Chapter 4b - Variations in Genome Structure (Changes in Chromosome Structure)

Question 1

chromosomal aberrations

Answer 1

1. alterations in number of genes
2. alterations in location of genes

Question 2

alterations in number of genes

Answer 2

• deletions
• duplications

Question 3

alterations in location of genes

Answer 3

• inversions
• translocations

Question 4

• loss of chromosomal segment
• could be homozygous or heterozygous

Answer 4

deletions

Question 5

genetic effects of deletions

Answer 5

• lethal in homozygous and hemizygous condition
• reduced viability
• modified phenotypic ratio
• pseudodominance

Question 6

situation in which the inheritance of a recessive trait mimics a dominant pattern

Answer 6

Pseudodominance

Question 7

due to a deletion in the short arm of chromosome #5

Answer 7

Cri du chat syndrome

Question 8

chromosome 7 loses an end piece

Answer 8

Williams syndrome

Question 9

symptoms of people with Williams syndrome

Answer 9

1. turned up nose
2. wide mouth, small chin
3. poor academic skills
4. developed verbal and musical skills

Question 10

due to repeated portion in a chromosome due to unequal crossing oer or errors in replication

Answer 10

duplication

Question 11

genetic effects of duplications

Answer 11

gene redundancy

Question 12

• occur when parts of chromosomes become detached, turn thruogh 180 degrees and reinserted in such a way that the genes are in reversed order
• arise from chromosome entanglements and breakages during meiotic prophase; also from recombination between transposable elements
• cause linear rearrangement of genes in a chromosome

Answer 12

inversions

Question 13

two types of inversion

Answer 13

1. pericentric inversion
2. paracentric inversion

Question 14

inversion that is situated in a chromosome arm to one side off the centromere

Answer 14

paracentric inversion

Question 15

color pattern due to a large inversion on Equus caballus chromosome 3

Answer 15

tobiano color pattern

Question 16

inversion on Equus caballus chromosome

Answer 16

alter expression of KIT receptor tyrosine kinase

Question 17

inversion where centromere is included

Answer 17

pericentric inversion

Question 18

• involves interchange of blocks of genes between two nonhomologous chromosomes
• linkage relationships between genes change

Answer 18

reciprocal translocation

Question 19

types of reciprocal translocation

Answer 19

1. alternate
2. adjacent 1
3. adjacent 2

Question 20

• translocation places the c-myc protooncogene in the vicinity of the immunoglobulin heavy chain enhancer
• causes overproduction of c-mye

Answer 20

Burkitt’s lymphoma

Question 21

reciprocal translocation involves exchange between what chromosomes

Answer 21

two NON-HOMOLOGOUS chromosomes

Question 22

reciprocal transloctaion between chromosome 2 and 20

Answer 22

Alagille Syndrome

Question 23

reciprocal translocation between chromosome 9 and 22

Answer 23

Philadelphia Chromosome

Question 24

Chromosomal Structure Abnormalities

Answer 24

1. translocation
2. deletion
3. insertion
4. inversion
5. isochromosome
6. derivative chromosome
7. ring chromosome