Genetic Mutations and Epigenetics

Vocabulary flashcards covering point mutations, frameshift mutations, chromosomal alterations, associated genetic diseases, mutagens, and epigenetics from lecture notes.

Substitution Mutation

A mutation in which a single DNA base is swapped for another, which may change an amino acid in the synthesized protein.

Missense Mutation

A point mutation where a single DNA base swap results in the DNA coding for the wrong amino acid in the protein, which can affect structure and function.

Nonsense Mutation

A point mutation where a single DNA base change prematurely creates a stop codon, halting protein production early and resulting in a truncated protein.

Silent Mutation

A point mutation where a DNA base changes, but the resulting amino acid remains the same due to the redundancy of the genetic code, typically causing no disease.

Frameshift Mutation

An insertion or deletion of nucleotides in numbers not divisible by three, which shifts the downstream reading frame and damages protein coding.

Repeating Mutation (Trinucleotide Repeat)

A mutation where a short sequence of bases (often triplets) is abnormally repeated too many times.

Chromosomal Deletion

A structural mutation where a large segment of a chromosome breaks off and is lost.

Chromosomal Translocation

A chromosomal alteration where a piece of one chromosome breaks off and attaches to a completely different chromosome.

Sickle Cell Anemia

A condition caused by a missense point mutation that alters red blood cell shape, causes vaso-occlusion, and confers resistance to malaria in trait carriers.

Huntington's Disease

A genetic disorder associated with an abnormal repeat mutation featuring expanded $CAG$ trinucleotide repeats in the HTT gene.

Cri-du-Chat Syndrome

A genetic disorder caused by a large chromosomal deletion on chromosome 5.

Chronic Myelogenous Leukemia (CML)

A cancer caused by a chromosomal translocation involving the Philadelphia chromosome, $t(9;22)$.

Splice Site Variant

A change in the DNA sequence that alters normal RNA splicing, potentially causing a seemingly silent mutation to have drastic effects on the final protein.

Spontaneous Mutation

A naturally occurring genetic mistake that arises without environmental damage, typically when DNA polymerase makes an error during replication.

Mutagens

Environmental factors and chemical carcinogens (such as base analogs, alkylating agents, free radicals, and intercalating agents) that damage DNA and cause bases to mispair.

Wobble Pairings

Non-standard base pairings, such as between thymine and guanine, or between cytosine and adenine when adenine gains an extra hydrogen through protonation.

Epigenetics

The study of changes in gene activity that occur without altering the underlying DNA nucleotide sequence, determining whether genes are turned on or off.