Evolution - Chromosome Abnormaltiies

Question 1

Trisomy

Answer 1

Describes a diploid organism having an extra copy of a chromosome, majorly in autosomes.

Question 2

Euploidy

Answer 2

This is an organism with a chromosome number an exact multiple of the haploid number for the speices.

Question 3

Types of Euploidy

Answer 3

Triploidy or Tetraploidy

Question 4

Aneuploidy

Answer 4

Abnormal amount of chromosomes in a haploid set

Question 5

Balanced Translocation

Answer 5

Occurs when part of one chromosome has moved to another homologous chromosome.

Question 6

Unbalanced Translocaiton

Answer 6

Aneuploidy when some part of the genome is missing

Question 7

Monosomy

Answer 7

Occurs when an organism is missing a copy of an individual chromosome

Question 8

How does monosomy compare to trisomy?

Answer 8

More common, harmful, and more frequent in spontaneous abortions.

Question 9

What trisomy can result in birth?

Answer 9

13, 18 and 21

Question 10

Down Syndrome

Answer 10

This is trisomy 21 affecting intellectual capabilities and heart conditions

Question 11

What does trisomy 21 result in?

Answer 11

Shorter stature due to failure of skeletal system development, poor muscular tone and shortened life span.

Question 12

What causes trisomy in down syndrome?

Answer 12

Non-disjunction

Question 13

Non-disjunction

Answer 13

This is where chromosomes fail to split in meiosis, one gamete containg two copies and the other none.

Question 14

What does 21 non-disjunction result in?

Answer 14

Trisomy 21 and mosomy 21, the progeny depending on fertilisation.

Question 15

How much trisomy 21 end in spontaneous abortion?

Answer 15

3/4.

Question 16

Amniocentesis

Answer 16

Can be used to detect abnormaltiies, where cells are obtained by a needle trough the uterus.

Question 17

What is meiotic chromosome behaviour dependet on?

Answer 17

Chiasmata formation and arm pairing

Question 18

What happens to meiotic chromosomes in trisomy?

Answer 18

Trivalent forms, with two centromeres point to one pole whilst the other to opposing pole

Question 19

Why do sex chromosome abnormalities have less effect?

Answer 19

Because Y contains few functional genes, and most X-linked genes are silenced anyways

Question 20

Examples of Sex Chromosome Abnormalities?

Answer 20

Klinefelter Syndrome(47XX7)
Turner Syndrome (45, x)

Question 21

Examples of autosomal abnormalities?

Answer 21

Cri-du-chat
Prader-Willi Syndrome

Question 22

Klinefelter Syndrome

Answer 22

Seen in males, leading to taller infertile cases, with mental impairment and enlarged breasts

Question 23

Turner Syndrome

Answer 23

Results in no sexual maturation, seen in females, with average mental capabiltiies, heavily selected against(99.9% abortions)

Question 24

Cri-Du-Chat Syndrome

Answer 24

Results from either 5p deletions, being a trisomy condition

Question 25

What might cause Nondisjunction?

Answer 25

Variety of envrionmental effects, like smoking, alcohol, fertility drugs, pesticides and radiation.

Question 26

What increases aneuploidy eighfold?

Answer 26

Bisphenol A concentrations increases, found in plastics.

Question 27

Deletions

Answer 27

Removals of a segment

Question 28

When are deletions most harmful?

Answer 28

The larger they are.

Question 29

Small deletions...

Answer 29

Viable in normal homologs that are heterozygous, often leath l in homozygous

Question 30

How do deletions form?

Answer 30

Breakage and reunion, the broken ends (one contains telomere and one centromere) fuses, where the deleted part is lost

Question 31

Ectopic Recombination

Answer 31

Homologous sequence recombination not at the same posiiton on homologous chromosome.

Question 32

Duplications

Answer 32

Where a part of a chromosome is duplicated.

Question 33

What causes further repeats of deletions?

Answer 33

Unequal Crossing(a type of ectopic recombination)

Question 34

Example of deletions?

Answer 34

Hemoglobin

Question 35

What causes RG Colour Blindness?

Answer 35

Unequal crossing

Question 36

Where are the blue and red/green pigments found?

Answer 36

7q22ter and Xw28( seperated by 5cm)

Question 37

Why are red-green pigments susecpetible to crossover?

Answer 37

Similar in amino acid sequence and duplicated togethers.

Question 38

Chimeric Genes

Answer 38

This is the joining of two or moe genes, originally coded for seperate or same protines.

Question 39

Postiion effects

Answer 39

This results when through rearrangement, genes acquire new neighbouring genes, which affect their expressiion.

Question 40

When might position effect variegation occur?

Answer 40

Whne a gene is silence through abnormal juxtaposition with heterochromatin

Question 41

What causes postiion effects?

Answer 41

Chromosome aberration moving wild type gene from euchromatin to near the heterochromatin

Question 42

Polyploidy

Answer 42

Where in higher plants, a genome in a species is composed of multiple sets of chromosomes

Question 43

Difference between haploid and monoploid?

Answer 43

Mono is basic set of chromosome, multiplied in a polyploid species Haploid is the set present in a gamete regardless of chromosome number in species.

Question 44

Process of meiotic bivalency?

Answer 44

Species contains 18 chromoms, 9 bivlaents, gametes recieving one from each bivalent.

Question 45

Sexual Polyploidization

Answer 45

This is a meiotic process with formation of unreducedgametes.

Question 46

Asexual Polyploidization

Answer 46

Results from endoreplication doubling after mitotic doublig

Question 47

What are the two casues of polyploidy?

Answer 47

Asexual and Sexual

Question 48

Two types of polyploidy?

Answer 48

Autopolyploidy and Allopolyploidy

Question 49

Autopolyploidy

Answer 49

Derived from a single diploid ancestor

Question 50

Allopolyploidy

Answer 50

Complete chromosomes sets from different ancestratl species.

Question 51

Chromosome Abnormalities

Answer 51

Change in number or structure of a chromsome.

Question 52

How is monosomy and trisomy written?

Answer 52

2n-1 and 2n+1 respectively.

Question 53

Why does trisomy often result in spontaneous aboriton?

Answer 53

Over expression of genes

Question 54

Non-disjunction in meiosis 1...

Answer 54

In meiosis 2 generation, one cell with 6 sister chromatids and one with 2, where the 4 gametes are two trisomy and two monsomy.

Question 54

Non-disjunction in meiosis 2...

Answer 54

One homolgoous chromosome fails to split why the second cell is normal, resulting in one trisomy and one monosomy, with two normal gametes.

Question 55

What determines gender?

Answer 55

The presence or absence of the Y chromosome.

Question 56

What deletions cause Cri Du Chat and Prader-Willi?

Answer 56

chromosome 5 and 15q1.12 deletion.

Question 57

What determines angelman and prader willi syndomre?

Answer 57

Impriting.

Question 58

Down syndrome inheritance??

Answer 58

Individual carrying translocation between 14 and 21 When have child with norma individuals, the normal produces normal gametes and the translocation carrier abnormal gametes.