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National Geographic In The Womb Identical Twins — Transcript

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0:01[Music]
0:10so here's your babies in
0:124D and as we can see they're
0:16[Music]
0:20identical twins are as close as nature
0:23gets to human
0:26cloning their identical genetic makeup
0:29is one of the wonders of human
0:33reproduction the close similarities can
0:38Astound even identicals separated at
0:41Birth often lead strikingly similar
0:43lives with the same jobs tastes and
0:51hobbies but identicals can also confound
0:57expectation advances in genetic science
1:00are revealing that identical twins are
1:02not as identical as we
1:08thought through state-of-the-art in the
1:11womb 4D Ultrasound
1:13scans scientifically accurate visual
1:16effects and specially short microscopy
1:19footage we will reveal the Hidden World
1:22of Twin fetal development
1:28[Music]
1:38[Music]
1:46in a world where most of us are
1:48individual identical twins capture the
1:54imagination but for scientists it's not
1:57their similarities that prove most
1:59fascinating
2:00but their
2:02differences they may not look it but
2:05these boys are identical twins born with
2:09dramatically different birth
2:14weights twins like these with major
2:18physiological differences present an
2:20enormous
2:21opportunity to reveal truths about human
2:27identity from fingerprints and
2:29intelligence to disease and even sexual
2:34[Music]
2:45orientation like
2:47everyone identical twins begin life as a
2:50single
2:52cell a fertilized egg called a zygo
2:58[Music]
3:01this cell contains 23 pairs of
3:04chromosomes tightly packed strings of
3:07genes one set from the mother's egg and
3:10one from the father's
3:12spone together they make up the entire
3:15genetic blueprint for a new human
3:19[Music]
3:27life a few hours after fertilizing ation
3:30the cell with its cargo of chromosomes
3:33embarks on a remarkable
3:36Journey it travels along the fallopian
3:39tube towards the
3:41womb the Single Cell now starts to
3:44divide first two then four then
3:49eight each cell an identical replica of
3:52the
3:54other this rapidly multiplying
3:56collection of cells is called a blast
3:58assist
4:00and it's here that Nature's most
4:02remarkable reproductive anomaly can
4:05sometimes
4:10occur very occasionally there is an
4:13event so mysterious that until recently
4:16it's never been
4:20witnessed several days after conception
4:23the Blas assist spontaneously splits
4:25into two
4:31each new blasty is composed of cells
4:34with the same identical set of
4:36chromosomes carrying the same
4:38arrangement of genes along their
4:40length the two blastic ists now have the
4:44potential to develop into identical
4:53twins exactly how and why the blastic is
4:56splits is one of reproductive Sciences
4:59greatest
5:01Mysteries but in 2007 during a
5:04laboratory study of 26 embryos
5:07embryologists witness this event for the
5:10first
5:12time the blasey's outer membrane is
5:15called the Zona peluca the lining inside
5:18is called the
5:20trophoblast just one cell layer thick
5:23the Tropa blast will eventually develop
5:25into the placenta
5:30within lies the Inner Cell Mass
5:33embryonic stem cells that will
5:35eventually become the
5:39fetus over the course of 4 days the
5:42embryologists noticed that a junction
5:45between a cell in the trophoblast
5:46membrane would regularly
5:49weaken letting liquid leak out and
5:52causing the Tropa blast to collapse like
5:55a balloon full of
5:57water then it would repair it
6:03itself but in two of the eggs the
6:05embryologists spotted something no one
6:08had ever seen
6:11before after the membrane collapsed the
6:14Inner Cell mass divided in
6:17two each Clump sticking to a different
6:20side of the trough blast as it
6:25reinflated if these clumps were to
6:27develop in uteru they would have
6:29eventually grow into identical
6:35twins born from the same single
6:38fertilized egg it's not surprising that
6:41most identicals retain a similar
6:43physical appearance as they grow up
6:46influence of genes reaches Beyond how we
6:49look genes also affect personality and
6:53taste making us flamboyant rather than
6:57shy with a taste for coffee instead of
7:00tea and a love of routine or desire for
7:06experimentation similarities between
7:08twins are often more than Skin
7:10[Music]
7:12Deep Dennis and David Herrera a
7:1653-year-old identical from
7:19California After High School both became
7:22officers for the Los Angeles Police
7:26Department because they were raised
7:28together and when went to the same
7:30school and had the same friends it's
7:32impossible to say whether their career
7:34choice was influenced by their gen or
7:36their
7:37[Music]
7:44upbringing to really test the extent to
7:46which our genes influence our life
7:49choices scientists study identicals who
7:52have been separated at Birth and raised
7:54in different environments
7:56[Music]
8:00Daphne and Barbara were separated as
8:02babies and had no contact with each
8:04other for 40
8:08years they were raised in very different
8:11families one by a scientist the other by
8:14a municipal
8:17guardner but the similarities between
8:20them are striking and perhaps Beyond
8:24coincidence they both left school at
8:2714 at 16 they both fell in
8:31love in their early 20s they each
8:34married their childhood
8:37sweethearts they both suffered
8:39miscarriages at the same age but went on
8:42to have children in their early
8:4520s both have an irrational fear of
8:48blood and of falling
8:53down when they met for the first time on
8:55a train platform they wore almost
8:58identical clothing
8:59[Music]
9:03the similarities are
9:05remarkable they suggest that genes play
9:08a powerful role in shaping many aspects
9:10of our lives and
9:12[Music]
9:15personalities but as we will see it's
9:17the differences between identicals that
9:19could offer science the greatest
9:22opportunity the chance to solve the
9:24age-old debate of nature versus nurture
9:28[Applause]
9:30when these twins were born in
9:322006 Jake weighed a healthy 2 and 1/2
9:35kilos his twin Tom weighed just over
9:39half a
9:40kilo since they're identicals this
9:43dramatic difference was a
9:46mystery for answers doctors look to the
9:50one environment the boys shared before
9:53birth the womb
9:58[Music]
10:01by day five the two identical blastic
10:04ists have reached the
10:05womb now they face one of the most
10:08critical events in their 9-month Odyssey
10:11one that could dramatically affect their
10:13Fortunes in the womb and
10:16[Music]
10:18Beyond when they were born Jake weighed
10:212 and 1/2 kilos and his brother Tom half
10:24a
10:27kilo and yet their identic
10:30born just minutes
10:35apart how could twins with the same
10:38genes look so
10:40[Music]
10:42different the answer May lie not in
10:44their
10:45DNA but in events that occurred in the
10:48environment they
10:49shared the
10:52womb and the first most critical event
10:56is implantation
10:58[Music]
11:05around day six the blast assy must
11:08implant in the wall of the womb securing
11:11its position for the next 250 days
11:15growth but timing is
11:19everything each twin will rely on a
11:22placenta to supply it with oxygen and
11:24nutrients but the placenta only starts
11:27to develop after implantation
11:30so blastic ists that split early before
11:32they implant each get their own placenta
11:36but those that split late after
11:39implantation must share
11:44one a shared placenta May mean one twin
11:49receives less nourishment than the other
11:51as a result it grows much more slowly a
11:55condition called selective intrauterine
11:57growth restriction
11:59[Music]
12:07there are even rare instances when
12:10identical twins have their own placentas
12:12and yet develop this condition
12:15identicals Jake and Tom are one such
12:18[Music]
12:22case their different weights are the
12:24result of events that occurred long
12:26before their born but their effect
12:29May last a
12:31[Music]
12:42lifetime once implantation has occurred
12:45embryonic development is surprisingly
12:47[Music]
12:50rapid by the end of the third week a
12:53rudimentary body shape is already
12:55emerging
12:58[Music]
13:02the embryo already resembles the
13:04beginnings of a body totally unprotected
13:07by skin and
13:09bone on one Edge stem cells flow over
13:13and are assigned their fate by the
13:16organizer one of the first organs to
13:18form is the heart until now just a clump
13:22of muscle
13:25cells then around day 22 a single cell
13:28in in this dormant clump of muscle cells
13:31spontaneously
13:37contracts it sets off a chain
13:39[Music]
13:43reaction one after the other neighboring
13:46cells begin to contract until the entire
13:49vessel is pulsating
13:58[Music]
14:05two tiny Hearts about the size of two
14:08pin heads beating
14:13[Music]
14:26together our twin embryos have
14:29approximately the same number of cells
14:31the same DNA and yet incredibly they may
14:35already be
14:40different is personality innate or learn
14:43over
14:44time why does some of us succumb to
14:47disease While others remain
14:49[Music]
14:51immune and from where do we get our skin
14:54color what makes one person gay another
14:58straight
15:01the answers are not as simple as we once
15:08thought Remy and Ken are fraternal
15:12[Music]
15:14twins the result of two separate sperm
15:17fertilizing two separate
15:23eggs the girl's parents are of mixed
15:27ancestry this usually means the children
15:29will also look mixed race but not
15:35always being mixed ancestry means
15:38carrying a mixed set of genes for both
15:40lighter and darker
15:42skin in Remy's case a sperm with a set
15:46of genes that produce darker skin
15:48children fertilized an egg with similar
15:53characteristics in kian's case a sperm
15:57with genes that create lighter skin
15:59children fertilized a similar egg
16:04too the result twins but twins who look
16:09very
16:11different Remy and Kian show us that
16:14twins can often confound
16:17expectation but they are not the only
16:20[Music]
16:22ones in 2001 a pair of twins were born
16:26who at first appeared to be a boy and
16:29go on closer inspection it became clear
16:33that one had signs of both male and
16:35female genitalia the twin was a
16:38hemaphrodite
16:40scientists believe that this happened
16:42because a single egg was fertilized by
16:44two
16:45sperm one with a female sex chromosome
16:49and one with a male sex chromosome the
16:52egg developed into a blast assist with
16:54both male and female cells
16:58[Music]
17:00the egg then divided and each of the two
17:03new cells shed an extra chromosome
17:06resulting in a blasy composed of both
17:08male and female
17:15cells that blasticus then split to
17:18create
17:19twins by chance one had more cells with
17:23the male sex chromosome and developed
17:25into a boy while the other had similar
17:28numbers of cells with male and female
17:30sex chromosomes resulting in a child
17:33with male and female
17:37genitalia it was a startling
17:40Discovery twins who are halfway between
17:43identical and fraternal the only known
17:46case of semi- identicals in the
17:49world the simple classifications we're
17:51used to are breaking down and will come
17:54to inform much of our newer
17:56understanding about how Twins and by
17:58extension all of us
18:02[Music]
18:06developed at 5 weeks our identical twin
18:10embryos are beginning to take
18:12[Music]
18:19shape now curved into a c-shape their
18:22heads and tails can be
18:26distinguished as can hearts
18:30spinal
18:31columns and the beginnings of tiny limb
18:36[Music]
18:39buds at this stage the embryo looks
18:43almost indistinguishable to any
18:45vertebrate in the animal
18:46[Music]
18:48kingdom these fragile creatures just 1
18:52and a half millim long are about to
18:54embark on a critical period of brain
18:56development
19:06this 5we Milestone could be another
19:08stage where identicals develop key
19:11differences before they're even
19:17born celso and Jesus are identical twins
19:21they were raised
19:23[Music]
19:26together as they grew up they remain
19:29physically similar but their tastes and
19:31interests began to
19:33diverge celso became interested in dance
19:36and Academia while Jesus preferred
19:40Sports the most surprising difference
19:43between the two brothers is that celso
19:46here wearing black is
19:51gay the differing sexual orientation of
19:54identical twins is an opportunity to
19:56investigate one of science's most
19:58controversial questions are people born
20:03[Music]
20:07gay as Selsa and Jesus were raised by
20:10the same parents in the same household
20:13they inevitably share the same
20:14environment at a crucial time in their
20:16personal
20:17[Music]
20:22development in the general population
20:25the chance of someone being gay is less
20:27than 5%
20:29unless you have a gay
20:32twin here the chances are much
20:35higher if you're fraternal sharing half
20:38your
20:39genes there's nearly a 25% chance that
20:42you will also be
20:47gay if you're identical sharing all your
20:50genes there's roughly a 50% chance that
20:53you will also be gay
20:57[Music]
20:59this suggests that there must be some
21:01genetic component to our
21:04[Music]
21:09sexuality however it can't be all down
21:12to genes otherwise all identicals would
21:15be either both gay or both
21:18straight some other Factor must be at
21:21Play
21:24[Music]
21:31in their first few weeks all fetuses
21:33develop along similar lines if nothing
21:37changed we would all be born
21:41female fetuses with the male Y
21:44chromosome will form testes at about
21:46week six that begin to produce the
21:48hormone
21:49testosterone but at about the 8th week
21:52testosterone is released and may affect
21:55early brain development
22:00this hormone masculinizes the body
22:03testosterone also masculinizes the brain
22:07including a part called the
22:09hypothalamus part of the network which
22:11controls who we find sexually
22:15attractive some scientists believe that
22:17the more the hypothalamus is exposed to
22:20testosterone the more it sets the stage
22:22for sexual inclination towards women
22:25[Music]
22:31occasionally a male fetus may not
22:33produce sufficient testosterone or its
22:36brain does not absorb enough to shape it
22:38along heterosexual
22:41lines if this theory is right then it
22:44may be that celso the gay brother
22:46absorbed enough testosterone to
22:48masculinize his body but not enough to
22:51fully differentiate his brain as a
22:54result he was left with a desire for men
22:59[Music]
23:05although there are still many Mysteries
23:07twins like these are playing a crucial
23:09role in informing scientists about how
23:12and when we all develop our
23:15[Music]
23:19sexuality by the eth week our identical
23:22twins have finished their embryonic
23:24stage of development and are now known
23:26as fetuses from the Latin meaning
23:32Offspring the twins now secure in their
23:35own Sachs but sharing a placenta have
23:39approximately 200 days left until
23:43birth now their growth
23:46[Music]
23:48accelerates by 13 weeks they're
23:51beginning to look more
23:53[Music]
23:56human the eyes of have moved
24:00together and the head is in better
24:02proportion to the rest of the
24:03[Music]
24:09body it's also the end of the first
24:12trimester the time most pregnant women
24:15will have their initial ultrasound
24:23scan the ultrasound sonographer checks
24:25for basic signs of normal development
24:29so here's your babies in 4D and as we
24:32can see they're
24:39identical the sonographer sees a single
24:42placenta a sure sign that the twins are
24:46identical you can see here a single
24:49prenter like a t- section which proves
24:51that you're having identical
24:53twins so when would you see them start
24:55interacting or reacting against each
24:57other we can see them almost sort of
25:03moving from now on the mother will be
25:06monitored
25:08closely twin pregnancies are more at
25:11risk of premature births immature
25:13development of lungs and organs can lead
25:16to
25:18complications these complications make
25:21natural childbirth more dangerous as a
25:24result twins are around 50% more likely
25:27to be born by C Ian section than
25:30[Music]
25:36Singleton the timing of the scan also
25:39marks the start of the second
25:41[Music]
25:44trimester the second trimester from 12
25:46to 24 weeks we'll see not only dramatic
25:49growth but massive development in
25:51everything from the structure of the
25:53brain to the refinement of facial
25:55features
26:00by the end of this stage the fetuses
26:02will be small but almost perfectly
26:05[Music]
26:11formed they look very similar but new
26:14research reveals that even at this early
26:16stage identical twins may already be
26:20less
26:22identical subtle changes are underway
26:25that will become greater throughout
26:27their lives
26:31and the mechanism responsible is one of
26:34the most complex yet fascinating
26:36processes in the whole of human
26:38[Music]
26:53development 15 weeks into their Journey
26:56from conception to birth our ident
26:58identical twins begin to move for the
27:00first
27:04time they start to interact exploring
27:08their environment with their hands and
27:10feet touching and even appearing to
27:19kiss their mother in later pregnancy
27:22will feel the same kicks each twin feels
27:24in uteru
27:28at times they appear aggressive at
27:31others almost
27:33caring they look
27:35identical but unseen influences may
27:38already be taking
27:40effect ones that could subtly alter the
27:43expression of genes in their growing
27:53body identical Jake and Tom are now aged
27:5617 months
28:00Jake is 8 cm taller than Tom and 4 kilos
28:08heavier when they were born in 2006
28:12doctors attributed these discrepan is in
28:14size and weight to restricted nutrition
28:17or blood flow in the
28:19womb they expected Tom to catch up but
28:23after a year and a half they're
28:25investigating whether Tom may be
28:27suffering from a genetic condition
28:29called Russell silver syndrome a growth
28:34disorder one of the causes of this
28:36syndrome may be a problem with a growth
28:38gene on chromosome
28:4211 scientists are puzzling over why Tom
28:45and his brother do not both have the
28:49syndrome identical twins after all have
28:52identical genes
28:56[Music]
29:00genetic puzzles like these are opening
29:03up a little known world at the outer
29:05reaches of science
29:11epigenetics this growing field of
29:13biology may help explain the differences
29:15between Twins like Tom and
29:18[Music]
29:21Jake epigenetics reveals that while
29:24their DNA code may be the same the way
29:27it fun funs can
29:30differ the human genome contains around
29:3325,000 genes each with its own specific
29:37function such as producing energy or
29:40directing cell
29:42division now geneticists are
29:44investigating a previously unknown
29:46aspect of the genome called the
29:50epigenome there is a series of chemicals
29:53that act as switches capable of
29:55activating or deactivating individual
29:59genes one of these switches works by a
30:02process called DNA
30:05methylation this causes enzymes inside a
30:08cell to attach a minuscule molecular
30:11compound a methy group to a gene this
30:14compound can deactivate or at times
30:17activate the gene but the gene Remains
30:20the cell's DNA profile is unchanged
30:29this could explain the difference
30:30between identical twins Jake and
30:33Tom some as yet unidentified
30:36environmental factor in early cell
30:38development has caused a methal group to
30:41attach itself to a gene on one of Tom's
30:43chromosomes a gene associated with
30:47[Music]
30:49growth the growth Gene is still there
30:52but it's been switched
30:54off by investigating the mystery of
30:57twins like Tom and Jake geneticists are
31:00finally beginning to find Clues to some
31:02of the great Mysteries of the human
31:16genome this is a map of chromosomes
31:18belonging to identical twins from age
31:20three on the left to twins aged 50 on
31:23the right the red markings are an
31:26indication of the increase in the
31:28methylation that has occurred to their
31:30chromosomes over half a
31:32century we know that factors like
31:35smoking diet and chemical exposure can
31:38over a lifetime wreak havoc with how
31:40genes
31:41operate what's astounding is that there
31:44are different environmental influences
31:46in not only our lifetime but also in
31:49utero hormones space quality of
31:52nutrition can all affect identical
31:55embryos differently
31:59even those sharing a
32:01placenta the activation and deactivation
32:03of genes during early development could
32:06explain many of the twists of Fate that
32:08affect us all why one person is struck
32:11by disease while another spared
32:14epigenetics may also play a significant
32:16role in determining
32:19sexuality if sexual preference is
32:21associated with an as yet unidentified
32:24Gene it may be that the epigenetic
32:27suppression or activation of this Gene
32:29dictates sexual
32:34preference these genetic switches may be
32:37the answer to why one twin absorbs more
32:39testosterone than the other resulting in
32:42one being gay and the other
32:46straight it's becoming clear that our
32:49health personality tastes and even
32:51appearance are not the product of either
32:53our genes or our environment but that
32:56nature and nurture are inextricably
32:59bound with epigenetics the tangible
33:02biological link between the
33:04[Music]
33:06two and most surprisingly of all new
33:10research claims these subtle changes to
33:12a Gene's expression can be passed on
33:15down through the generations without
33:17affecting the underlying
33:21DNA studying a register of births and
33:24deaths in a remote region of Northern
33:26Sweden re Searchers noticed a peculiar
33:30phenomenon a generation of boys who
33:33experienced a famine had grandchilden
33:36who led longer
33:41lives on the other hand descendants of
33:45those boys who enjoyed plentiful food as
33:47children experienced an increased risk
33:49of diabetes cardiovascular disease and
33:53higher mortality rates
33:58the effect of famine was especially
34:00strong if the boy was at the age when he
34:03was just about to start producing
34:04reproductive cells is
34:08sperm it seems the genetic makeup of
34:11these reproductive cells were directly
34:14but subtly altered by the famine or
34:17Feast through their sperm they passed on
34:21a nutritional Legacy to Future
34:25Generations the more we explore the
34:28Hidden World of epigenetics the more it
34:31seems we are not simply a product of our
34:34genes we may even have the power to
34:37steer our genetic Destiny and perhaps
34:39that of our descendants through
34:41lifestyle choices such as smoking diet
34:45and
34:48exercise what makes identicals unique
34:50and useful to genetics is that their
34:53genome is 100% match or at least that's
34:57will be
35:01thought now powerful new DNA techniques
35:04are revealing a different story one that
35:07is only just
35:12unfolding as the second trimester draws
35:15to a close the twins will have a second
35:19scan the development of external
35:21features such as Limbs and eyes will be
35:23checked and the major organs will be
35:26examined for signs of defect
35:31the twins are about 20 cm long small
35:35enough to cradle in the palm of the
35:43hand the 20we scan is the time when most
35:46mothers will discover whether they're
35:48having a boy or a
35:54girl gender identification can be done
35:57as early as 11 to 12 weeks but is more
36:00certain at the 4 month
36:03scan the scan reveals our twins are
36:11boys our twins are 24 weeks into
36:20development their mother can now feel
36:23them kick
36:30inside the womb a battle for space is
36:33Raging a scan reveals this struggle and
36:36perhaps even a glimpse of emerging
36:42personalities ultrasound studies
36:44combined with observations of twins
36:46after birth show very early forms of shy
36:50or extrovert
36:53behavior in one study of fraternal twins
36:56the Shia twin would occasionally hang on
36:59to his umbilical cord and even appear to
37:01lick
37:02it while his sister would seek to grab
37:05kick and push
37:08him intriguingly this pattern continued
37:11after
37:13birth at 4 years of age the shy twin
37:17still exhibited retiring Behavior while
37:20his more extrovert sister would try to
37:22grab and play with
37:24him it seems our personalities May well
37:28begin to form in the
37:31[Music]
37:39womb from week 29 onwards the fetuses
37:43are beginning to resemble newborn
37:45[Music]
37:49babies their body fat rapidly increases
37:53bones are fully developed but still soft
37:56and pliable
37:58[Music]
38:03head hair grows thicker and fingernails
38:06reach the
38:09fingertips already our twins
38:11fingerprints are
38:14different epigenetic changes have
38:16already impacted the genes that control
38:19the pattern of the
38:20fingertips these fingerprint differences
38:23will become more
38:25pronounced as the fingertips develop
38:27they receive blood from the veins this
38:30makes them swell forming distinctive
38:33fingerprint
38:34patterns if blood flow from the placenta
38:37in one twin is restricted blood may be
38:40directed away from the fingers and other
38:42extremities leaving this twin with more
38:45whs on their fingerprints than the
38:48other our fingerprint patterns can help
38:50to indicate how unhealthy our heart will
38:53be in adult life the more whs the
38:57greater the chance of later heart
39:00[Music]
39:07problems from the moment a fertilized
39:09egg divides in two various influences on
39:12the genetic code conspire to create
39:14differences between identical
39:17twins differences that can become more
39:20pronounced over
39:23time yet it's always been assumed that
39:26identical twins sh identical
39:30DNA until a discovery in 2007 surprised
39:34the scientific
39:37World researchers set out to investigate
39:40one of the most puzzling anomalies in
39:42the life of
39:43twins why one succumbs to a genetically
39:46inherited disease while the other is
39:56unaffected they chose Parkinson's
39:58because it's more likely to be caused by
40:00a spontaneous genetic cause than be
40:03[Music]
40:07inherited so the scientists examined the
40:10genes of 19 pairs of identical twins
40:13including nine pairs in which only one
40:15twin showed signs of the genetic
40:22disorder they wanted to challenge the
40:24common perception that identical are
40:26genetic ially
40:28identical indeed their analysis showed
40:31that there were differences between the
40:33number of genes each twin
40:37had genes usually occur in two copies
40:41one inherited from each parent but this
40:44study has revealed it's possible to have
40:46just one copy or to have three or more
40:48copies of the same
40:50[Music]
40:53gene this phenomenon called copy number
40:56variation can fundamentally alter the
40:58Gene's function and may induce the
41:01disease in one twin and not the
41:03[Music]
41:16other it's a major breakthrough in our
41:19understanding of disease and in the
41:21study of
41:22twins because the discovery means that
41:25identicals are not a 100% genetic
41:29match the very definition of identical
41:32twins needs to be revised as advances in
41:35technology can prove that small but
41:37significant changes are present in all
41:39identical
41:41[Music]
41:44twins our identical twin boys are
41:46approaching full term already there will
41:49be subtle genetic differences between
41:51them that may shape very different
41:53futures
41:57but first they must face the most
41:59dangerous stage of their long journey in
42:01the womb the
42:07birth it's 35
42:15weeks the twins are now fully
42:21developed they have hair eyelashes nails
42:25and can open and close their eyes eyes
42:27and
42:28[Music]
42:31mouths conditions in the womb are
42:33becoming cramped at around 2 kilos each
42:37weighs about a third less than the
42:39average Singleton
42:43[Music]
42:45baby but combined they put tremendous
42:49pressure on the
42:52womb premature deliveries for twins
42:55before full term at 37 speaks are
42:59[Music]
43:05common our twins will be born at week 35
43:09by cesarian
43:11section about half of twins are
43:14delivered this way due to
43:18[Music]
43:22the to ensure safety there is a larger
43:25than normal delivery team one
43:27[Music]
43:36hand the obstetrician swiftly cuts the
43:39first membrane and then the
43:45second cesarians are always performed
43:48quickly to reduce the risks of
43:54complications he plunges his hand into
43:56the womb and takes the first baby
43:58[Music]
44:04out the baby takes his first breath and
44:07emits a healthy
44:08[Music]
44:12Scream the cord to the placenta his
44:15Lifeline for the last 35 weeks is
44:18finally cut
44:19[Music]
44:27[Music]
44:31working briskly the surgeon looks for
44:33his
44:34[Music]
44:37twin with his twin brother out of the
44:39way he follows quickly also head
44:44[Music]
44:50first following birth it's not always
44:53obvious to the obstetrician whether the
44:55twins are identical or
44:58fraternal our twins have a shared
45:01placenta the clearest indication that
45:03they are
45:06identical if the identicals have
45:08separate placentas as happens
45:10occasionally DNA analysis is the only
45:13sure method of
45:20[Music]
45:25identification after an extraordinary
45:28Journey our two reproductive Marvels
45:31have made it safely into the
45:33world they may look alike but we now
45:36know they are already
45:38[Music]
45:43different 245 days ago a fertilized egg
45:48divided creating two identical
45:53embryos from that moment onwards their
45:56paths began to
45:58diverge inequalities in nutrition or
46:02space differing exposure to
46:05hormones small alterations in their
46:08epigenetic profile even minute
46:11differences in the underlying
46:14genome all combined to create subtle yet
46:17significant
46:21differences now the twins are about to
46:23embark on the next stage of their
46:25Journey as they grow facing diverse
46:29experiences and influences the
46:31differences between them will become
46:33ever
46:38greater these differences bring us
46:40closer to answering some of Humanity's
46:42most profound
46:44questions the study of identical twins
46:47has shed new light on the complex mix of
46:49genetics and environment nature and
46:51nurture that makes each of us unique
46:57it has profound and far-reaching
46:59implications for how we all lead Our
47:02Lives
47:07[Music]

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