In the age of molecular genetics, meanwhile, the classical twin study design is only one aspect of genetics research. Twin studies estimate the heritability of a trait, but
molecular genetics attempts to pinpoint the effects of a particular gene.
Why is it important to genetic researchers to study twins?
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
.
How do genetics influence twins?
Genetics can definitely play a role in having fraternal twins. … However, for a given pregnancy, only the mother's genetics matter. Fraternal twins happen when
two eggs are simultaneously fertilized instead
of just one. A father's genes can't make a woman release two eggs.
What role does genetics play in twin intelligence studies?
Many of these studies have focused on
similarities and differences in IQ within
families, particularly looking at adopted children and twins. These studies suggest that genetic factors underlie about 50 percent of the difference in intelligence among individuals.
Why do psychologists use twin studies and adoption studies for research in genetics?
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.
Do twins come from Mom or Dad?
For a given pregnancy, the odds of conceiving fraternal twins are only determined by the mother's genetics,
not the father's
. Fraternal twins happen when two eggs are simultaneously fertilised instead of just one.
Who carries the twin gene?
While
men can
carry the gene and pass it on to their daughters, a family history of twins doesn't make them any more likely to have twins themselves. 3 But, if a father passes on the “twin gene” to his daughter, then she may have a higher chance than normal of having fraternal twins.
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. …
What do twin studies reveal about intelligence?
Twin studies have revealed that
intelligence has a strong genetic influence
.
What are the disadvantages 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.
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.”
Why are studies of identical twins raised in different environments extremely valuable?
Why are studies of identical twins raised in different environments extremely valuable in understanding the causes of a disease? They are extremely valuable in understanding the causes of a disease, because it
differentiates
between nature vs. nurture.
Why are twin studies flawed?
Twin studies make the
unjustified assumption that twins share the same prenatal environment
. … Thus, one cannot conclude that if identical twins are more similar in some behavior than fraternal twins, the increased similarity must be caused by the genes they share.
Who is more likely to have twins?
According to the Office on Women's Health,
women who are aged 30 years or older
are more likely to conceive twins. The reason for this is that women of this age are more likely than younger women to release more than one egg during their reproductive cycle.
Can you have twins if they don't run in the family?
Everyone has the same chance of having identical twins: about 1 in 250.
Identical twins do not run in families
. But there are some factors that make having non-identical twins more likely: non-identical twins are more common in some ethnic groups, with the highest rate among Nigerians and the lowest among Japanese.
Which parent determines identical twins?
This is why fraternal twins run in families. However, only women ovulate. So,
the mother's genes control
this and the fathers don't. This is why having a background of twins in the family matters only if it is on the mother's side.
