How Does The Environment Affect Identical Twins?

Any differences between identical twins is expected to be due to environmental factors since

they are genetically identical

, whereas fraternal twins only share half of their genes on average. … When an environmental influence is dominant, the trait similarity would be the same for identical and fraternal twins.

How can the environment affect identical twins making them different?

Because identical twins share all of their genes,

their measurements of IQ and sleep time will be more similar the bigger role genes play in it

(i.e., differences between two identical twins must be caused by the environment because their genes are the same).

What factors influence identical twins?

Monozygotic twinning is generally felt to be independent of

race, genetic factors, maternal age, and parity

. Dizygotic twinning, in contrast, does appear to be influenced by race, genetics, parity, maternal age, fertility-enhancing drugs, folic acid supplementation, and maternal nutritional status.

Does the environment influence IQ in identical twins?

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

.

Do twins share the same environment?

Because

both fraternal and identical twins theoretically share the same environment

—the same family, the same home, and the same community—looking at the differences between identical and fraternal twins can tell us something about the effects of nature versus nurture on a number of factors.

How does environmental factors affect gene expression?

Environmental factors such as diet, temperature, oxygen levels, humidity, light cycles, and

the presence of mutagens

can all impact which of an animal's genes are expressed, which ultimately affects the animal's phenotype.

Do twins have the same IQ?

It was concluded, among many other things, that

identical twins are about 85 percent similar for IQ

, whereas fraternal twins are about 60 percent similar. This would seem to indicate that half of the variation in intelligence is due to genes.

How can I increase my chances of having identical twins?

Factors that increase the chance of twins include:

consuming high amounts of dairy foods

, being over the age of 30, and conceiving while breastfeeding. Many fertility drugs including Clomid, Gonal-F, and Follistim also increase the odds of a twin pregnancy.

Do twins have twins?

For instance, some people believe it's

unlikely that a twin will have twins

, but they may be more likely to have twin grandchildren.

What gender is most common in identical twins?

In the US, 105 non-twin males are born for each 100 non-twin females. However, males are slightly more likely than females to die in the womb. And because the death rate in the womb is higher for twins than for singleton births,

female twins

are more common than male twins.

Why are my identical twins so different?

If by chance one identical twin ‘silences'

the X chromosome that

came from Dad's sperm and the other twin silences the X chromosome that came from Mum's egg, then they have different genes working in their systems, which can result in noticeable differences.

What are the flaws with twin studies?

Put another way, twin studies

fail to separate the effects of genes and the prenatal environment

. This failure casts doubt on claims of the relative effects of genes and environment on intelligence, psychiatric disorders, personality and other psychological variables, and other conditions.

Is IQ more genetic or environmental?

Numerous studies on twins suggest that between 40 and 80 percent of the variance in IQ is linked to

genetics

, suggesting that genetics may play a larger role than environmental factors in determining an individual's IQ.

Why do identical twins have no fingerprints?

Identical twins do not have identical fingerprints, even

though their identical genes give them very similar patterns

. … Small differences in the womb environment conspire to give each twin different, but similar, fingerprints. In fact, each finger has a slightly different pattern, even for your own fingers.

What Do identical twins have in common?

Identical twins are also known as monozygotic twins. They result from the fertilization of a single egg that splits in two. Identical twins

share all of their genes and are always of the same sex

. In contrast, fraternal, or dizygotic, twins result from the fertilization of two separate eggs during the same pregnancy.

Do identical twins look identical?

After all, while huge differences can and do happen with fraternal twins,

identical twins are usually exactly that — identical in skin, hair and eye color

. But, actually, twins who start out with identical DNA always have slightly different DNA by the time they're born.

Does environment affect genotype?

Genotype generally remains constant from one environment to another

, although occasional spontaneous mutations may occur which cause it to change. However, when the same genotype is subjected to different environments, it can produce a wide range of phenotypes.

Are identical twins 100% the same?

Identical twins form from the same egg and get the same genetic material from their parents — but that doesn't mean they're genetically identical by the time they're born.

What are three environmental factors that can alter gene expression?

Environmental factors such as

food, drugs, or exposure to toxins

can cause epigenetic changes by altering the way molecules bind to DNA or changing the structure of proteins that DNA wraps around.

Can your environment change your genes?

Epigenetics

is the study of how your behaviors and environment can cause changes that affect the way your genes work. Unlike genetic changes, epigenetic changes are reversible and do not change your DNA sequence, but they can change how your body reads a DNA sequence.

Do identical twins have the same eyes?

A study published in the journal Investigative Ophthalmology and Visual Science finds that the identical genetic code of identical twins means that

they have identical eyes

, even down to the smallest details. Share on Pinterest A new twin study finds that tiny optical changes are heavily influenced by genetics.

What country has the most identical twins?

Are twins probable?

It is estimated that

1 in 250 natural pregnancies will naturally

result in twins. While twin pregnancies can happen by chance, there are some factors that may increase your odds of having two babies at the same time. Let's learn about twins!

At what point does an egg split into twins?

Zygotic splitting occurs

between days two and six when the zygote divides

, usually into two, and each zygote then goes on to develop into an embryo, leading to identical twins (or triplets if it divides into three). These are known as “monozygotic” twins (or triplets).

Can I have twins if my husband is a twin?

If the twins are present on your husband's/partner's side, it won't influence your chances of having twins

. Remember, the gene for hyperovulation is only a factor for the mother. If your mother (or your grandmother or aunt) was or had fraternal twins, you might have the gene.

Can a twin have triplets?

It is possible to have triplets

where two of the babies are identical twins (and may share one placenta, and even one sac) and the third baby is non-identical (with completely separate placenta and sac).

Do twins have same blood type?

Monozygotic (identical) twins will have the same blood type

, with a few very rare exceptions. Dizygotic (fraternal) twins may have the same blood type, or they may have different types.

Are twins less intelligent?

In both surveys, twins scored about 5 IQ points (one third of a standard deviation)

lower than singletons

. … This is supported by a Dutch study of adult twins, which found no significant difference in IQ between singletons and twins from the same families.

Are identical twins a fluke?

Fraternal twins run in families.

Identical twins are a fluke of nature

. There are 7 different types of twins: identical, fraternal, half-identical, mirror image twins, mixed chromosome twins, superfecundation, and superfetation.

What are the rarest type of twins?

Monoamniotic-monochorionic Twins

This is the rarest type of twin, and it means a riskier pregnancy as the babies can get tangled in their own umbilical cords.

What parent carries the twin gene?

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.

What does a child inherit from their father?

As we've learned, dads contribute one Y or one X chromosome to their offspring. Girls get two X chromosomes, one from Mom and one from Dad. This means that your daughter will inherit

X-linked genes

from her father as well as her mother.

Which is more influential heredity or environment?

The environment

is most influential because it moulds a child in its characteristics. This therefore become the child's personality.

Can a child have a higher IQ than parents?

But genetics can explain the wide range of possible IQs too because so many different genes are involved in developing and running a brain. It is possible, for example, to inherit all the higher IQ genes from each parent and leave the lower IQ ones behind. Now

the child will be brighter than the parent

.

Can one identical twin have Down syndrome?

European scientists explored the differing gene expression of identical twin fetuses with a rare distinction: One

was genetically normal

and the other had trisomy 21 — the third copy of chromosome 21 that produces Down syndrome.

Do twins have emotional problems?

Parents' reported proportions of probable behavioural/emotional disorders did not differ between the twin and singleton girls, but among the twin boys there was a nonsignificant trend of being more often probably disturbed. Twins were reported to be

less disturbed

than singletons according to the teachers' assessments.

What are the shortcomings of twin studies what can't they prove?

The twin method, they say,

underestimates the influence of environment and cannot prove that genes actually cause a particular behavior

. While the studies assume that twins go randomly into different households, adoption agencies tend to place them with families not unlike their own, critics say.

What value do twin studies have to psychology?

Twins provide

a valuable source of information

for health and psychological research, as their unique relationship allows researchers to pull apart and examine genetic and environmental influences. Twin study findings have been influential in detecting and treating various diseases and psychological disorders.

Can twins be of different genders?

Fraternal twins may be of the same or different sexes

. They share half of their genes just like any other siblings. In contrast, twins that result from the fertilization of a single egg that then splits in two are called monozygotic, or identical, twins.

Do mothers of twins live longer?

They found that compared with mothers of singleton births:

Mothers of twins lived longer after menopause

. For women born before 1870, their annual risk of dying after age 50 was a statistically significant 7.6 percent lower than for moms of singletons.

What are mirror twins?

The term mirror twin is used to describe

a type of identical, or monozygotic, twin pairing in which the twins are matched as if they're looking into a mirror

— with defining characteristics like birthmarks, dominant hands, or other features on opposite sides.