Chapter 4c: Variations in Genome Structure: Changes in Chromosome Number

Question 1

addition or subtraction of one or more chromosomes

Answer 1

aneuploidy

Question 2

gain of chromosome/s

Answer 2

hyperploidy

Question 3

Trisomy

Answer 3

2n + 1

Question 4

double trisomy

Answer 4

2n + 1 + 1

Question 5

Tetrasomy

Answer 5

2n + 2

Question 6

loss of chromosome/s

Answer 6

hypoploidy

Question 7

monosomy

Answer 7

2n - 1

Question 8

double monosomy

Answer 8

2n - 1 -1

Question 9

nullisomy

Answer 9

2n - 2

Question 10

2n = 47
44 XX / XY + 21
- extra copy of chromosome 21

Answer 10

Trisomy 21

Question 11

extra copy of chromosome 18
Life expectancy
– 52.5% (or 5 in 10) may live longer that 1 week
- 12.3% (1 in 10) may live longer than 5 years
- 1 year survival is rare

Answer 11

Trisomy 18 – Edwards Syndrome

Question 12

47, XXY
- trisomic disorder
- phenotypically male with feminine characteristics
> enlarged breast
> female pubic pattern
> wide hips

Answer 12

Klinefelter’s Syndrome

Question 13

47, XX / XY, +13
- small head
- cleft
- absent eyebrows

Answer 13

Trisomy 13 – Patau Syndrome

Question 14

2n = 44, XO
- affects females
- one of the sex chromosomes is missing or partially missing

Answer 14

Monosomy X (Turner Syndrome)

Question 15

Effects of Nullisomics (in plants)

Answer 15

• dwarf
• less tillering
• female fertile
• male sterile
• awnless

Question 16

Origin of Aneuploids

Answer 16

§ Loss of chromosomes
§ Non-disjunction of Chromosomes and chromatids
§ Irregularities in chromosome distribution
§ formation of multiple spindles

Question 17

Behavior/Effects of aneuploidy
* __ - change in chromosome number/ association
* __ - sterility due to imbalance
*Change in __

Answer 17

• Cytological
• Genetic
• phenotype

Question 18

chromosome mutation resulting in a change in the whole genome

Answer 18

euploidy

Question 19

only one copy of the genome due to the early separation of chromatids

Answer 19

Monoploidy (X)

Question 20

Detection for monoploidy (x)

Answer 20

*morphological
*cytological
*highly sterile

Question 21

with more than two sets of genome

Answer 21

polyploidy

Question 22

• most common in plants which are asexually propagated and infrequent in animals
• For sexually reproducing organisms, sex chromosome balance must be maintained
• exception: oyster with both diploid and triploid chromosome numbers

Answer 22

polyploidy

Question 23

Detection for polyploidy

Answer 23

• change in morphology
• change in fertility
• change in interspecific crossability

Question 24

examples of Triploid Plants (3n)

Answer 24

• Banana
• apple
• potato

Question 25

unrelated genomes (AABB)

Answer 25

Allopolyploidy

Question 26

belonging to the same genome ( AAA)

Answer 26

autopolyploidy

Question 27

Origin of Autoploids

Answer 27

• Arise spontaneously - nondisjunction in mitosis/meiosis
• restitution nucleus
• unreduced gametes
• can be induced