Genomic Evolution

Question 1

What percentage of people will suffer from a genetic based disease in their lifetime?

Answer 1

30%

Question 2

What are 2 types of genetic disease?

Answer 2

Chromosomal abnormalities

Single gene disorders

Question 3

What is the name given to non sex chromosomes?

Answer 3

Autosomes

Question 4

How many pairs of chromosomes?

Answer 4

23

Question 5

What can induce a chromosomal abnormality?

Answer 5

Radiation, Chemicals

Errors in replication eg Gaining or loosing a single chromosome

Question 6

What is Downs/ Trisomy 21 examples of?

Answer 6

Trisomy- grain of chromosome to diploid chromosomes

Question 7

What is monosomy?

Answer 7

Loss of a single chromosome

Not tolerated in mammals

Question 8

When was down syndrome discovered and by who?

Answer 8

1966 John Downs

Question 9

What is the type of partial monomy that humans can have?

Answer 9

Cri-Du-Chat syndrome

Severe mental retardation
Physical abnormalities

Question 10

How common is Cri-Du-Chat?

Answer 10

1/50,000 infants

Question 11

What factor in mothers is linked to downs?

Answer 11

Age

The older the mother the higher the chance of Downs

Question 12

Name the 2 types of mutation

Answer 12

1) point mutation

2) insertion/ deletion mutation

Question 13

Define transversion

Answer 13

a point mutation in DNA in which a single (two ring) purine (A or G) is changed for a (one ring) pyrimidine (T or C), or vice versa.

Question 14

Name 3 types of spontaneous Insertion/deletion mutations

Answer 14

Replication errors
Tautomerizations
Deamination

Question 15

Name 3 types of induced Insertion/deletion mutations

Answer 15

Radiation UV
Intercalating agents
base analogues

Question 16

How common are replication errors?

And do they get repaired?

Answer 16

Wrong pair introduced every 10^10 base pairs

Good chance it will be repaired

Question 17

Define tautomeric Shift

Answer 17

Interconverted forms of DNA bases

Question 18

Name 2 examples of tautomeric shift

Answer 18

Amino group of A or C ( NH2) Imino group (NH)

Keto group of G or T ( C+O) Enol group (C-OH)

Question 19

What is deamination?

Answer 19

Loss of amino group

Question 20

What causes induced mutations

Answer 20

Chemical ( broken bonds and bases chemically altered) or Physical ( Radiation, X rays, UV)

Question 21

What are intercalating elements?

Answer 21

Insert themselves between bases

Question 22

Name an example of a intercalating agent?

Answer 22

Ethidium bromide

Question 23

What are base analogues?

Answer 23

Incorporated into DNA

More prone to tautomeric shifts

Question 24

Name an example of a base analogue

Answer 24

Bromouracil - T analogue

Question 25

What classifies single gene defects?

Answer 25

X-linked if on X chromosome

Autosomal if on autosome

Question 26

Cystic Fibrosis is autosomal recessive.

What causes this?

Answer 26

caused by a defective CFTR gene ( cystic fibrosis transmembrane conductance regulator)
CFTR encodes a Cl- ion transporter

Question 27

Name an example of a autosomal dominant gene

Answer 27

Huntington’s disease

progressive neurological degenerative disease

Question 28

Inherited breast cancer accounts for how many of all breast cancer cases?

What gene is mutated?

Answer 28

5%

Mutation sin BRACA 1 or BRACA 2

Question 29

Name an example of a X-linked disease?

Answer 29

Hemophillia

Question 30

What techniques are used to obtain a DNA sample from a fetus and at what weeks?

Answer 30

Amnicentisis - 12th week +

Chorinic Villus Sampling - 8/12th week

Question 31

In vitro fertilisation how can they test the gender before it develops?

Answer 31

PGD

Pre-implantation genetic diagnosis

Question 32

Name the 3 advantages to PGD

Answer 32

detects ~ 100 genetic disorders
Increases success rate of IVF
Gives a choice to the couples

Question 33

How do we get DNA samples from adults?

Answer 33

Blood Sample

Skin biopsy

Question 34

What stain is used to visual chromosome in a light microscope?

Answer 34

Giemsa Stain