PSYB30H3 Chapter Notes - Chapter 6: Heritability, Phenotype, Mendelian Inheritance

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Published on 20 Apr 2013
School
UTSC
Department
Psychology
Course
PSYB30H3
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of 3
Genetics Chapter 6
Genotypes- The way our genes interact to affect our personalities
Behavioural Genetics- The study of genetic and environmental contributions to individual differences in
personality and behaviour.
Genotype environmental correlation- What if people change environment and environment change
people
Phenotype- genotype + environment + gene-environmental correlation + gene-environmental
interaction
Heritability- The amount of observed individual differences in some characteristic that can be
accounted for genetic differences. It describes the difference among populations. Estimates for ethnic
groups because it varies across ethnic groups.
Environmentality- Estimates the extent to which observed individual differences can be traced in
anyway to individual differences in environments
Environmentality, heritability and measurement error account for all the characteristics of people.
Heritability for height is very good to judge in developed countries because their environment is the
same and people usually consume around the same amount of nutrition
Shared environment- Aspects of family environment that are usually the same for all children living in
the household.
Nonshared environment- Experiences that relatives have that make them different from each other.
Children growing up in the same family are no more alike than those growing up in different families.
MZA twins- Identical twins that are raised apart, this is good to tell if there is a difference between
heritability and environmental components
The double the difference method- Assumes that twins were reared under the same environment.
Assumption of representativeness, twins re not representative of the population when it comes to birth
rate and prematurity because they tend to weigh less and they are infrequently born.
Equal environments assumption- Pertains to similar treatment that is needed for the specific study.
The rmza method- Researchers assume that adopted families of each twin are different from each
other.
Selective placement- When the adopted families of each twin are similar it makes it impossible to see
the effects of genetics apart from environment because it joins the two.
Mza studies with adopted families- They usually assume that adopted families are like non adoptive
families but these types of families go through interviews to rule out criminal background, drug or
alcohol abuse or extreme poverty.
Heritability of personality traits range from 0.4 to 0.6
Alleles- Different forms of the same genes
Mendelian inheritance- Inheritance patterns where one trait dominates over another
Epigenetics- The study of genes and interaction with environment
Genes- A sequence of DNA with codes for a specific trait
Exons- the coding parts of genes
Introns- the non coding parts of genes
Positional cloning- Researchers finding harmful genes and then replacing them with positive genes
Dialectic- Proposed by the philosopher Hegel, it is a way of thinking in which contradictions are seen to
be part of a higher truth.
Genotype environment interaction- Occurs when a genotype responds differently to an environment .
People respond differently to the same environment because of their genetic makeup.
Genotype environment correlation- Occurs when a genotype is exposed differently to an environment.
When people with a particular genotype find themselves in an environment that either promotes that
genotype or decreases that genotype.
Selective serotonin reuptake inhibitors- Blocks the cells that process serotonin
Passive genotype environment correlation- When parents provide both the environment and genes
that is favourable to the development of those genes. Parents who re very intellectual genes providing
an environment for their kids to read.
Reactive genotype environment correlation- The association between an individual’s genetically
influenced behaviour and others’ reactions to that behaviour.
Active genotype environment correlation- The association between an individual’s genetic dispositions
and the environmental spaces that individual selects. For example, individuals who are characteristically
extroverted may seek out very different social environments than those who are shy and withdrawn.
Positive genotype environment correlation- Conditions are favourable for developing a particular
characteristic.
Negative genotype environment correlation- People with high genetics values for a characteristic find
themselves in a low environment that is not conducive to that characteristic.
G Allele- Men with this did not encourage rule breaking and were more popular among the group

Document Summary

Genotypes- the way our genes interact to affect our personalities. Behavioural genetics- the study of genetic and environmental contributions to individual differences in personality and behaviour. Genotype environmental correlation- what if people change environment and environment change people. Phenotype- genotype + environment + gene-environmental correlation + gene-environmental interaction. Heritability- the amount of observed individual differences in some characteristic that can be accounted for genetic differences. Estimates for ethnic groups because it varies across ethnic groups. Environmentality- estimates the extent to which observed individual differences can be traced in anyway to individual differences in environments. Environmentality, heritability and measurement error account for all the characteristics of people. Heritability for height is very good to judge in developed countries because their environment is the same and people usually consume around the same amount of nutrition. Shared environment- aspects of family environment that are usually the same for all children living in the household.