Chromosomal Mutants

Question 1

Karyotype

Answer 1

Metacentric – middle
Submetacentric – close to middle
Acrocentric – close to end
Telocentric – end

Question 2

Chromosomal Deletions RF

Answer 2

no recombination in deletion

• crossovers closer together
• higher RF

Question 3

Chromosome Deletions Recessive Alleles

Answer 3

genes lost in deletion = null loss of function alleles

Question 4

Chromosome Deletion Polytene Chromosomes

Answer 4

bubble

- bottom strand = deletion

Question 5

Chromosome Deletion PCR Analysis

Answer 5

primers closer together b/c deletion

- see product from deletion chromosome

Question 6

Chromosome Duplications - Types

Answer 6

Tandem = close + direct
Displaced = far + direct
Reverse = close + inverted

Question 7

Chromosome Duplication Polytene Chromosomes

Answer 7

bubble

- top strand = duplicated

Question 8

Paracentric Inversion

Answer 8

• NOT include centromere
• centromeres pulled apart on same strand
  DRAW OUT

Question 9

Pericentric Inversion

Answer 9

• include centromere
• centromeres pulled apart on opposite strands
  DRAW OUT

Question 10

Effect of Inversions/Translocations

Answer 10

• next to new DNA
• split DNA into 2 loss of functions
• recombination in inversion = non-viable gametes

Question 11

Non-Reciprocal Translocation

Answer 11

region of one chromosome insert into another

Question 12

Reciprocal Translocation

Answer 12

regions of chromosomes switched btwn pair of homologous chromosomes

Question 13

Reciprocal Translocations - Adjacent 1

Answer 13

• horizontal division

- inviable gametes = missing info

Question 14

Reciprocal Translocations - Adjacent 2

Answer 14

• vertical division

- inviable gametes = missing info

Question 15

Reciprocal Translocations - Alternate segregation

Answer 15

• translocated chromosomes one way
• normal chromosomes other way
• viable gametes = all info

Question 16

Aneuploidy Types

Answer 16

Normal = 2n 
Nullsomy = 2n-2 (loss of one homologous chromosome)
Monosomy = 2n-1 (loss of single chromosome)
Trisomy = 2n+1 (extra chromosome)
Tetrasomy = 2n+2 (extra pair chromosomes)

Question 17

Mitotic Nondisjunction

Answer 17

both sister chromatids pulled to one pole

Question 18

Nondisjunction of X Chromosome

Answer 18

Male = loss of function allele

- gynandromorphs

Question 19

Nondisjunction at Meiosis I

Answer 19

gametes –> fertilized

• 2 trisomy (both homologs)
• 2 monosomy

Question 20

Nondisjunction at Meiosis II

Answer 20

gametes –> fertilized

• 2 normal
• 1 trisomy (one homolog)
• 1 monosomy

Question 21

Uniparental Disomy

Answer 21

• only 1 parent heterozygous for mutant –> progeny have both mutant alleles
• nondisjunction at meiosis II
• 1 trisomy (one homolog – 2 mutant allele)
• nondisjunction = 2 mutant alleles + normal allele

Question 22

Polyploidy

Answer 22

Genome duplications

• change in #of sets of chromosomes
• 2n –> 3n –> 4n

Question 23

Autopolyploidy - Mitotic

Answer 23

• 2n
• replicate
• Colchicine (MT inhibitor) = no division
• 4n

Question 24

Autopolyploidy - Meiotic

Answer 24

2n –> duplicate

• no segregate at meiosis I (all to one pole)
• meiosis II – 2 gametes (2n)
• fertilization = triploidy (3n) —- unbalanced/inviable

Question 25

Allopolyploidy

Answer 25

• fusion gametes 2 distinct species
• hybrid (haploid each chromosome) (2n)
• meiosis = inviable gametes (no homologous)

Question 26

Amphidiploid

Answer 26

hybrid (2n) –> colchicine induce autopolyploidy –> 4n

• meiosis = viable gametes (homologous pair)