lecture 10

Question 1

Is weight heritable?

Answer 1

-A heritability of 70 percent has been found across eight European countries.
- Greater shared environment influence for women
-No heritability of weight at birth during the first months. The environment is more important in those early times.
-These genes also influence eating behaviors: enjoyment of food, slowness in eating, food responsiveness.

Question 2

How much variance is explained in GWAS BMI study?

Answer 2

10-15% of the variance is explained and the rest is mostly missing heritability.

Question 3

Animal studies of weight?

Answer 3

1- Obese mice have the mutation allele ob/ob. He is always hungry.
2- In mice hormone leptin reduces appetite and increases energy.
3-Obese mice have defective leptin hormone.
4- Obese humans don’t have this defected leptin hormone.
5-Obesity related traits are highly complex and affected by multiple genes and enviromental stimuli.

Question 4

Personality

Answer 4

Distinctive and relatively stable pattern of behavior, thoughts, motives, and emotions that characterizes an individual.

Question 5

Significance of personality in research?

Answer 5

1- Significant when studying normal behaviors and deciding on psychopathology.
2- Some psychopathologies are extreme versions of normal variation in personality.
3-Genes make a major contribution to personality so as the environment but not “ Shared enviroment”.

Question 6

The big Five

Answer 6

1-Extraversion - Intraversion
2- Neuroticism-Emotional stability
3-Agreeableness- Antagonism
4- Conscientiousness- impulsivity
5-Opennes to experience- resistance to experience

Question 7

The big five facts

Answer 7

1- Big five traits may change over life-span
2- Neuroticism is highest among young adults and then decreases. Conscientiousness lowest and then increases.
3- Heritability range is usually around 30-50%
4-Heritabilities explained by common SNP’s are low (10%) missing heritability.
5-Heritability of personality is not common at birth
6- Heritability in childhood higher than in adulthood. (influence of enviroment increases)

Question 8

Gene- environment life events

Answer 8

1-Controllable events ( getting married)
2- Uncontrollable events ( serious lines)
3-desirable events ( improvement in financial sit)
4-Undesirable events ( death of a child)
-Heritable components for all (except uncontrollable events.) effect are related to genes for personality traits.

Question 9

Sexual orientation findings

Answer 9

1- Not a pure choice, not genetically determined.
2- Higher MZ correlation than DZ correlation.
3- The heritability for sexual orientation in twin studies is about 35%.
4- SNP-based heritability was estimated to be 8-25% of the variation in homosexuality.
5- The more someone is attracted to the same sex the less they will be attracted to the opposite sex in a MISCONCEPTION. (there is no dimension)