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Siamese twins
Name: cwarrin
Status: N/A
Age: N/A
Location: N/A
Country: N/A
Date: Around 1993
Question:
How are Siamese twins formed, and what is the chances of having
them?
Replies:
Siamese twins are formed when monozygotic twins (arising from a
ingle fertilized egg) fail to completely separate from each other during the
process of cell division. In a "regular" pregnancy, a single fertilized egg
will undergo cellular division, the cells eventually differentiating into
distinct organs and tissues. In the case of identical twins, however, a set
of circumstances which are not entirely understood causes a separation of
cells early in the division process, before actual differentiation begins, and
the two halves then go on to form complete fetuses. Siamese twins, however,
separate late in the division process, perhaps even after differentiation of
cells has begun, and thus form into two fetuses with certain tissues or cell
masses shared between them, due to their failure to separate completely before
then.
Wordsworth
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Update: June 2012
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