probability that a gene undergoes mutation in a single generation or in forming a single gamete. |
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Term
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Definition
| Certain areas of DNA more likely to undergo mutation than others. |
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Term
| deamination of cytosine and 5-methylcytosine. |
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Definition
When deamination occurs (loss of an amino acid from the polypeptide chain)on cytosine it is replaced with uracil. Uracil is recognized by the base excision repair system and is fixed.
Whden deamination occurs to 5-methylcytosine it is replaced with thymine. Thymine is a normal component of DNA and is thus not recognized by base excision repair, causing a mutation. |
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Term
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Definition
| is any agent that causes an increase in the rate of mutatino above the spontaneous background |
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Term
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Definition
| A or G lost from deoxyribose sugar |
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Term
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Definition
| an oxidizing agent is any chemical that readily transfers oxygen atoms |
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Term
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Definition
| : A base analog is a molecule similar enough to one of the bases that is can be incorporated into the DNA duplex in the course of normal replication |
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Term
| Chemical Agents That Modify DNA |
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Definition
| Ex, Alkylating agents, highly reactive chemicals that act as potent mutagens in both prokaryotes and eukaryotes |
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Term
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Definition
| Agents that act by inserting themselves between DNA base |
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Definition
UV light; chemical changes in the DNA bases as a result of absorption of the energy of light
Causes thymine dimer formation. |
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Term
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Definition
| Includes X-rays and the particles and radiation released by radioactive elements |
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Term
| Rate of spontaneous DNA damage in humans |
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Definition
| 1 x 10-9 per minute, 10,000 damaged sites per 24 hours. Most of it is repaired! |
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Term
| Human mitchondrial type of inheritance? |
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Definition
| It is maternally inherited. All progeny have the mother's mitchondrial genotype and phenotype. Thus females transmit all there mtDNA to all their offspring; whereas males transmit none! |
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Term
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Definition
| MHC= major histocompatibility complex, these genes play a central role in immunological self/nonself recognition |
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