Lec 5-2

Question 1

Types of chromosome mutations

Answer 1

Rearrangements

Aneuploidy

Polyploidy

Question 2

Rearrangements

Answer 2

Mutation of structure

Parts of chromosome are duplicated, deleted, or inverted

Question 3

Aneuploidy

Answer 3

Mutation of number

One or more chromosomes are added or deleted

Question 4

Polyploidy

Answer 4

Mutation of number

Complete sets of chromosomes are added

Question 5

Types of chromosome rearrangements

Answer 5

Duplication

Deletion

Inversion

Translocation

Question 6

Causes of chromosome rearrangements

Answer 6

Crossover error or double stranded DNA breaks

Question 7

Double stranded DNA breaks (dsDNA)

Answer 7

Can cause cell death

Question 8

chromosome rearrangements

Repair machinery

Answer 8

Tries to repair but sometimes makes mistakes

Question 9

Duplication

Answer 9

Section is duplicated

Question 10

Deletion

Answer 10

Section is deleted

Question 11

Inversion

Answer 11

Segment is turned 180 degrees

Question 12

Translocation

Answer 12

A segment moves from one chromosome to a different homologous chromosome or to another place on the same chromosome

Question 13

Causes of duplication and deletion

Answer 13

Unequal crossing over

Question 14

Duplication and deletion causes

Answer 14

Red/green colour blindness

Men affected more than women

Question 15

Duplication and deletion cause

Answer 15

Chromosome loops during prophase 1

One chromosome is normal, the other has deletion

The normal chromosome must loop in order for the homologous sequence to of the chromosomes to align

Question 16

Homozygous deletions

Answer 16

Often lethal

Question 17

Heterozygous deletions

Answer 17

If centromere is deleted, whole chromosome is lost

Can cause two copies of a gene to be needed for proper function

Question 18

Haploinsufficiency

Answer 18

One copy of a gene is not enough

Question 19

Duplications are important for

Answer 19

Evolution

Question 20

Duplication evolution example

Answer 20

Gene A only needs one copy to function
The second copy from duplication is free to mutate

Question 21

Paracentric inversions

Answer 21

Next to the centromere

Question 22

Paricentric inversions

Answer 22

Arounds the centromere

Question 23

Problems from inversions

Answer 23

Breaks may occur within a gene or regulatory region of a gene

Reduces rate of recombination during meiosis

Question 24

Consequences of inversions during meiosis

Answer 24

Heterozygotes will encounter chromosome alignment problems during prophase 1

Loop forms

Creates aberrant chromosome

Recombinant chromatid will have chromosomes lacking many genes and will not be viable

Question 25

Inversions may play a role in

Answer 25

Evolution

Question 26

Translocations

Answer 26

Movement of genetic material between non-homologous chromosomes

Break may occur within a gene or regulatory region of a gene

Possible change in expression due to positional effects

Question 27

Aneuploidy

Answer 27

Deletion of centromere during mitosis or meiosis (loss of chromosome)

Usually lethal

Question 28

Nondisjunction

Answer 28

Failure of homologous chromosomes to separate during mitosis/meiosis

Question 29

Genetic mosaicism

Answer 29

Produces a gyandromorph

Question 30

Gynandromorph

Answer 30

Has multiple phenotypes for a trait

Question 31

Polyploidy

Answer 31

Having more than 2 sets of chromosomes

Question 32

Autopolyploidy

Answer 32

From single species

From nondisjunction in mitosis or meiosis

Question 33

Allopolypoloidy

Answer 33

From two species

Hybridization between two species followed by chromosome doubling

Question 34

Autotriploid

Answer 34

3n

Question 35

Significance of polyploidy

Answer 35

Can lead to evolution: may give rise to new species