Chromosomal Abberations 2

Question 1

What is aneuploidy?

Answer 1

Addition or subtraction of one or more chromosomes

Includes conditions like trisomy and monosomy.

Question 2

Define hyperploidy.

Answer 2

Gain of chromosome/s

Examples include trisomy (2n + 1) and tetrasomy (2n + 2).

Question 3

What is the term for the loss of chromosome/s?

Answer 3

Hypoploidy

Includes conditions like monosomy (2n - 1) and nullisomy (2n - 2).

Question 4

What is monosomy X also known as?

Answer 4

Turner Syndrome

Characterized by the chromosomal configuration (2n = 44, XO).

Question 5

List effects of nullisomics in wheat.

Answer 5

• Dwarf
• Less tillering
• Female fertile
• Male sterile
• Awnless

Nullisomics are mutants lacking single pairs of chromosomes.

Question 6

What is euploidy?

Answer 6

Chromosome mutation resulting in a change in the whole genome

Includes monoploidy, diploidy, and polyploidy.

Question 7

What are the two types of polyploidy?

Answer 7

• Allopolyploidy
• Autopolyploidy

Allopolyploidy involves unrelated genomes while autopolyploidy involves the same genome.

Question 8

What is the origin of aneuploids?

Answer 8

• Loss of chromosomes
• Non-disjunction of chromosomes and chromatids
• Irregularities in chromosome distribution
• Formation of multiple spindles

Non-disjunction can occur during meiosis or mitosis.

Question 9

True or False: Polyploidy is more common in animals than in plants.

Answer 9

False

Polyploidy is most common in plants, especially those that are asexually propagated.

Question 10

Fill in the blank: Down Syndrome is an example of _______.

Answer 10

Aneuploidy

Characterized by the chromosome configuration 22IA + I21 + XX or XY.

Question 11

Define triploid plants.

Answer 11

Plants with three sets of chromosomes (3n)

Often sterile due to unbalanced gamete formation.

Question 12

What is the significance of maintaining sex chromosome balance in sexually reproducing organisms?

Answer 12

It is essential for fertility

An exception is the oyster, which can have both diploid and triploid chromosome numbers.

Question 13

What is the result of autopolyploidy?

Answer 13

Arise spontaneously from nondisjunction in mitosis/meiosis

Can also be induced through techniques like chemical treatments.

Question 14

List methods of detection for chromosome number changes.

Answer 14

• Morphological changes
• Cytological changes
• Changes in fertility
• Changes in interspecific crossability

These methods help identify polyploidy and aneuploidy.

Question 15

What chromosome configuration indicates a monosomic condition?

Answer 15

2n - 1

This indicates one less than the diploid number.

Question 16

What does tetrasomy refer to?

Answer 16

2n + 2

Indicates the presence of an extra pair of chromosomes.