Chapter 9: Genetic Variation in Individuals and Populations: Mutation and Polymorphism Flashcards
- affects the number of chromosomes in the cell
- mechanism: chromosome missegregation (aneuploidy)
genome mutation
- alter the structure of individual chromosomes
- mechanism: chromosome rearrangement (translocations, inversions, duplications, deletions)
chromosome mutation
- alter individual genes ranging from a change in a single nucleotide to changes affecting millions of base paids
- mechanism: base pair mutation (point mutation, small deletion or insertion)
gene mutation
mutations that convert amino acid-coding codons into premature stop codons
nonsense mutations
mutations convert an amino acid codon into a codon for a different amino acid
missense mutations
mutations which alter the codon sequence but NOT the amino acid
silent mutations
convert a normal stop codon sequence into an amino acid codon
nonstop mutations
addition or deletion where the number of bases is not a multiple of 3
frameshift mutation
defined as the occurrence of at least 2 variant alleles at a locus, each found on chromosomes with >1% frequency in the population
genetic polymorphisms
defined as the occurrence of at least 2 variant alleles at a locus, each found on chromosomes with <1% frequency in the population
rare variants
simplest and most common of all polymorphisms
single nucleotide polymorphisms (SNPs)
stretches of DNA consisting of two, three, or four nucleotides repeated between one and a few dozen times
microsatellites
Which blood type is due to: an allele that produces a gllycotransferase that adds N-acetylgalactosamine to the H antifen?
Type A
Which blood type is due to: a result of a different allele of the same gene that adds a D-galactose to the H antigen?
Type B
Which blood type is due to: a result of another allelic form of the gene which does not produce a functional transferase, so no sugar is added to the H antigen?
Type O
What does the one gene that produces ABO blood groups encode?
a glycosyltransferase
