ch 8: chromosome mutations Flashcards
dominant-negative
a mutation which suppresses/overrides the function of the wild-type gene
endosymbiotic theory
a mitochondria and chloroplasts arose independently about 2 billion years ago from free-living protobaceria
-DNA resembles DNA seen in bacteria
-presence of a unique genetic system capable of organelle-specific transcription and translation
mitochondrial replacement therapy (MRT)
nucleus from one oocyte with defective mitochondria is removed and transferred to an enucleated egg containing normal mitochondria
aneuploidy
organism gains or loses one or more chromosomes but not grain of a complete set
euploidy
complete haploid sets of chromosomes are present (normal)
polyploidy
more than two sets are present (3n, 4n, etc)
nondisjunction
chromosomes don’t split during meiosis leaving daughter cells with too many or too few chromatids
monosomy
2n-1
-ex: turner syndrome (45,X)
trisomy
2n+1
-ex: down syndrome (47, 21+)
systemic regions
chromosomal regions in different species that contain much of the same content and arrangements of orthologs (genes with similar sequences present in different species)
autopolyploidy
each set of chromosomes is identical to the parent species
alloployploidy
resulting from hybridizing two closely related species
-a fertile AABB tetraploid is produced
deletion
when a chromosome breaks in one or more places and a portion is lose (deficiency)
cri de chat syndrome
46, 5p-
(some of p arm on chromosome 5 is missing)
duplication
any part of genetic material, single locus or large segment, is present more than once in the genome
gene redundancy
multiple copies of same gene sequences
gene amplification
amount of rDNA is increased without permanent changes in DNA
inversion
segment of a chromosome is turned around 180 degrees within a chromosome with no loss of genetic information just rearrangement of linear gene sequence
paracentric inversion
if centromere is not a part of rearrangement
pericentric inversion
if centromere is part of inverted segment
inversion geterozygotes
one member of homologous pair has inverted segment, other is normal
translocation
movement of a chromosomal segment to a new location in genome
reciprocal translocation
exchange of segments without loss of genetic information
