“Eventually it comes to you: the thing that makes you exceptional, if you are at all, is inevitably that which must also make you lonely.” ~ Lorraine Hansberry
Chimeras or “mosaics” (as some refer to the condition) have two types of DNA or genotypes in the body. Additionally, it’s recently been discovered that a section of genetically incompatible cells may contribute to conditions like autism and infertility, along with Alzheimer’s. With in vitro fertilized babies on the rise, the increase of in vitro-infertilization has resulted in increased chimeras. In the process surgeons place two or more embryos in a woman’s uterus to increase the success rate. So the in vitro baby essentially is “made-up of two women.” Also, 25 percent more twin pregnancies occur because of this procedure. Thus, more cases of twin pregnancies result in more chimeras. Bonthron proved this—discovering the British hermaphrodite boy proved a chimera formed by in vitro fertilization. Another possibility reflects two different sperm had developed unusually into a single mature egg before cell diffusion had occurred.
Most cases of chimeraism consist of non-identical twins that share a blood supply in the womb: blood chimeraism. Often
twin embryos can share a blood supply in the placenta. But the rarest
cases of chimeraism—TRUE cases--remain when many tissues of the body are
affected. It happens when non-identical twin embryos shortly join
after fertilization. Geneticist David Bonthron of the UK’s University
of Edinburgh studied the hermaphrodite boy. Of course, any time you
have two embryos the chance increases they can unite as one. In 1995
Bonthron discovered a partially parthenogenic boy—meaning the cells from
some of other tissues and his blood didn’t possess any of his father’s
chromosomes. (But it isn’t alien for an egg to start development
without fertilization. The parthenogenic embryo will not develop to
term.) Dr. Bonthron (who is now at Leeds in the UK)—believes the partly
parthenogenic boy received his strange genetic constitution because of
an egg that abruptly divided into two cells: one that fertilized; the
second cell afterward copied its maternal chromosomes. This allowed the
feasibility of the resulting chimera.
The mythology of the chimera explains its implementation in today's medical language.
In mythology the chimera has a history of the creature of the
sky--possibly linked to storm and thunder. The chimera remains among
the stars as the winter constellation Capricorn--along with Pegasus, who
happens to chase her across the heavens. The legend of the
mythological chimera includes its brother, Cerberus (the Hound of Hell)
and its sister, Hydra (the nine-headed water snake), along with Orthrus
(the two-headed dog). The chimera was the offspring of Typhon (a
destructive storm god) and Echidna (a winter snake goddess). In the end
Bellerophon defeated it with Pegasus' help--by the order of King
Lobates of Lykia. Chimera's flaming breath melted the lead-tipped spear
of Bellerophon and died. The fire-breathing monster had the head of a
lion, the body of a goat with a dragon at hindquarters. Although
traditionally thought to be female, evolution has spawned creatures that
possess both male and female cells: a hermaphrodite.
Most people don't realize the
representation of the symbol of Bellerophon and the Chimera as
representative of good triumphing over evil. Mostly likely, it is
the foundation for a more well-known medieval story: St. George slaying
the dragon. Thus, human chimeras were initially discovered when
blood-typing came to the forefront--with the realization of humans with
more than one blood type.
As a side note, often folks from England
use "chimera" in the reference: "allowing that to happen once more by
creating a "chimera" of a situation already dire enough that can finish
one off. And that "the sooner one overcomes their "chimeras" the
sooner he has the ability to move ahead and improve his life: to make a
better life for oneself.
