Chapter 12.1: Rearrangements of Chromosomal DNA Flashcards
Define deletion
removing base pairs
Define duplications
adding base pairs
Define inversions
half-circle rotations of a chromosomal region
What are half-circle rotations of a chromosomal region?
inversions
Define reciprocal translocations
two nonhomologous chromosomes exchange parts
What are two nonhomologous chromosomes exchange parts?
reciprocal translocations
What causes chromosomal rearrangements?
o Deletions, inversions, duplications, and reciprocal translocations come about most often by either of two events: chromosomal breakage or aberrant (illegitimate) recombination at sites of repeated DNA sequences
What type of chromosomal rearrangement occurs o If a single chromosome suffers two double-strand breaks, loss of the fragment between the breaks followed by DNA repair that fuses the remaining broken ends (nonhomologous end-joining) ?
deletion
What type of chromosomal rearrangement occurs If a single chromosome suffers two double-strand breaks
followed by DNA repair that fuses the remaining broken ends (nonhomologous end-joining)
if the intervening fragment rotates by 180°
?
inversion
What type of chromosomal rearrangement occurs o Breakage of two homologous chromosomes or sister chromatids at different locations can result in a if the broken chromosome ends change places before they are brought together by DNA repair?
deletion and a duplication
What type of chromosomal rearrangement occurs when o Breakage of two nonhomologous chromosomes can result in if the broken ends switch places before repair and fusion
reciprocal translocation
What type of chromosomal rearrangement occurs o Crossovers between repeats of the same sequence at two locations on the same chromosome can result in a if the repeats are in the same orientation?
deletion
What type of chromosomal rearrangement occurs when o Crossovers between repeats of the same sequence at two locations on the same chromosome can result in a if the repeats are in opposite orientations
inversion
What type of chromosomal rearrangement occurs o If two homologous chromosomes misalign at repeated sequences and cross over?
deletion and a duplication
What type of chromosomal rearrangement occurs o Crossovers at a repeated sequence on two nonhomologous chromosomes
reciprocal translocations
What are methods to detect chromosomal rearrangements?
o FISH techniques
o Microarrays of genomic DNA can be used to detect deletions or duplications too small to be found by barcoding
Define rearrangement breakpoints
the base pairs at which the rearranged regions begins and ends
What is the base pairs at which the rearranged regions begins and ends?
rearrangement breakpoints
How are rearrangement breakpoints determined?
genome sequencing or PCR
