kamalktk
Antediluvian
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So rare doctors have identified only the second ever case.
https://www.cnn.com/2019/02/28/health/rare-twins-semi-identical-australia-trnd/index.html
more at link above:
"But in this case, Fisk said, when the egg was fertilized by two sperm, it split the three sets of chromosomes into two separate cell sets, thus forming the twins.
"Some of the cells contain the chromosomes from the first sperm while the remaining cells contain chromosomes from the second sperm, resulting in the twins sharing only a proportion rather than 100% of the same paternal DNA," clinical geneticist Dr. Michael Gabbett, who worked with Fisk, says.
The Australian twins share 89% of their DNA."
Semi-identical twins are rare, and doctors say they’ve identified the second case ever
You’ve probably heard of identical and fraternal twins, but a report published Thursday says there’s a third kind – sesquizygous twins or “semi-identical.”
Identical – or monozygotic – twins pop up from a single fertilized egg that eventually splits in two and forms two identical boys or two girls. They share 100% of their DNA.
Fraternal – or dizygotic – twins form from two eggs that have been fertilized by two of the father’s sperm, producing two genetically unique siblings. They share 50% of their DNA.
But “semi-identical” twins are so rare, experts say they have only identified two cases – ever.
Right along that DNA-sharing spectrum, “semi-identical” twins share anywhere from 50% to 100% of their genomes, researchers say.
And they’re extremely, extremely rare. The only other reported case of sesquizygotic twins was reported in the United States in 2007. The recently identified twins from South East Queensland are now 4 years old and healthy.
Details of this second case were published this week in the New England Journal of Medicine. Researchers from the University of New South Wales and the Queensland University of Technology combed through nearly 1,000 cases of twins to confirm their findings. ...
https://www.cnn.com/2019/02/28/health/rare-twins-semi-identical-australia-trnd/index.html
more at link above:
"But in this case, Fisk said, when the egg was fertilized by two sperm, it split the three sets of chromosomes into two separate cell sets, thus forming the twins.
"Some of the cells contain the chromosomes from the first sperm while the remaining cells contain chromosomes from the second sperm, resulting in the twins sharing only a proportion rather than 100% of the same paternal DNA," clinical geneticist Dr. Michael Gabbett, who worked with Fisk, says.
The Australian twins share 89% of their DNA."
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