Lecture 14: DNA Mutations & Detection Methods Flashcards

Vocabulary flashcards based on the lecture notes about types of DNA mutations, detection methods, and related terminology.

Mutation

A change in a DNA sequence that is present in less than 1 percent of individuals in a population.

DNA Level Mutation

Results from substituting bases, or adding/deleting bases (aka POINT MUTATIONS).

Chromosome Level Mutation

When large sections of a chromosome are removed, added, or duplicated (aka CHROMOSOMAL ABNORMALITIES).

Germline Mutation

A mutation that occurs in gamete cells (eggs or sperm) and can be passed down to the next generation.

Somatic Mutation

A mutation that occurs in a somatic cell (adult differentiated cell) and cannot be passed down to the next generation.

Loss of Function DNA Mutation

Affects protein function and may lead to structural proteins or enzymes that no longer work—almost always inherited as recessive.

Gain of Function DNA Mutation

Leads to a protein with altered function (often due to a change in shape of the protein) -- almost always inherited as dominant.

Point Mutation

Changes a single base in the DNA sequence, resulting in a different codon in the mRNA sequence, leading to an incorrect amino acid being inserted into the protein sequence.

Silent Mutation

Changes DNA sequence, but has no effect on the resulting amino acids found in the protein—often found in noncoding regions of DNA.

Missense Mutation

Changes in the DNA sequence that leads to substitution of one amino acid for another in the final protein.

Nonsense Mutation

Involves a base substitution that causes a stop codon to form somewhere in the mRNA, resulting in a shortened, usually non-functional protein.

Loss of Stop Mutation

Involves a base substitution that destroys the original stop codon, resulting in translation continuing until another stop codon is encountered.

Frame-shift Mutation

Insertions or deletions of bases in DNA that interfere with translation and shift the “reading-frame,” producing nonfunctional proteins.

Induced Mutation

Mutations that are caused by exposure to a chemical agent (or radiation) that damages DNA, aka mutagens (External Sources of DNA damage).

Spontaneous Mutation

Mutations that are caused by naturally occurring errors in cellular processes (Internal Sources of DNA damage).

Single Nucleotide Polymorphisms (SNPs)

Inherited variations involving a single base—point mutations.

Short Tandem Repeats (STRs)

Short repetitive sequences occurring side by side on chromosomes, usually in noncoding regions.

Amniocentesis

Analyzing the chromosomes and biochemistry of the cells in the amniotic fluid for prenatal screening.

Allele-Specific Oligo-nucleotide Hybridization (ASOH)

A method that uses short synthetic DNA strands called oligo-nucleotide probes to bind to either the normal gene or mutant gene and produce a color change.

Restriction Fragment Length Polymorphism (RFLP)

Mutations in restriction sites that prevent normal enzyme cutting, seen as bands on an electrophoresis gel, unique to each individual.

Polymerase Chain Reaction (PCR)

Used to identify/copy specific sequences of DNA from an organism, whether to determine if a plant is transgenic or if a person carries a mutated gene.

cDNA Microarrays

Involves the preparation of two samples (control and experimental) for hybridization to the array, prepared from mRNA being extracted from cells and reverse transcribed into cDNA.