Mutation II Flashcards
describe chromosomal mutations
insertions and deletions on a massive scale, often affecting dozens of genes
4 types of chromosomal mutations
deletions, duplications, inversions, translocations
what do chromosome structure mutations require
require breaking and rejoining of chromosomal DNA (deletions)
describe intrachromosomal mutations
occurs between parts of the same chromosome (deletions and duplications)
describe inversion. where does it occur?
changing the order of genes (can occur between maternal and paternal homologous chromosomes)
describe translocations. where does it occur?
a chunk of one chromosome gets exchanged for a chunk of another chromosome making hybrid chromosomes (can occur between non-homologous chromosomes)
how does unequal crossing over lead to chromosome structure mutations?
unequal crossing over between homologous chromosomes during meiosis can lead to duplications and deletions (often occurs at repetitive sequences the cell thinks are homologous)
what is recombination? how might it lead to chromosome structure mutations?
recombination is intrachromosomal crossing over (rare, happens during meiosis) & it occurs at repetitive sequences the cell thinks are homologous which leads to deletions or inversions
what may cause double stranded DNA breaks? how does this result in chromosome structure mutations?
ionizing radiation causes double stranded DNA breaks, repair of these breaks can lead to translocations
3 potential consequences of chromosome structure mutations
1) can possibly do nothing (exchanging of entire genes)
2) variety of changes in gene expressions (genes placed next to new CREs, CREs lost or duplicated)
3) created truncated proteins by causing frameshifts or deleting exons
4) create new proteins with new functions by duplicating exons or combining exons from different genes
