Module 2 Flashcards
What is chromosomal rearrangement?
A change in the order of base sequences along one or more chromosomes
What two types of large scale events reshape genomes?
) Rearrangements
2) changes in chromosome number
Deletion in DNA sequence
removing of base pair(s)
Duplications in DNA sequence
adding base pairs
inversions in DNA sequence
half-circle, or 180 degree rotation, of a chromosomal region
Reciprocal translocations
two nonhomologous chromosomes exchange parts
Chromosome breakage and subsequent DNA repair can result in which types of chromosomal rearrangements?
All classes of chromosomal rearrangements
What are transposable elements?
DNA sequences that can move from place to place
What is FISH analysis?
Fluorescence in situ hybridization
Deletion; inversion
Crossovers between repeats of the same sequence at two locations on the same chromosome can result in __________ if the repeats are in the same orientation or an _____________ if the repeats are in opposite orientations.
What is spectral karyotyping?
Probes paint each chromosome a different color
What is spectral karyotyping?
robes paint each chromosome a different color
What is multicolor banding?
FISH probes specific for particular regions of chromosomes generate chromosome barcodes
Rearrangement breakpoint
the abnormal juxtapositions of DNA sequences in a chromosome caused by rearrangement; identifies the precise base pairs at which rearranged chromosome segments begin and end
What is haploinsufficiency?
half the normal gene dosage does not produce enough protein for a normal phenotype
Translocation between which chromosomes causes Down Syndrome?
21 and 14
What is a deletion loop?
an unpaired bulge of the normal chromosome that corresponds to the area deleted from the other homolog
Two types of duplications
Tandem and nontandem
What is a tandem duplication?
repeated copies lie adjacent to each other, either in the same order or in reverse order
What is nontandem duplication
AKA dispersed duplication; copies of the region are not adjacent to each other and may lie far apart on the same chromosome or on different chromosomes
What is unequal crossing-over?
recomination resulting from such out-of-register pairing
In Drosophila, tandem duplication of a region of the X chromosome called 16A produces “Bar” mutant phenotype. What do Bar eyes resemble
A kidney bean
What is the difference between pericentric and paracentric inversions?
Pericentric include the centromere; paracentric inversions exclude the centromere
If during anaphase 1, N1 segregates with N2 and T1 segregates with T2, the gametes will be balanced because….?
each gamete will have one copy of each gene