Chromosome Aberrations

Question 1

Aberrations

Answer 1

abnormalities

Question 2

Polyploidy

Answer 2

embryo has three, four, or more SETS of chromosomes (complete set duplicated)

Question 3

Aneuploidy

Answer 3

the embryo does not have an exact multiple of the number characteristic of that species (only part of that set is wrong)

Question 4

Types of aneuploidy

Answer 4

trisomy and monosomy

Question 5

Triploid

Answer 5

3 sets for polyploidy

Question 6

Tetraploid

Answer 6

4 sets for polyploidy

Question 7

What is polyploidy a result of?

Answer 7

result of unreduced gamete (2n) and a normal gamete (n)

Question 8

Give two examples of how an embryo can become polyploidy:

Answer 8

1. two sperm fertilizing one egg
2. haploid sperm and a diploid egg

Question 9

Chromosome nondisjunction

Answer 9

failure of homologous chromosomes to disjoin correctly during meiosis

Question 10

The probability of nondisjunction in autosomes ______________ with age.

Answer 10

increases

Question 11

If a gamete is fertilized from a nondisjunction in autosomes then what are the results?

Answer 11

trisomy or monosomy

Question 12

Trisomy

Answer 12

one chromosome extra

Question 13

Monosomy

Answer 13

one chromosome absent

Question 14

X-Monosomy

Answer 14

Turners syndrome

Question 15

Turners syndrome

Answer 15

XO; results when one of the X chromosomes is missing in females causes developmental problems

Question 16

Changes in chromosome structure include:

Answer 16

1. deletion
2. duplications
3. inversion
4. translocation

Question 17

Deletion

Answer 17

part of the chromosome is missing

Question 18

What do deletions cause?

Answer 18

permanent loss of genetic material

Question 19

Terminal deletion

Answer 19

deletion close to chromosome end

Question 20

Interstitial deletion

Answer 20

deletion within a chromosome arm

Question 21

Duplication

Answer 21

part of the chromosome is present TWICE

Question 22

Inversion

Answer 22

results in the reversal of the gene sequence

Question 23

What is curly calf syndrome caused by?

Answer 23

this genetic defect is a result of the deletion of a small segment of DNA which contains an essential gene

Question 24

Polled Intersex Syndrome in Goats is caused by…

Answer 24

11.7 kb deletion in the FOX L2 Gene

Question 25

Pseduohermaphroditism in horses is caused by...

Answer 25

200 kb deletion in ECA29 Gene

Question 26

Metafemale

Answer 26

"XXX" affects only females and results in three X chromosomes instead of 2

Question 27

Klinefelter syndrome

Answer 27

"XXY" where males are born with an extra X chromosome

Question 28

Structural abnormalities are...

Answer 28

larger regions of deletion or duplication that increase the likelihood that there will be an associated phenotype

Question 29

How do ringed chromosomes form?

Answer 29

1. break in both arms 2. terminal ends fuse together 3. broken arms fuse together as a ring

Question 30

What percent of ringed chromosomes arise spontaneously?

Answer 30

99% the rest may be formed following genetic damage

Question 31

Translocation

Answer 31

part of one chromosome exchanges place with the corresponding part of a nonhomologous chromosome

Question 32

Paracentric inversion

Answer 32

part breaks in chromosome and reinserts itself into a piece of DNA

Question 33

Pericentric inversion

Answer 33

the centromere breaks in chromosome and is inverted and reinserted in DNA

Question 34

What is tobiano spotting caused by?

Answer 34

an inversion

Question 35

Balanced translocation

Answer 35

not losing any genetic information equal switch between chromosomes

Question 36

Unbalanced translocation

Answer 36

when an offspring inherits a chromosome with extra or missing genetic information from a parent with a balanced translocation

Question 37

What is REEL in horses caused by?

Answer 37

a balanced translocation

Question 38

Balanced translocation in pigs causes what?

Answer 38

smaller litter size and is very common

Question 39

Translocation 1/8 in cattle causes...

Answer 39

slightly lowered fertility

Question 40

Robertsonian translocation

Answer 40

centric fusion

Question 41

What does Robertsonian translocation do?

Answer 41

fragments from non-homologous chromosomes recombine in such a way that a single centromere is retained

Question 42

What does Robertsonian translocation look like?

Answer 42

the centromere is now shared between chromosomes and a fragment is lost