Complex Trait Inheritance

Question 1

what is schizophrenia (spectrum disorder)?

Answer 1

period in which a person in unable to distinguish real v. unreal experiences

Question 2

when is schizophrenia onset?

Answer 2

• insidious onset in late adolescence/ early adulthood
• subtle signs prior to diagnosis

Question 3

what are some hallmarks of schizophrenia?

Answer 3

delusions and hallucinations

Question 4

what is impaired cognition (schizophrenia)?

Answer 4

problems with attention, concentration, memory, declining intellectual performance

Question 5

what are the disorganized symptoms (schizophrenia)?

Answer 5

disorganized thinking and speech, trouble with logical reasoning

Question 6

what are the negative symptoms (schizophrenia)?

Answer 6

loss or decrease in functioning
- does not show simple patterns of inheritance, but shows familial

Question 7

what is your general cognitive ability?

Answer 7

intelligence

Question 8

what is your general cognitive ability measured by?

Answer 8

IQ tests

Question 9

what type of trait is your general cognitive ability?

Answer 9

quantitative

Question 10

does general cognitive ability follow mendelian rules of inheritance?

Answer 10

no

Question 11

what are some characteristics of complex traits?

Answer 11

• polygenic
• quantitative
• polymorphic
• varying phenotypes
• mendels laws
• multifactorial

Question 12

what does it mean to be polygenic?

Answer 12

several or many loci are involved in expression of the trait

Question 13

what does it mean to be polymorphic?

Answer 13

have allele variants

Question 14

greater number of genes =?

Answer 14

greater number of phenotypes

Question 15

what does it mean to be multifactorial?

Answer 15

more variability because environment interacts w/ genotype to produce the phenotype

Question 16

what is liability?

Answer 16

vulnerability, susceptibility, or predisposition for a disorder

Question 17

genotypes above liability threshold have…?

Answer 17

increased risk in expressing the phenotype

Question 18

the multifactorial threshold model is closer to real life because….?

Answer 18

• many factors contribute to a disorder
• effects of each single factor are small but THEY ADD UP
• once factors pass threshold, individual becomes affected by disorder

Question 19

liability is….?

Answer 19

a sum of all multifactorial effects

Question 20

what is the liability threshold model?

Answer 20

binary traits influenced by multiple factors of small effect, an underlying liability distribution exists, with a threshold that divides the population into the two categories for the trait