allelic diseases
different diseases caused by different mutations in the same gene
base excision repair
replacement of one to five contiguous DNA nucleotides, which corrects oxidative damage
conditional mutation
a genotype that is expressed only under certain environmental conditions
deletion
a mutation that removes part of a DNA sequence or part of a chromosome
excision repair
enzyme catalyzed removal of pyrimidine dimers in DNA
exon skipping
a protein that is missing contiguous amino acids because a missense mutation creates an intron splice site
expanding repeat
a short DNA sequence that is present in a certain range of copy numbers in wild type individuals but, when expanded, causes a disease
germline mutation
a mutation that is in every cell in an individual because it was present in the fertilized ovum
gonadal mosaicism
having two or more genetically distinct cell populations in an ovary or testis
insertion
a mutation that adds DNA bases
mismatch repair
checking DNA for misalignment of short, repeated segments
missense mutation
a single-base change (point mutation) that alters a codon so that it specifies a different amino acid
mutagen
an agent that causes mutation
nonsense mutation
a point mutation that changes an amino-acid-coding codon into a stop codon, prematurely terminating synthesis of the encoded protein
nonsense-mediated decay
a response that destroys mRNAs in which nonsense mutations encode shortened proteins that could have toxic effects on the cell
nucleotide excision repair
replacement of up to 30 nucleotides, which corrects several types of DNA damage
point mutation
a single-base change in DNA
polymorphism
a DNA base or sequence at a certain chromosomal locus that varies in a small percentage of individuals in a population
short tandem repeat
a DNA seauence of 2-10 bases that repeats at a specific site in a genome. Used in forensics to distinguish individuals
somatic mutation
a genetic change in a non-sex cell
splice-site mutation
a point mutation at a site in a gene that controls intron removal, resulting in extra or absent amino acids in the protein product
tandem duplication
a copy of a DNA sequence next to the original sequence
transition
a point mutation that replaced a purine or a pyrimidine with a pyrimidine
transversion
a point mutation that replaces a purine with a pyrimidine or vice versa
