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Identical Twins

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bemahan
720034.  Wed Jun 16, 2010 4:48 am Reply with quote

Ok, so this could be one for the ‘T’ series or the ‘M’ series (monozygotic), but they are a long way away…
An initial question about identical twins could be asked and the topic could then possibly widen out into other twin types.

A good combination of trivia and scientific data, perfect for a QI question!

Identical (monozygotic) twins/triplets are the result of a single egg splitting after conception. These twins will share 100% of their DNA. They are the same sex. have the same blood types. hair and eye color. hand and footprints and chromosomes. yet have different teeth marks and fingerprints. Environmental influences can determine that characteristics such as height. weight. ears. nose. lips are somewhat different. Some monozygotic multiples are told they are fraternal (dizygotic) - only DNA testing provides conclusive results.

Mirror Image twins account for about 25% of identical twins. Their hair falls in opposite directions. they have mirror image fingerprints and if one is right handed. the other is left handed. There is no specific test for determining if twins are mirror-image. however. The determination is made by observation only. and the twins must be monozygotic (identical).

There are a lot of interesting ‘facts’ about twins (identical or otherwise) on this site. http://www.twinsuk.co.uk/twinstips/18/144/multiple-birth-statistics,-facts-&-trivia/having-twins-or-triplets---interesting-&-fun-facts/

Here’s a few I picked out:
• Worldwide there are at least 125 million living multiples.
• The incidence of twin types and genders are oddly symmetrical. One third of all twins born are identical. one third are same sex fraternal. and one third are male/female fraternal. Of the identical twins. half are male/male. and half are female/female. Of the same sex fraternal. half are male/male. and half are female/female. Additional source:http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Twins_identical_and_fraternal
• Did you know that up to 22 percent of twins are left-handed. In the non-twin population the number is just under 10 percent. http://www.bbc.co.uk/dna/h2g2/A535510 backs this up (Edit: two other sites say that about 20% of identical twins have different handedness i.e. one is left and the other right-handed)
• Identical twins exhibit almost identical brain wave patterns.
• Twins and multiples have been know to develop their own 'language' that only they understand. This is known as cryptophasia or idioglossia.
• The average time between the delivery of the first and second twin is 17 minutes
Nigeria has the highest rates of multiples with more identical twins than fraternal. while China has one of the lowest with multiple births occurring one in 300 births.
• Scientists believe that the number of twin conceptions greatly outnumbers the number of twin births. some say that as many as one in eight births began with twins. while in only one in 70 births produce twins. One author claims that "80% of twin pregnancies result in the loss of one or both babies." though other sources cite this number at about 30%. Of the 133 million people born worldwide in 2000. an estimated seven million should have been twins.

Some ‘fun facts’ from this site http://www.twinsworld.com/stats.shtml

• A peasant named Kirilow was presented to the empress of Russia in 1853 for the following reason. He had been married twice. His first wife bore fifty seven children, including four sets of quadruplets, seven sets of triplets, and two sets of twins. His second wife gave birth to fifteen children-six sets of twins and one set of triplets. At the time of his presentation to the empress, all seventy two of Kirilow's children were still alive.
• Mrs. Mary Jonas (d. 1899) had 15 sets of boy/girl twins.
• A woman from Italy had 11 sets of fraternal twins in 11 years the last being in 1947 - not all of them survived.
• Marcella Mills-Bigcrow of Pine Ridge, South Dakota had 8 sets of twins,
along with 8 single births. All the babies survived, and were born between the 1940's and 1960's.
• Mrs. Barbara Zulu of South Africa had 6 sets of twins in 7 years (1967-73, 3 sets of girls, 3 mixed)

There is loads of scientific data on Wiki.

There may already be twin-related data on the forums but there were 16 pages of matches when I searched! There was one in Feb this year about " Children of two sets of twins that marry" on Quite Interestrings.

Your mission, should you choose to accept it, is to sort the fact from the fiction! I'm away now to try to do just that....

 
Jenny
720216.  Wed Jun 16, 2010 3:25 pm Reply with quote

The propensity to have twins is, to some extent, hereditary, but only for fraternal twins. There can be a hereditary tendency to release more than one egg at a time (known as hyperovulation).

http://multiples.about.com/od/funfacts/tp/howtohavetwins.htm

 
Arcane
750751.  Sun Oct 10, 2010 6:43 am Reply with quote

Very QI case:

There has been a case of semi-identical twins; where they shared all the genetic information from their mother, but only 50% from their father. One twin was born with ambiguous genitalia, that turned out to be hermaphroditic. It was later revealed that they are in fact chimeras and share both male and female genetic material.

http://www.abc.net.au/science/news/stories/2007/1882330.htm


http://news.bbc.co.uk/2/hi/6498215.stm

"In this case, the researchers say the twins probably arose when two sperm cells fused with a single egg, creating an embryo with three sets of chromosomes rather than two.

There was a mixing of genes within the double-fertilised egg, which then split into two cells before shedding an unwanted set of chromosomes.

As a result, the children would have identical genes from their mother's side but would share only half their genes on their father's side."


It opens the door for the fact that classifying twins may not be as simple as first thought.

 
djgordy
828460.  Sat Jul 02, 2011 11:28 am Reply with quote

bemahan wrote:

Mirror Image twins account for about 25% of identical twins. Their hair falls in opposite directions. they have mirror image fingerprints and if one is right handed. the other is left handed. There is no specific test for determining if twins are mirror-image. however. The determination is made by observation only. and the twins must be monozygotic (identical).


The tennis playing Bryan brothers seem to be mirror twins. Bob is left handed and Mike is right handed.

 
WordLover
844991.  Sat Sep 10, 2011 5:31 am Reply with quote

Jenny wrote:
The propensity to have twins is, to some extent, hereditary, but only for fraternal twins. There can be a hereditary tendency to release more than one egg at a time (known as hyperovulation).
Indeed, and the incidence of fraternal twinning varies from one population to another. In Japan, it's 1 birth in about 160; here, 1 in about 80; among the Yoruba, nearly 1 in 20, possibly thanks to their eating white yams which "contain a phytoestrogen which may stimulate the ovaries to release an egg from each side" (Wikipedia, Twin).

 

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