Genetic basis of behavior _ د.عباس Flashcards
how many perspectives in the study of psychology ?
-six perspectives in the study of psychology
Each perspective provide a ————————— and focus on ———————-
Each perspective provide a different conception of human nature and focus on different cuases of behavior
what’re the six perspectives?
1- The biological perspective 2-The cognative perspective 3-The behavioral perspective 4-The psychodynamic perspective 5-The humanistic perspective 6-The socio-cultural perspective
The biological perspective
View human as :
complex animals
and focus on:
genetic and physiological influances on behavior
in which mental events are seen as the outcome of physiological processes.
according the the biological perspective mental events are seen as the outcome of what ?
mental events are seen as the outcome of physiological processes and genetic
The cognative perspective
Views humans:
as rational information processor and problem solvers whose higher mental processes allow them to think, judge, imagine and plan
عقلاني, منطقيrational
The behavioral perspective
believe:
the role of external environment and learning in behavior
scientist :
Watson and Skinner felt that control of the environment was the key to bringing about positive social and personal changes
The psychodynamic perspective
believe:
role of unconscious impulses, internal needs, conflicts and defence mechanisms in shaping of behavior.
scientist :
Freud
The humanistic perspective
believe :
role of self-actualization, freedom, and choice on behavior.
The socio-cultural perspective
believe :
role of social factors, values, beliefs, traditions cultural learning on behavior.
which perspective deals with the role unconscious mind ?
The psychodynamic perspective
Freud emphasize the role of unconscious impulses, internal needs, conflicts and defence mechanisms in shaping of behavior
which perspective deals with the role self-actualization and the freedom?
The humanistic perspective
Emphasize the role of self-actualization, freedom, and choice on behavior
which perspective deals with the role environment ?
The behavioral perspective
Behaviorists emphasize the role of external environment and learning in behavior.
Watson and Skinner felt that control of the environment was the key to bringing about positive social and personal changes
which perspective deals with the role traditions ?
The socio-cultural perspective
Emphasize the role of social factors, values, beliefs, traditions cultural learning on behavior
which perspective deals with the idea that human as problem solver ?
The cognative perspective
Views humans as rational information processor and problem solvers whose higher mental processes allow them to think, judge, imagine and plan.
which perspective deals with the role of the genetic and physiological processes?
The biological perspective
View human as complex animals and focus on genetic and physiological influances on behavior, in which mental events are seen as the outcome of physiological processes.
———— combines with —————–to determine our behavior
Genetic endowment combines with environmental factors to determine our behavior
-favorable or unfavorable environmental conditions can affect the geneticaly inherited potential of an organism
Genotype is
Genotype is specific genetic make up of the individual ,e.g Klinefelter syndrome genotype are XXXY,XXYY,XXXXY,XXY
Phenotype are
Phenotype are the observable characteristics of individual produced by that genetic endowment.
Heritability is
Heritability is proportion of variance attributable to genetic effects.
heritability coefficient means
heritability coefficient means :
The extent to which the degree of variation among a group of people in particular characteristic can be attributed to genetic factors
It applied :
only to differences within groups not to the contribution of genetic factors to any individual within that group
what’re Behavior genetic techniques to estimate the heritability coefficient ?
A-Epidemiological studies
B-The molecular genetic studies
Epidemiological studies of the behavior include ..
1-Family studies
2-Adoption studies
3-Twin studies
Family studies
- An individual’s first –degree relatives (parents , sibling, and children) share on average 50% of his genes,
- second- degree relatives (Grandfather, Aunt ,Nephew, Cousin) share on average 25% of his genes
- Shared environment can also be a powerful source of resemblance between relatives ,especially for behavioural traits
Adoption studies
In which a person who was adopted early in life is compared on some characteristics with both the biological parents and with the adoptive parents.
- If the adopted person is more similar to the biological parents than to the adoptive parents , genetic influence is suggested.
- If greatest similarity is shown with the adoptive parents , environmental factors are probably more important.
Seymour kety in 1978 found that 12% of biological family members of adopted schizophrenic patients has also been diagnosed with schizophrenia compared with a concordance rate of only 3% of adoptive family members suggesting a hereditary link.
what’s Seymour kety found
Seymour kety in 1978 found that 12% of biological family members of adopted schizophrenic patients has also been diagnosed with schizophrenia compared with a concordance rate of only 3% of adoptive family members suggesting a hereditary link.
Twin studies
If the identical twins are far more similar to one anather than are the fraternal twins, a genetic factor is likely to be involved.
The concordance rate for schizophrenia among monozygotic twins of schizophrenia is 50% compared with 10 – 12% among dizygotic twins.
It is always possible because identical twins are more similar to one anather in appearance they are treated more alike and therfore share more similar environment. To rule out this environmental explanation for greater psychological similarity is by compare set of identical twins who were separated very early in life and raised in different environment.
Many psychological characteristics including intelligence, persoality trait and certain psychiatric disorders have anoteable genetic contribution.
The correlation coefficients for identical twins on the trait of neuroticism and is almost as greater when they are reared in different environments as when they are reared together
The concordance rate for schizophrenia among monozygotic twins
50%
The concordance rate for schizophrenia among dizygotic twins.
10 – 12%
why the best study is the twin study ?
because identical twins are more similar to one anather in appearance they are treated more alike and therfore share more similar environment. To rule out this environmental explanation for greater psychological similarity is by compare set of identical twins who were separated very early in life and raised in different environment.
Many psychological characteristics including intelligence, persoality trait and certain psychiatric disorders have anoteable genetic contribution.
The correlation coefficients for identical twins on the trait of neuroticism and is almost as————when they are reared in different environments as when they are reared together
The correlation coefficients for identical twins on the trait of neuroticism and is almost as greater when they are reared in different environments as when they are reared together
The environmental factors interact with genetic …explain?
-for example one adoption study found that a low incidence of criminal behavior was found in the sons
whose biological fathers had no criminal records.
In contrast the criminal behavior of sons whose biological father had criminal records was very high even if their adoptive fathers had no criminal records
This pattern piont to ———-a genetic component in criminality
-The level of criminality was highest for all of those sons whose both biological and adoptive fathers had criminal records, suggesting a combined impact of genetic and environmental factors
The aim of the molecular genetic studies is to
identify the genes explaining the inheritance of a phenotype.
The molecular genetic studies include
1-The genetic linkage studies
2-The genetic association studies
The genetic linkage studies
If a particular locus of chromosome consistently segregates with the disease then that locus is likely to contain the gene,
example :
the identification of amyloid precursor protein(APP) gene locus on chromosome 21 in familial Alzheimer’s disease.
The genetic association studies
The genetic association studies is based on existence of polymorphism and measurment of its frequency in group of people who have the phenotype of interest and compare it with the control group,
example:
APOE4 association with Alzheimer’s disease
Apolipoprotein E
Patterns of inheritance
1-Autosomal Dominant
2-Autosomal recessive
3- X-linked recessive
4-X-linked dominant
Autosomal Dominant
1-The phenotypic trait is present in all indivituals carrying the dominant allele
2-males and females are affected.
3-male to male transmission can take place
4-transmission is not solely dependent on parental consanguineous matings انتقال لا يعتمد فقط على التزاوج الأقارب الوالدين
5-if one parent is homozygous for the abnormal dominant allele, all the members of F1 will manifest the abnormal phenotypic trait
6-half the offspring of an affected heterozygote will exhibit the abnormal trait
E.g Huntingtons disease ,Neurofibromatosis ,Sturge Weber syndrome
Autosomal recessive
1-hetrozygous individuals are generally carriers who do not manifest the abnormal phenotypic trait
2-the rarer the disorder, the more likely it is that the parents are consanguineous والأرجح أن الوالدين الأقارب
3-the disorder tend to miss generations but the affected individuals in family tend to be found among siblings
E.gTay- Sach disease
X-linked recessive
1-all male offspring manifest the abnormal phenotypic trait
2-male –to-male transmission does not take place-all of the daughters of an affected male will be carriers
3-female hetrozygotes are carriers; affected females are rare.
E.g Fragile X syndrome, Hunter syndrome, Cerebellar ataxia.
X-linked dominant
1-if an affected male mates with an unaffected female ,all the daughters and none of the sons are affected
2-if an unaffected male mates with an affected heterozygous female ,half the daughters and half the sons are affected
3-male –to –male transmission does not take place.
E.G Rett syndrome
Autosomal Dominant example
Huntingtons disease ,Neurofibromatosis ,Sturge Weber syndrome
Autosomal recessive example
Tay- Sach disease
X-linked dominant example
Rett syndrome
X-linked recessive example
Fragile X syndrome, Hunter syndrome, Cerebellar ataxia.
Premises of neurogenetics
مباني الوراثة العصبية
Specific genetic basis will emerge for certain psychiatric disorders.
- Schizophrenia
- Bipolar l disorder and Major depressive disorder
- Tourettes disorder
Schizophrenia
%general population = 1%
first degree relatives is = 10-12%
Second degree relatives= 5-6%
Child of two schizophrenic parents=40%
Dizygotic twin 12-15%,Monozygotic twin =45-50%
Heritability of schizophrenia = 80%
Schizophrenia Heritability
80%
Schizophreniafirst degree relatives
10-12%
Schizophrenia Second degree relatives
5-6%
SchizophreniaChild of two schizophrenic parents
40%
Schizophrenia Dizygotic twin
12-15%
Schizophrenia Monozygotic twin
45-50%
Bipolar l disorder and Major depressive disorder
first degree relatives
8-18 times more in the first degree relatives
Bipolar l disorder and Major depressive disorder
monozygotic twins.
33-90%
Tourettes disorder the mode of transmission
is autosomal dominant
Tourettes disorder percentage in male and female ?
of 99% in males and 70% in females
- 10% only of patients do not have an affected family member
- 90% of patients have a family history of the disorder.
