Genetics Week 15

Question 1

What are traits influenced by

Answer 1

Genetic and environmental factors

Question 2

How can we help in disease prevention and treatment

Answer 2

By identifying the impact of gene and environmen

Question 3

What do twin and adoption studies help to estimate

Answer 3

Genetic and environmental nfluences

Question 4

How are disease with low hereditary influences best prevented

Answer 4

Through lifestyle changes

Question 5

Name the 2 types of twins

Answer 5

-Monozygotic
- Dizygotic

Question 6

What do Monozygotic twins develop from

Answer 6

A single embryo that splits ,

Question 7

What do Dizygotic twins result from

Answer 7

Result from 2 seperate eggs fertilised by different sperm, they share 50% of DNA

Question 8

If both twins share a trait they are ….

Answer 8

Concordant

Question 9

If both twins do not share a trait they are……

Answer 9

Discordant

Question 10

What does intraclass correlation coefficient measure

Answer 10

The similarity in traits between between twin pairs

Question 11

How is Heritability estimated

Answer 11

Using the difference in concordance rates between MZ and DZ twins

Question 12

Name and describe the 3 limitations of twin studies

Answer 12

• Environmental Bias: Mz twins more often experience same environemtn than DZ , overestimating genetic influence
  -Biological difference: Somatic mutations and epigentic changes can make MZ twins less fully identical
• Small sample size

Question 13

Name only the 3 limitations of Twin studies

Answer 13

• Environmental bias
  -Biological differences
  -Small sample sizes

Question 14

What is the purpose of Adoption studies

Answer 14

• Used to estimate genetic contribution to multifactorial traits

Question 15

What does Adoption studies compare

Answer 15

• Compare disease rates in adopted childern with and without a biological parent affected by the disease

Question 16

What are the Limitations of Adoption studies

Answer 16

-Parental environment may have long lasting effects
-Adoption agencies may match adoptive parents to biological parents based on socioeconomic favtors, exaggerating genetic influence
-

Question 17

Compare Adoption studies with twin studies

Answer 17

Theyboth help estimated genetic influenc but it does not provide definitice proof or identify specific genes
- Both methods reuqire caution when interpreting results

Question 18

Most Congenital Malformations are..

Answer 18

Multifactorial

Question 19

Give and example of a congenital malformation that is easily treatable

Answer 19

• cleft lip

Question 20

Give an example of a congenital malformation that has severe consequences

Answer 20

Neural tube defects

Question 21

Name the genes that some congenital malformations are linked to

Answer 21

• HOX, PAX,TBX genes
• RET proto-oncogene

Question 22

Give examples of Environmental factors that can cause congenital malformations

Answer 22

Drugs and chemicals
- Retinoic acid
-Thalidomide
Rubella(Maternal infections)

Question 23

What is alzheimers characterized by

Answer 23

• Memory loss
  -Progressive dementia
  -Amyloid plaques
  -Neurofibrillary tangles

Question 24

What does alzheimers lead to

Answer 24

• Neuronal loss and death

Question 25

Name three key genes involved in Alzheimers

Answer 25

• PSEN1(presenilin 1 )
  -PSEN2
  -APP

Question 26

Explain how PSEN1 and PSEN 2 mutations lead to excess amyloid plaque formation, which is a feature of Alzheimers

Answer 26

• Distrupts amyloid-B(beta) processing

Question 27

What does APP gene muations lead to in Alzheimers

Answer 27

• Leads to abnormal cleavage and amyloid buildup

Question 28

What Disorder increases the risk of early onset Alzheimers

Answer 28

• Downsyndrome

Question 29

What gene is a risk factor for early onsent Alzheimers
- Name is alleles
- which of its alles increase the risk of Alzheimers

Answer 29

Apolipoprotein(APOE)
- 2, 3, 4
- Allele 4 increases the risk of getting Alzheimers