Mutation and evolution Flashcards
(14 cards)
What is the difference between somatic and germline mutations?
Somatic mutations occur in body cells and are not inherited; germline mutations occur in reproductive cells and are heritable
Name three types of gene mutations
Substitution, insertion, and deletion
What type of mutation changes a single amino acid?
Missense mutation
What mutation causes cystic fibrosis?
In-frame deletion of 3 nucleotides
What is a frameshift mutation?
Mutation caused by insertions or deletions that shift the reading frame of the gene
What is the difference between forward, reverse, and suppressor mutations?
Forward changes wild-type to mutant; reverse restores wild-type; suppressor mutation elsewhere restores wild-type phenotype despite original mutation
What are some common mutagens?
X-rays, UV light, chemicals, and transposable elements
How does DNA repair correct mutations?
Through DNA polymerase proofreading, mismatch repair, base-excision repair, nucleotide-excision repair, and direct repair
What is a chromosomal duplication?
A chromosome segment present twice, usually less harmful than deletion
What effect do chromosome inversions have?
They reverse gene order but usually don’t cause gene loss
How do gene duplications contribute to evolution?
Extra copies can mutate to form new genes or become nonfunctional pseudogenes
Why does genome size not correlate with organism complexity?
Because of varying amounts of non-coding DNA and gene regulation differences
What is polyploidy?
Having more than two sets of chromosomes
What is the difference between autopolyploidy and allopolyploidy?
Autopolyploidy is chromosome duplication within a species (often sterile); allopolyploidy is hybridization between species, which can restore fertility over time
