Chapter 6: Chromosome Mutations Flashcards
define aneuploidy
variations in a specific chromosome
define euploidy
complete haploid sets of chromosome are present
multiples of n
define polyploidy
more than two sets of chromosomes are present
more than 2 multiples of the haploid chromosome are found
nondisjunction is the…
disruption of the normal distribution of chromosomes into gametes
Monosomy is a type of _______ and is defined as the…..
aneuploidy
loss of one chromosome
haploinsufficiency
when a single recessive gene is insufficient to provide life-sustaining function for an organism
a trisomy is the
addition of a chromosome
autopolyploidy is the…
addition of one or more sets of chromosomes identical to the haploid compliment of the species
allopolyploidy is the…
combination of chromosome sets from different species
hybridization
what type of chromosomes aberrations change the total amount of genetic information in chromosomes?
- deletions
- duplications
what type of chromosomes aberrations rearranges the genetic material but the information stays the same?
inversions
translocations
translocations occur between
nonhomologous chromosomes
terminal deletions occur…
near one end of the chromosome
intercalary deletions occur…
from the interior of a chromosome
a paracentric inversion…
does not include centromere
a pericentric inversion…
includes the centromere
define alternate segregation
segregation pattern leading to a normal balanced gamete
define adjacent segregation
segregation pattern leading to gametes containing duplications or deficiencies
robertsonian translocation produces
- normal
- normal carrier
- trisomy 21
- lethal
phenotypic variations result from
modifications at the chromosome level
list 3 chromosomal modifications
- change in total chromosome number
- deletion or duplication of genes or chromosome segments
- rearrangements of genetic material
nondisjunction in the first meiotic division results in
no normal zygotes
nondisjunction in the second meiotic division results in
1/2 normal zygotes
down syndrome critical region is found on which chromosome?
chromosome 21
down syndrome occurs due to nondisjunction of
chromosome 21
75% of nondisjunction of chromosome 21 occur during
meiosis 1
what is the source of trisomy in 95% of cases?
the ovum
which two human trisomies survive to term?
- Patau syndrome
- Edwards syndrome
occur at chromosome 13 & 18
familial down syndrome is due to the translocation of…
the bottom part of chromosome 21 onto another chromosome
chromosomal aberrations occur due to…
exposure to chemicals or radiation
what condition results from the segmental deletion of chromosome 5?
cri du chat
duplications may result in
- gene redundancy
- phenotypic variation
- genetic variability
gene amplification is a mechanism to
increase rDNA that codes for rRNA
a crossover between paracentric inversion produces
dicentric chromatid and acentric chromatid
what 2 segregation patterns result from translocation?
- alternate segregation
- adjacent segregation
define alternate segregation
leads to normal and balanced gametes
define adjacent segregation
leads to gametes containing duplications and deficiencies
