LECTURE 9 - Mutations Flashcards
(41 cards)
MUTATION
- heritable or not?
- changes in the ____ sequence or ____ ____ of an organism
- 2 main types?
- heritable
- DNA
- genetic information
- Gene Mutations
- Chromosomal Mutations
GENE MUTATIONS
- mutations involving HOW MANY of ____ (2)?
- 2 types? + DIFFERENCE
- involves one or a few BASES
- affects one or a few GENES
- Base Pair Substitutions
- changes in the identity of a base pair within a DNA sequence - Frameshift Mutations
- changes in the reading frame of a DNA sequence as a result of an addition or a deletion of a base
GENE MUTATIONS - Base Pair Substitutions
- 2 main types and difference?
- covers WHAT type of substitution?
+ WHEN + its 3 types + differences?
- Transition (purine to purine/pyrimidine to pyrimidine)
- Transversion (purine to pyrimidine & vice versa)
- covers AMINO ACID SUBSTITTUION (changes in identity of amino acid coded AFTER a base pair substitution)
a. same sense mutation (mutated codon codes for the same amino acid)
b. missense mutation - mutated codon codes for a different amino acid)
c. nonsense mutation - mutated codon becomes a stop codon
GENE MUTATIONS - Frameshift Mutations
- 2 main types and differences?
+ directional shift?
- Base deletion - frameshift to the right
- Base addition - frameshift to the left
WHAT do you call the complete set of chromosomes in a cell?
+ notation for diploid & haploid
Genome (X)
haploid = genome = X
diploid = 2X
4 CONFIGURATIONS of chromosomes during meiosis?
I - univalent
II - bivalent
III - trivalent
IIII - quadrivalent
CHROMOSOMAL MUTATIONS
- occurs when HOW MANY of _____ are lost or gained by an organism?
- 3 TYPES + difference?
- one, a fer, or a whole set of chromosomes
- Euploidy (numerical)
- addition/loss of WHOLE SET of chromosomes - Aneuploidy (numerical)
- addition/loss of ONE or FEW chromosomes - Structural Aberrations
- changes in the structure of chromosomes
HOW MANY are the CHROMOSOME SETS of the ff ploidy level?
- Monoploid
- Diploid
- Pentaploid
- Heptaploid
- Octaploid
1.) 1 set
2.) 2 sets
3.) 5 sets
4.) 7 sets
5.) 8 sets
CHROMOSOMAL MUTATIONS - Structural Aberrations
- 4 main examples?
- LAGGARD
- chromosome that lags behind during anaphase; nasa gitna pa rin si chromosome - BRIDGE
- 2 homologous chromosomes are still connected during anaphase - RING
- product of TRANSLOCATION
- chromosome that forms a circular structure instead of a linear that occurs during QUADRIVALENTS (4 arms cross over) - CHAIN
- product of TRANSLOCATION
- in QUADRIVALENTS: only 3 out of 4 arms undergo crossing over
CHROMOSOMAL MUTATIONS - Euploidy
- 4 types?
- Monoploidy (one set of chromosome)
- Polyploidy (more than 2 sets of chromosome)
- Autotetraploidy (has 4 identical sets of chromsomes)
- Allotetraploidy (has 4 different sets of chromsomes)
CHROMOSOMAL MUTATIONS - Euploidy
MONOPLOIDY
- monoploid genome?
- synapsis configuration (1)?
- segregation at anaphase I?
- cytological abnormalities (1)?
- gametes?
- 1X = (A,B,C,D) ; ONE SET of chromosome are present
- 4 I (4 univalents)
- Laggards at anaphase I
- irregular
- sterile gametes
CHROMOSOMAL MUTATIONS - Euploidy
POLYPLOIDY
- 1 example?
+ its…
- triploid genome?
- synapsis configuration (3)?
- segregation at anaphase I?
- cytological abnormalities (2)?
- gametes?
TRIPLOIDY
- 3x = (A,B,C,D) (A,B,C,D); THREE SET of chromosome are present
- 4 III
- 4 II & 4I
- 12 I
- irregular
- Laggards in Anaphase I (due to I’s)
- Chains in Diakineses (due to III’s)
- mostly sterile, some fertile
CHROMOSOMAL MUTATIONS - Euploidy
AUTOTETRAPLOIDY
- tetraploid genome?
- synapsis configuration (4)?
- segregation at anaphase I (2)?
- cytological abnormalities (3)?
- gametes?
- 4X = (A,B,C,D) (A,B,C,D) (A,B,C,D) (A,B,C,D)
- 4 IV
- 4 III & 4 I
- 8 II
-16 I - Laggards in Anaphase I
- Chains and Rings in Diakineses
- regular if (II and IV)
- irregular (if I and III)
- some sterile, some fertile
CHROMOSOMAL MUTATIONS - Euploidy
ALLOTETRAPLOIDY
- tetraploid genome?
- synapsis configuration?
- segregation at anaphase I?
- cytological abnormalities?
- gametes?
- 4X = (A,B,C,D) (A,B,C,D) (E,F,G,H) (E,F,G,H)
- 8 II
- regular
- none (only more II at diakinesis compared to normal)
- fertile gametes
ANEUPLOIDY occurs because of??
+ which can happen in 2 ways….
NON-DISJUNCTION
- Bivalents fail to separate properly during meiosis I
- Sister chromatics fail to separate during meiosis II
CHROMOSOMAL MUTATIONS - Aneuploidy
- 2 types?
- 6 subtypes?
- ADDITION OF CHROMOSOMES
a. Trisomy
b. Tetrasomy
c. Double trisomy - LOSS OF CHROMOSOMES
a. Monosomy
b. Nullisomy
c. Double Monosomy
CHROMOSOMAL MUTATIONS - Aneuploidy
ADDITION - TRISOMY
- genome?
- synapsis configuration (3)?
- cytological abnormalities (2)?
- gametes?
- has 1 extra copy for a chromosome (2n + 1) :
(A,B,C,D) (A,B,C,D) (A) - 1 III & 3 II
- 4 II & 1 I
- 9 I
- chains and laggards
- n and n+1
CHROMOSOMAL MUTATIONS - Aneuploidy
ADDITION - TETRASOMY
- genome?
- synapsis configuration (3)?
- cytological abnormalities (3)?
- gametes?
- has 2 extra copies for a chromosome (2n + 2) :
A,B,C,D) (A,B,C,D) (A) (A) - 1 IV & 3 II
- 1 III, 3 II, & 1 I
- 5 II
- chains, laggards, & rings
- n, n+1, & n+2
CHROMOSOMAL MUTATIONS - Aneuploidy
ADDITION - DOUBLE TRISOMY
- genome?
- synapsis configuration (2)?
- cytological abnormalities (2)?
- gametes?
- has 1 extra copy for 2 chromosomes (2n + 1 + 1):
(A,B,C,D) (A,B,C,D) (A,B) - 2 III & 2 II
- 4 II & 2 I
- chains and laggards
- n, n+1, & n+2
CHROMOSOMAL MUTATIONS - Aneuploidy
LOSS - MONOSOMY
- genome?
- synapsis configuration?
- cytological abnormalities?
- gametes?
- loss of 1 copy of chromosome (2n - 1):
(A,B,C,D) (A,B,C) - 3 II & 1 I
- laggards
- n & n-1
CHROMOSOMAL MUTATIONS - Aneuploidy
LOSS - NULLISOMY
- genome?
- synapsis configuration?
- cytological abnormalities?
- gametes?
- loss of both copies for a chromosome (2n - 2):
(A,B,C) (A,B,C) - 3 II
- none (only less II at diakinesis compared to normal)
- n-1
CHROMOSOMAL MUTATIONS - Aneuploidy
LOSS - DOUBLE MONOSOMY
- genome?
- synapsis configuration?
- cytological abnormalities?
- gametes?
- loss of one copy for 2 chromosomes (2n - 1 - 1):
(A,B,C) (A,B) - 2 II & 2 I
- laggards
- n, n-1, & n-2
CHROMOSOMAL MUTATIONS - Aneuploidy
- 4 common human disorders
- Down Syndrome
- 3 copies of chromosome 21 (TRISOMY 21)
- 2n+ 1 = 47 (+21) - Klinefelter Syndrome
- has XXY chromosomes
- 2n + 1 = 47 (XXY) - Trisomy X
- 3 copies of chromosome X
- 2n + 1 = 47 (XXX) - Turner Syndrome
- loss of one X chromosome
- 2n - 1 = 45 (XO)
CHROMOSOMAL MUTATIONS - Structural Aberrations
- 4 TERMINOLOGIES
- terminal
- intercalary
- homozygous
- heterozygous
