Modern twin studies have concluded that
almost all traits are in part influenced by genetic differences
, with some characteristics showing a stronger influence (e.g. height), others an intermediate level (e.g. personality traits) and some more complex heritabilities, with evidence for different genes affecting …
Why are twin studies important?
We study twins to understand how much of the difference in a trait between people is caused by genes and how much is caused by the environment. These studies are important because they
help scientists quantify genetic and modifiable environmental factors that increase the risk of certain diseases
.
What is the value of Twin Studies in learning about personality?
Twin studies allow
researchers to examine the overall role of genes in the development of a trait or disorder
. Comparisons between monozygotic (MZ or identical) twins and dizygotic (DZ or fraternal) twins are conducted to evaluate the degree of genetic and environmental influence on a specific trait.
What have we learned from twin studies?
Through studying twin pairs we identified the first gene that influences both mammographic density
(the amount of white areas on a mammogram) and risk of breast cancer
, called LSP1. His team found monozygotic (identical) twins were highly similar for mammographic density, which predicts future risk of breast cancer.
What is the logic of twin studies?
The simple yet elegant logic of the twin method derives from the
differences in genetic relatedness between the two types of twins
. Identical (monozygotic or MZ) twins share 100 percent of their genes, while fraternal (dizygotic or DZ) share 50 percent of their genes, on average.
What are the disadvantages of twin studies?
Limitations of twin studies
Results from twin studies
cannot be directly generalized to the general population
, due to lack of randomization; in addition, they are different with regard to their developmental environment, as two fetuses growing simultaneously.
What problems are there with twin studies?
The most common objections to twin studies have been: (1)
Twins have almost always been reared to- gether
and this common rearing may have con- tributed to increased concordance in monozygotic (MZ) twins because of psychological characteris- tics unique to such pairs (8, 29);
Why are twin studies unethical?
The study, which has since been criticized for being unethical — for example, neither the children's biological parents nor the adopting families were informed — was an attempt to get at the central psychological questions of “nature versus nurture” and the “twinning reaction.”
Do twins have the same fingerprints?
Even identical twins – who have the same DNA sequence and tend to share a very similar appearance –
have slightly different fingerprints
. That's because fingerprints are influenced by both genetic and environmental factors during development in the womb. … But fingerprints are not unique to humans.
Why are twin and adoption studies important?
Twin and adoption studies can be
used to separate the effects of genetics from the social environment of rearing
, and twin studies can often give clues to the importance of biological environmental factors.
Are twin studies reliable?
Although the authors of psychiatry and psychology textbooks and other mainstream publications usually endorse genetic interpretations of psychiatric twin studies uncritically, there is a fatal flaw underlying these studies: identical twin pairs grow up experiencing much more similar environments than experienced by …
Why are twin studies important quizlet?
Twin studies are
almost the only way to separate out the effects of nurture and nature
, as twins share 100% of their genes so if it is due to nature they should both be affected by the characteristic. This makes it the most useful way to measure the involvement of genetics in disorders.
How do twin studies support the view that intelligence is inherited?
Genes
have a very strong influence over how certain parts of our brains develop
, scientists in the US and Finland have found. In identical twins, these areas showed a 95 to 100 per cent correlation between one twin and the other – they were essentially the same. …
Is schizophrenia more common in twins?
Previous studies show that
schizophrenia affects both members of identical twins in 41% to 61% of cases
, but only 0 to 28% in non-identical twins. A previous pooling of twin studies has suggested that the “heritability” of schizophrenia is 81%.
What is twin method?
The twin method consists of
a formal comparison between the resemblance between identical
(monozygotic, MZ) twins and the resemblance between fraternal (dizygotic, DZ) twins for some trait of interest.
Are Temperments genetic?
Scientists estimate that
20 to 60 percent of temperament is determined by genetics
. Temperament, however, does not have a clear pattern of inheritance and there are not specific genes that confer specific temperamental traits.
