Genetics Week 15 Flashcards
What are traits influenced by
Genetic and environmental factors
How can we help in disease prevention and treatment
By identifying the impact of gene and environmen
What do twin and adoption studies help to estimate
Genetic and environmental nfluences
How are disease with low hereditary influences best prevented
Through lifestyle changes
Name the 2 types of twins
-Monozygotic
- Dizygotic
What do Monozygotic twins develop from
A single embryo that splits ,
What do Dizygotic twins result from
Result from 2 seperate eggs fertilised by different sperm, they share 50% of DNA
If both twins share a trait they are ….
Concordant
If both twins do not share a trait they are……
Discordant
What does intraclass correlation coefficient measure
The similarity in traits between between twin pairs
How is Heritability estimated
Using the difference in concordance rates between MZ and DZ twins
Name and describe the 3 limitations of twin studies
- 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
Name only the 3 limitations of Twin studies
- Environmental bias
-Biological differences
-Small sample sizes
What is the purpose of Adoption studies
- Used to estimate genetic contribution to multifactorial traits
What does Adoption studies compare
- Compare disease rates in adopted childern with and without a biological parent affected by the disease
What are the Limitations of Adoption studies
-Parental environment may have long lasting effects
-Adoption agencies may match adoptive parents to biological parents based on socioeconomic favtors, exaggerating genetic influence
-
Compare Adoption studies with twin studies
Theyboth help estimated genetic influenc but it does not provide definitice proof or identify specific genes
- Both methods reuqire caution when interpreting results
Most Congenital Malformations are..
Multifactorial
Give and example of a congenital malformation that is easily treatable
- cleft lip
Give an example of a congenital malformation that has severe consequences
Neural tube defects
Name the genes that some congenital malformations are linked to
- HOX, PAX,TBX genes
- RET proto-oncogene
Give examples of Environmental factors that can cause congenital malformations
Drugs and chemicals
- Retinoic acid
-Thalidomide
Rubella(Maternal infections)
What is alzheimers characterized by
- Memory loss
-Progressive dementia
-Amyloid plaques
-Neurofibrillary tangles
What does alzheimers lead to
- Neuronal loss and death
Name three key genes involved in Alzheimers
- PSEN1(presenilin 1 )
-PSEN2
-APP
Explain how PSEN1 and PSEN 2 mutations lead to excess amyloid plaque formation, which is a feature of Alzheimers
- Distrupts amyloid-B(beta) processing
What does APP gene muations lead to in Alzheimers
- Leads to abnormal cleavage and amyloid buildup
What Disorder increases the risk of early onset Alzheimers
- Downsyndrome
What gene is a risk factor for early onsent Alzheimers
- Name is alleles
- which of its alles increase the risk of Alzheimers
Apolipoprotein(APOE)
- 2, 3, 4
- Allele 4 increases the risk of getting Alzheimers
Name the 3 major Psychiatric disorders
- Schizophrenia, bipolar disorder, Autism spectrum
What are the symptoms of schizophrenia
- Delusions, hallucinations
What are symptoms for Bipolar disorder
- Extreme mood swings
What are symptoms for Autism Spectrum Disorder
- Impaired social interaction, communication difficuties, repetitive behaviors
