Exam 2 part 5 Flashcards
Chromosome mutations
change from normal chromosome structure and/or number
change in gene expression pattern, if organism is viable
detectable through karyotyping
occurs commonly
Euploid
number of chromosomes in individual’s cells is a multiple of normal haploid set
aneuploid
not a multiple of normal haploid set; one or more extra/missing chromosomes
Nondisjunction
homologous chromosomes during anaphase I or sister chromatids during anaphase II do no segregate properly
Nullisomy
both homologous chromosomes are absent
embyronic lethal
Monosomy
one chromosome missing 2n-1
trisomy
one extra chromosome
2n+1
tetrasomy
2 extra chromosomes
2n+2
Trisomy 21 and advanced maternal age
oocytes are arrested in prophase I each moth after puberty, meiosis continues in 1 egg
Monoploidy
one set
Diploidy
2 sets
Polyploidy
at least 2 sets
Ploidy levels
monoploidy
diploidy
polyploidy
Monoploidy vs Haploidy
Monoploidy results from mitosis
Haploidly results from meiosis
autopolyploidy
extra set of chromosomes is identical to noromal haploid set
allopolyploidy
chromosome come from 2 different species to produce a hybrid
endopolyploidy
when only certain cells of an organism are polyploid
how chromosome structure changes occur
by breaks in chromosomes
general errors in recombination
Types of chromosomal structure changes
deletions
duplications
inversions
translocations
Deletion
Part of a chromosome gets looped and breaks, then lost
Consequences of deletion
-if deletion of recessive allele, normal phenotype
-pseudodominance
Haploinsufficiency
Acentric chromosome
Pseudodominance
deletion of a dominant allele and unmasking of recessive allele
acentric chromosome
deletion removes centromere
-nondisjuction
Duplication
Occurs during recombination
results in 2 normal chromosomes, one deletion chromosome, and one duplication chromosome