Whole Chromosome Mutations

Question 1

What are the two major categories of whole chromosome mutations?

Answer 1

Aneuploid mutations

Euploidy mutations

Question 2

What are aneuploid mutations?

Answer 2

Aneuploid mutations - change the karyotype by a fraction of a set, such as one extra chromosome or one missing chromosomes

Question 3

What are euploidy mutations?

Answer 3

Euploidy mutation - change the karyotype by the whole set!

Question 4

Changes in the number of chromosomes in eukaryotes result from _______ or ______.

Answer 4

Changes in the # of chromosomes are the result of:

• accidents of nuclear division
• result from inter-species fertilization (and the consequences of these fertilizations)

Question 5

What does the term 1X mean?

Answer 5

1X = one complete set of chromosomes

Question 6

What does the term 2X mean?

Answer 6

2X = two complete sets of chromosomes

Question 7

Normal diploids are _____.

Answer 7

Normal diploids are 2X and have two complete sets of chromosomes.

Question 8

True or False:

Aneuploidy is a condition in which the chromosome number of an individual is NOT an exact multiple of the ‘2X’ number of chromosomes.

Answer 8

False:

Aneuploidy is a condition in which the chromosome number of an individual is NOT an exact multiple of the ‘1X’ number of chromosomes.

Question 9

ANEUPLOIDY

Creating genetic imbalance by having an extra chromosome is like having a big duplication.

Missing a chromosome is like _____

Answer 9

Creating genetic imbalance by having an extra chromosome is like having a big duplication.

Missing a chromosome is like having a big deletion.

Question 10

When is an aneuploid called monosomic?

Answer 10

An aneuploid is called monosomic because there is only one copy of the relevant chromosome.

Question 11

When is a aneuploid called nullisomic?

Answer 11

An aneuploid is called nullisomic when there is no copy of the relevant chromosome.

Question 12

Tetrasomic

Answer 12

When an aneuploid has two extra copies of the same chromosome

Question 13

What are the sources of most aneuploid errors?

Answer 13

They are errors in INDIVIDUAL chromosome’s segregation, either during mitosis or meoisis.

Question 14

What is primary non-disjunction?

Answer 14

If CHROMOSOMES fail to go to opposite poles at the FIRST MEIOTIC DIVISION, this is called primary non-disjuction.

Question 15

What is the most common source of aneuploidy?

Answer 15

Primary non-disjunction

Question 16

Primary non-disjunction produces how many abnormal products?

Answer 16

Primary non-disjunction produces 4 abnormal products.

Question 17

What is secondary non-disjunction?

Answer 17

When chromosomes go to opposite poles in first meiotic division but SISTER CHROMATIDS fail to go to opposite poles during SECOND MEIOTIC DIVISION.

Question 18

For secondary nondisjunction, how many of the four products are abnormal?

Answer 18

Two (of the four)

Question 19

What is mitotic non-disjunction?

What does it produce?

Answer 19

Mitotic non-disjunction occurs if sister chromatids fail to go to opposite poles during mitosis.

This produces two abnormal nuclei.

Question 20

Another source of aneuploidy is _______ ______ ____.

This produces one normal cell and one cell that is missing a chromosome.

Answer 20

Another source of aneuploidy is mitotic chromosome loss.

This produces one normal cell and one cell that is missing a chromosome.

Question 21

What is trisomy?

Answer 21

Trisomy is the condition of having an extra copy of one chromosome.

Question 22

What are euploids?

Answer 22

Organisms that have exact multiples of the monoploid number.

Question 23

Euploid changes are due to:

Answer 23

Euploid changes are due to:

• failure of nuclear division
• result of inter-species fertilization and its consequences

Question 24

What are polyploids?

Answer 24

Individual with more than 2 sets of chromosomes