BIOL 207 Lecture 5 - Mutations, Alleles, and Aberrations (Terms)

Point Mutation

Alteration of a single base pair in a DNA strand to cause a mutation

Substitution Mutation

A type of point mutation where a single nucleotide base pair is replaced with another

Insertion/Deletion Mutation (INDEL)

A type of point mutation in which a single nucleotide is either added or deleted

Transition Mutation

A type of substitution mutation that replaces a nucleotide with the same type of base nucleotide, such as a purine to a different purine or a pyrimidine to a different pyrimidine

Transverse Mutation

A type of substitution mutation that replaces a nucleotide with a different type of base nucleotide, such as a purine to a pyrimidine or a pyrimidine to a purine

Spontaneous Replication Errors

An error in the nucleotide strand that arises during replication, leading to a mutation

Depurination

The loss of an entire purine from a nucleotide, resulting in a gap in a nucleic acid strand

Deamination

The loss of an entire amino group (NH2) from a base nucleotide, changing the structure of the nucleotide base to a different one

Base Excision Repair (BER)

A DNA repair system capable of repairing gaps created by depurination as well as able to recognize some spontaneous conversions (T → U deamination)

Nucleotide Excision Repair

A DNA repair system capable of repairing UV induced distortions in the DNA strand such as pyrimidine dimers

Mismatch Repair

A DNA repair system capable of repairing incorrectly incorporated nucleotides after proofreading polymerase activity

Synonymous Mutation

A classification of point mutation that affects a codon in a position that does not alter the encoded amino acid

Silent Mutation

A general term for a mutation that has no effect on the function and sequence of the encoded protein, regardless which part of the gene is hit

Missense Mutation

A classification of point mutation that affects a codon so that a different amino acid is incorporated

Nonsense Mutation

A classification of point mutation that changes a protein codon into a stop codon, causing premature termination of the protein

Frameshift Mutation

A classification of point mutation caused by INDEL mutations that alters the reading frame of codons, changing all subsequent codons

Cystic Fibrosis

A condition affecting the lung mucus membranes caused by a point mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene that affects either protein coding regions or RNA processing regions on the gene

Preaxial Polydactyly

A condition causing abnormal number of digits on a limb, caused by mutation in the regulatory region of the gene important in limb development

Single Nucleotide Polymorphism (SNP)

Single nucleotide variations in the human genome, which originated from point mutations and became “fixed” in the population

Somatic Mutation

A mutation that occurs in a body cell of a mature/differentiated organism that has been fertilized

Germline Mutation

A mutation that occurs in the reproductive gametes of an organism

Genetic Mosaic

An organism’s tissue that contains genotypically different regions, typically as a result of a somatic mutation

Chromosome Mutation

Changes in a region of DNA that harbours multiple genes

Gene Mutation

A mutation that affects a single gene’s function

Translocation

A chromosome mutation involving the relocation of a large chunk of DNA from one chromosome to another, changing the information content of the wild type gene

Inversion

A chromosome mutation involving the swapping of two gene sequences in a chromosome

Deletion

A chromosome mutation involving the loss of a large sequence of DNA from a chromosome

Duplication

A chromosome mutation involving the duplication of a large sequence of DNA in a gene