population genetics- basics

Question 1

it is clear that some diseases have a major

Answer 1

environmental component

Question 2

Sir William Richard Doll

Answer 2

british physiologist who was a pioneer in research linking smoke to health problem. He was credited for proving that smoking increased chances of lung cancer rand hear disease

Question 3

proof in pictures of disease and enviroment

Answer 3

twins - twin on the right smoked and sunbathed her whole life

Question 4

environmental factors

Answer 4

physical chemical biological

Question 5

genetic

Answer 5

monogenic polygenic

Question 6

how manny human diseases are caused by single gene defects

Answer 6

4000

Question 7

defective enzymes can have a major consequence for

Answer 7

metabolic pathways

Question 8

dominant

Answer 8

vertical pattern of individuals

Question 9

recessive

Answer 9

horizontal patterns of affected individuals

Question 10

autosomal recessive

Answer 10

consanguinity (incest) often between parents

Question 11

autosomal

Answer 11

males and females affected with equal probability

Question 12

X-linked recessive

Answer 12

ales affected, female carriers

Question 13

X linked dominant

Answer 13

all daughter and males are affected

Question 14

mitochondrial

Answer 14

non-mendelian- maternal inheritance

Question 15

Dominant diseases

Answer 15

achondroplasia hungtintons

Question 16

achondroplasia

Answer 16

dwarfism- a bone growth disorder

Question 17

Huntington’s disease

Answer 17

neurofegenerive genetic disorder that affects muscle coordination and leads to cognitive decline and psychiatric probles

Question 18

recessive

Answer 18

sickle cell anaemia CF

Question 19

sickle cell anaemia

Answer 19

blood disorder effecting shape of the red blood cells and therefore their carry of oxygen capacity

Question 20

Cystic fibrosis

Answer 20

autosomal recessive disorder caused by a mutation on a cl- channel- causes thick secretion of mucous and effects the lungs and various other organs

Question 21

X-linked

Answer 21

duchene muscular dystrophy haemophilia

Question 22

duchess muscular dystrophy

Answer 22

muscle degeneration which leads to death

Question 23

hemophilia

Answer 23

when you can’t stop bleeding

Question 24

hemophilia

Answer 24

when you can’t stop bleeding

Question 25

common traits have a

Answer 25

genetic component e.g. twin, family and admixture studies indicate that type 2 diabetes and obesity have genetic components

Question 26

monozygotic twins

Answer 26

40% will have type 2 diabetes if one does

Question 27

dizygotic twins

Answer 27

around 10% will have type 2 if one does

Question 28

Linkage

Answer 28

generally measured from recombination frequency between two markers in crosses- but humans are not ideal organisms for genetic since scientists can’t control who they breed with

Question 29

why are humans not ideal organisms for genetics

Answer 29

can’t control who they breed with

Question 30

markers can be used to

Answer 30

show up genetic disorders

Question 31

markers used to show up genetic disorders

Answer 31

structural rearrangements SNPs RFLPs INDELs

Question 32

SNPs

Answer 32

single nucleotide polymorphism

Question 33

RFLPs

Answer 33

Restriction Fragment Length Polymorphism (RFLP) is a difference in homologous DNA sequences that can be detected by the presence of fragments of different lengths after digestion of the DNA samples in question with specific restriction endonucleases.

Question 34

linkage and statistical analysis

Answer 34

..

Question 35

why has there been huge process in identifying common diseased genes

Answer 35

because genome wide association studies mean we can study a large proportion of the common human variation in one experiment. -GWA studies empty case-control design comparing two large groups (one being affected and the other as a control) -all individuals in each group are genotyped for the majority of common known SNP –> typically around a million Association is then measured using Lod score

Question 36

Lod score

Answer 36

.

Question 37

pedigree symbols

Answer 37

.

Question 38

autosomal dominant -huntington’s -polycystic kidney disease Pedigree

Answer 38

-every affected individual has an affected biological parent -males and females equally likely to be affected -50% chance of recurrence -normally siblings to not transmit to offspring

Question 39

autosomal recessive -CF Pedigree

Answer 39

-males and females are equally affected -recurrence risk of each child- 25% -traits characteristically found in siblings and not parents mating parents may be consanguineous (incest) traits may appear as an isolated event

Question 40

consanguineous

Answer 40

incest

Question 41

x-linked recessive -duchenne -haemophlia Pedigree

Answer 41

-males are much more likely to be affected -trat is never passed from rathe rot son -all affected males in a family are related through their mothers -passed from affected grandfather to carrier daughter

Question 42

mitochondrial -leber hereditary optic neuropathy

Pedigree

Answer 42

-non-mendelian -everyone inherits the condition through the maternal line

Question 43

complications that affect interpretation of pedigrees

Answer 43

1. new mutations
2. penetrance- low penetrance- sufferers would only sometimes produce the symptoms
3. expressivity- patient always expresses some the symptoms of the disease and varies from very mildly affected to very severely affected
4. delayed onset- some diseases do not express themselves until later in life, well beyond reproductive age
5. anticipating 6.imprinting

Question 44

pentrance

Answer 44

e.g. low penetrance- sufferers would onto sometimes produce some symptoms

Question 45

expressivity

Answer 45

patients always express some symptoms of the disease and varies from very mildly affected to very severely affected

Question 46

delayed onset

Answer 46

1. some disease do not express themselves until later life, well beyond reproductive age.

Question 47

how can diseased genes sometimes be identified

Answer 47

sometimes diseases will correlate with a visible chromosomal deletion or rearrangement e.g. translocation or duplication or delegation e.g. may be able to be seen on karyotypes

Question 48

example pedigree of autosomal dominant with incomplete penetrance

Answer 48

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