Exam 2: Chromosome Variation Flashcards
(25 cards)
G-banding
heterochromatin staining
Q-banding
A-T vs. G-C staining
C-banding
centromeric heterochromatin staining
R-banding
non-heterochromatin staining
What are the more modern tecniques for karyotyping?
SKY and FISH
Submetacentric chromosomes
2 shorter arms and 2 longer arms
Metacentric chromosomes
4 equal length arms
Telocentric chromosomes
2 long arms and no arms on other end
Acrocentroic chromosomes
2 very short arms and 2 very long arms
Order of chromsomes in increasing size
telocentric, acrocentric, submetacentric, metacentric
What are the types of chromosome mutations?
Deletion, duplication, inversion, and translocation
What does chromosome duplication cause?
Unbalanced gene dosage
What needs to happen in chromosome duplications?
The duplicated region must be looped out in roder for homologous sequences of the chromosomkes to align
What are the consequences of duplications?
Abnormal development and evolutionary change
What are the effects of deletions?
Imbalances in gene product, abnormal development, expression of a normally recessive gene (pseudodominance), no expression because both alleles are needed (haplinsufficiency)
Pericentric inversion
Includes the centromere with normal gametes formed in homozygous or heterozygous individuals
Paracentric inversion
Does not include the centromere with reduced recombination in heterozygous individuals with nonviabvle gametes
Robertsonian translocation
Deletion + translocation
What are the causes of aneuploidy?
Deletion of the centromere during mitosis or meiosis, robertsonian translocation, nondisjunction during meiosis or mitosis
Nullisomy
Loss of both homologous chromosomes - non-viable
Monosomy
Loss of single chromosome in homologous pair - sometimes viable
Trisomy
Gain of a single chromosome in a homologous pair - sometimes viable
Tertasomy
Gain of two chromosome in a homologous pair - only viable in sex chromosomes
Primary Down Syndrome
75% random nondojunction in egg formation - more likely in older women
