With so many twins among us these days,
it’s high time we celebrate some of the
most interesting facts about them.
1. Identical twins do not have
identical fingerprints.
You might think that because identical
twins supposedly share almost the same
DNA, they must also have identical
fingerprints. Well, that’s not true.
Fingerprints are not solely generated
based on DNA. When identical twins are
conceived, they start out with the same
fingerprints, but during weeks six
through 13 of pregnancy, as the babies
start to move, they each touch the
amniotic sac, and unique ridges and
lines are formed on each twin’s hand
that result in different fingerprints.
2. Massachusetts has the most twin
births of any state in America.
At nearly 4.5 for every 100 live births,
Massachusetts has the highest rate of
twin births. Connecticut and New Jersey
follow with 4.2 twins per every 100
births. Researchers hypothesize that
more multiple births occur in “affluent
towns outside of Boston” because of a
higher concentration of wealthier women
who have pursued careers. These women
are more likely to attempt to have
children at a later age and seek
reproductive assistance. The state with
the lowest rate of twin births is New
Mexico.
3. Mirror image identical twins have
reverse asymmetric features.
About 25 percent of identical twins
develop directly facing each other,
meaning they become exact reflections
of one another — they may be right and
left handed, have the same birthmarks
on opposite sides of their bodies or have
the same hair whorls that swirl in
opposite directions. This occurs when the
twins split from one fertilized egg more
than a week after conception.
4. Identical twins do not always have
the same genetics.
While identical twins derive from one
fertilized egg that contains a single set
of genetic instructions, also known as a
genome, it’s still possible for identical
twins to have serious differences in their
genetic makeup. Geneticist Carl Bruder
of the University of Alabama at
Birmingham closely studied the genomes
of 19 sets of adult identical twins and
found that in some sets, one twin’s DNA
differed in the number of copies of each
gene it had. Normally, every person
carries two copies of every gene, one
inherited from each parent, but Bruder
explains that there are “regions in the
genome that deviate from that two-copy
rule, [and] these regions can carry
anywhere from zero to 14 copies of a
gene.”
5. Mothers of twins may live longer.
A study published in the journal
Proceedings of the Royal Society B
focused on the population of women in
1800s Utah and found that women who
gave birth to twins were very strong and
healthy to begin with, so were likely to
live long lives. AsLiveScience writer
Stephanie Pappas explains it, “Twins
could be an evolutionary adaption in
which healthy moms take the chance to
pass on double their genes at once.”
However, because the data only includes
women who conceived twins naturally —
IVF was obviously not used in the 1800s
— the findings are not definitive.
6. Tall women are more likely to have
twins.
Gary Steinman, MD, PhD, an attending
physician at Long Island Jewish (LIJ)
Medical Center, discovered that taller
women have more insulin-like growth
factor (IGF), a protein that is released
from the liver in response to a growth
hormone that stimulates growth in the
shaft of longer bones. Having higher
levels of IGF results in increased
sensitivity of the ovaries, thus
increasing a woman’s chance of
ovulating. According to Steinman, the
more IGF a woman has, the greater
chance she has of becoming pregnant
with twins, because IGF “govern[s] the
rate of spontaneous twinning.”
7. Also, women who eat a lot of dairy
are more prone to conceiving twins.
Another study done by Steinman and
published in the Journal of Reproductive
Medicine found that women who eat
more dairy products may increase their
chances of conceiving twins. Steinman
tested this by comparing twin rates from
vegan mothers and non-vegan mothers.
Those who consumed dairy were five
times more likely to have twins. This is
because cows, like humans, also produce
IGF in response to growth hormone and
release it into their blood. Then it gets
released into their milk, which women
consume.
8. It’s possible that twins can have
different dads.
In 2009, Mia Washington gave birth to
twins who have different fathers – which
is said to be a one-in-a-million
occurrence. Dr. Hilda Hutcherson,
Clinical Professor of Obstetrics and
Gynecology at Columbia University,
explained to “Today” how it happened:
Normally, a woman releases one egg each
month. For Washington, there were two.
At the same time, the mom had
intercourse with two different men in
the span of five days. Because sperm
can remain alive in the reproductive
tract for that long, each man’s sperm
fertilized one of eggs. Voila! Two babies,
two dads.
9. Twins interact with each other in
the womb.
In 2011, researchers at Umberto
Castiello of the University of Padova in
Italy studied 3D videos of twins in their
mother’s womb. At 14 weeks of gestation,
twins were seen reaching for each other.
By 18 weeks, they touched each other
more often than they touched their own
bodies. The researchers said that
kinematic analyses of the recordings
revealed that the twins made distinct
gestures toward each other and were as
gentle to the other twin’s delicate eye
area as they were when they touched
their own.
10. Some conjoined twins can feel
and taste what the other one does.
Susan Dominus wrote a piece for The New
York Times about two conjoined twins,
Krista and Tatiana Hogan, who are
attached at the head through a
“thalamic bridge,”part of the brain that
acts as a sort of “neural switchboard”
and filters most sensory input. Scientists
have hypothesized that this connection
could result in one Hogan sister being
able to taste and feel what the other
twin is experiencing and to understand
each other’s thoughts. Dominus, who
spent a considerable amount of time
with the twins for her story, recorded
these amazing observations:
“[Their parents noticed] when one
girl’s vision was angled away from
the television, she was laughing at
the images flashing in front of her
sister’s eyes. The sensory exchange,
[researchers] believe, extends to the
girls’ taste buds: Krista likes ketchup,
and Tatiana does not, something the
family discovered when Tatiana tried
to scrape the condiment off her own
tongue, even when she was not
eating it.”
11. Forty percent of twins invent
their own languages.
These languages are called autonomous
languages. Researchers suspect that twin
babies use each other as models in
developing language when an adult
model language is frequently absent. The
“language” consists of inverted words
and onomatopoeic expressions. These
autonomous languages are formed when
two very close babies are learning how to
speak a real language alongside one
another and naturally often play and
communicate with each other. While this
is more common among twins, since they
are more likely to be around each other
and developing at the same rate, this
phenomenon can also sporadically occur
between two babies who are not twins.
The made up “languages” often
disappear soon after childhood, once
the children have learned a real
language.
it’s high time we celebrate some of the
most interesting facts about them.
1. Identical twins do not have
identical fingerprints.
You might think that because identical
twins supposedly share almost the same
DNA, they must also have identical
fingerprints. Well, that’s not true.
Fingerprints are not solely generated
based on DNA. When identical twins are
conceived, they start out with the same
fingerprints, but during weeks six
through 13 of pregnancy, as the babies
start to move, they each touch the
amniotic sac, and unique ridges and
lines are formed on each twin’s hand
that result in different fingerprints.
2. Massachusetts has the most twin
births of any state in America.
At nearly 4.5 for every 100 live births,
Massachusetts has the highest rate of
twin births. Connecticut and New Jersey
follow with 4.2 twins per every 100
births. Researchers hypothesize that
more multiple births occur in “affluent
towns outside of Boston” because of a
higher concentration of wealthier women
who have pursued careers. These women
are more likely to attempt to have
children at a later age and seek
reproductive assistance. The state with
the lowest rate of twin births is New
Mexico.
3. Mirror image identical twins have
reverse asymmetric features.
About 25 percent of identical twins
develop directly facing each other,
meaning they become exact reflections
of one another — they may be right and
left handed, have the same birthmarks
on opposite sides of their bodies or have
the same hair whorls that swirl in
opposite directions. This occurs when the
twins split from one fertilized egg more
than a week after conception.
4. Identical twins do not always have
the same genetics.
While identical twins derive from one
fertilized egg that contains a single set
of genetic instructions, also known as a
genome, it’s still possible for identical
twins to have serious differences in their
genetic makeup. Geneticist Carl Bruder
of the University of Alabama at
Birmingham closely studied the genomes
of 19 sets of adult identical twins and
found that in some sets, one twin’s DNA
differed in the number of copies of each
gene it had. Normally, every person
carries two copies of every gene, one
inherited from each parent, but Bruder
explains that there are “regions in the
genome that deviate from that two-copy
rule, [and] these regions can carry
anywhere from zero to 14 copies of a
gene.”
5. Mothers of twins may live longer.
A study published in the journal
Proceedings of the Royal Society B
focused on the population of women in
1800s Utah and found that women who
gave birth to twins were very strong and
healthy to begin with, so were likely to
live long lives. AsLiveScience writer
Stephanie Pappas explains it, “Twins
could be an evolutionary adaption in
which healthy moms take the chance to
pass on double their genes at once.”
However, because the data only includes
women who conceived twins naturally —
IVF was obviously not used in the 1800s
— the findings are not definitive.
6. Tall women are more likely to have
twins.
Gary Steinman, MD, PhD, an attending
physician at Long Island Jewish (LIJ)
Medical Center, discovered that taller
women have more insulin-like growth
factor (IGF), a protein that is released
from the liver in response to a growth
hormone that stimulates growth in the
shaft of longer bones. Having higher
levels of IGF results in increased
sensitivity of the ovaries, thus
increasing a woman’s chance of
ovulating. According to Steinman, the
more IGF a woman has, the greater
chance she has of becoming pregnant
with twins, because IGF “govern[s] the
rate of spontaneous twinning.”
7. Also, women who eat a lot of dairy
are more prone to conceiving twins.
Another study done by Steinman and
published in the Journal of Reproductive
Medicine found that women who eat
more dairy products may increase their
chances of conceiving twins. Steinman
tested this by comparing twin rates from
vegan mothers and non-vegan mothers.
Those who consumed dairy were five
times more likely to have twins. This is
because cows, like humans, also produce
IGF in response to growth hormone and
release it into their blood. Then it gets
released into their milk, which women
consume.
8. It’s possible that twins can have
different dads.
In 2009, Mia Washington gave birth to
twins who have different fathers – which
is said to be a one-in-a-million
occurrence. Dr. Hilda Hutcherson,
Clinical Professor of Obstetrics and
Gynecology at Columbia University,
explained to “Today” how it happened:
Normally, a woman releases one egg each
month. For Washington, there were two.
At the same time, the mom had
intercourse with two different men in
the span of five days. Because sperm
can remain alive in the reproductive
tract for that long, each man’s sperm
fertilized one of eggs. Voila! Two babies,
two dads.
9. Twins interact with each other in
the womb.
In 2011, researchers at Umberto
Castiello of the University of Padova in
Italy studied 3D videos of twins in their
mother’s womb. At 14 weeks of gestation,
twins were seen reaching for each other.
By 18 weeks, they touched each other
more often than they touched their own
bodies. The researchers said that
kinematic analyses of the recordings
revealed that the twins made distinct
gestures toward each other and were as
gentle to the other twin’s delicate eye
area as they were when they touched
their own.
10. Some conjoined twins can feel
and taste what the other one does.
Susan Dominus wrote a piece for The New
York Times about two conjoined twins,
Krista and Tatiana Hogan, who are
attached at the head through a
“thalamic bridge,”part of the brain that
acts as a sort of “neural switchboard”
and filters most sensory input. Scientists
have hypothesized that this connection
could result in one Hogan sister being
able to taste and feel what the other
twin is experiencing and to understand
each other’s thoughts. Dominus, who
spent a considerable amount of time
with the twins for her story, recorded
these amazing observations:
“[Their parents noticed] when one
girl’s vision was angled away from
the television, she was laughing at
the images flashing in front of her
sister’s eyes. The sensory exchange,
[researchers] believe, extends to the
girls’ taste buds: Krista likes ketchup,
and Tatiana does not, something the
family discovered when Tatiana tried
to scrape the condiment off her own
tongue, even when she was not
eating it.”
11. Forty percent of twins invent
their own languages.
These languages are called autonomous
languages. Researchers suspect that twin
babies use each other as models in
developing language when an adult
model language is frequently absent. The
“language” consists of inverted words
and onomatopoeic expressions. These
autonomous languages are formed when
two very close babies are learning how to
speak a real language alongside one
another and naturally often play and
communicate with each other. While this
is more common among twins, since they
are more likely to be around each other
and developing at the same rate, this
phenomenon can also sporadically occur
between two babies who are not twins.
The made up “languages” often
disappear soon after childhood, once
the children have learned a real
language.
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