Comments on: Chimeras walk among us...

Chimeras walk among us...

o2b — Wed, 24 Sep 2003 12:35:59 -0800

"Hybrid Humans" Very early on in the womb, two fertilized eggs that would have normally created fraternal twins will occasionally fuse to form one embryo, producing a "chimera": one person with two sets of DNA. The link goes to a Nature article, here is an NPR piece.

By: aladfar

aladfar — Wed, 24 Sep 2003 12:39:15 -0800

I head that story the other day just as I was waking up - in that groggy space between consciousness and sleep. It really freaked me out.

By: o2b

o2b — Wed, 24 Sep 2003 12:51:25 -0800

Hypothetical: A chimera is arrested, with motive, opportunity and no alibi. A hair is found at the scene of the crime. Its DNA is tested against the DNA of the suspect -- not the same! It's a Law and Order situation -- imagine the appeals that would hit the system if DNA evidence were found to be unreliable.

By: adamrice

adamrice — Wed, 24 Sep 2003 13:16:16 -0800

02b--that's exactly the kind of scenario mentioned in the NPR piece, which is fascinating in general (everyone should give it a listen). The reporter makes the point that if you, say, collect hair from the crime scene, you need to collect hair from the suspects to establish the DNA--a cheek swab might be DNA from your "missing twin". Or your hair might be. Uhh, whatever--it's hard to keep straight. Also interesting is that chimerism is thought to be "very rare" but nobody knows how common it really is.

By: dabitch

dabitch — Wed, 24 Sep 2003 13:46:16 -0800

awesome. I hope I'm a chimera, coolest thing I've heard about in a while, thanks for link.

By: dabitch

dabitch — Wed, 24 Sep 2003 13:48:22 -0800

(eh, but i'm not a hermaphrodite... just to clear that up. heh.)

By: Shoeburyness

Shoeburyness — Wed, 24 Sep 2003 14:53:08 -0800

Fascinating article. Good post. Perhaps chimerism/mosiacism is more common than we now think-- it used to be thought that having twins by two different fathers was extremely rare. Now that we have DNA typing, it's been found that it is much more common than previously thought (but still somewhat rare.)

By: shoepal

shoepal — Wed, 24 Sep 2003 14:58:47 -0800

Sometimes I wish I was a mozilla.

By: yhbc

yhbc — Wed, 24 Sep 2003 15:01:36 -0800

Although it is not unknown for an egg to start developing without being fertilized, fully parthenogenetic human embryos cannot develop to term. With one possible counter-example having been reported in the Bethlehem region, approximately 2007 years ago.

By: Samsonov14

Samsonov14 — Wed, 24 Sep 2003 15:05:25 -0800

Any "overlords" comments and I swear I'll jump through your monitor and punch you in the neck. You've been warned.

By: skallas

skallas — Wed, 24 Sep 2003 15:22:16 -0800

>With one possible counter-example having been reported in the Bethlehem region Actually, many have claimed virgin birth, even historical figures like Caesar. It was something of a proof of divine nobility. Not to mention other fatherless religious figures who predate Mary's vigin conception.

By: adamrice

adamrice — Wed, 24 Sep 2003 15:36:15 -0800

I, for one, welcome our new running-gag overuse guardian.

By: Samsonov14

Samsonov14 — Wed, 24 Sep 2003 17:05:58 -0800

Damn straight.

By: arto

arto — Thu, 25 Sep 2003 01:05:56 -0800

Fatherless children have a hard time when father is God, lord. (with deep, deep apologies to Blind Willie Johnson and the Rev. Gary Davis) It's a Law and Order situation -- imagine the appeals that would hit the system if DNA evidence were found to be unreliable. Not necessarily... This doesn't mean identical DNA samples can be from different people, but rather that non-identical DNA samples can be from one person. (As I understand it--I'm no molecular biologist.) So it probably wouldn't be useful to overturn DNA evidence convictions, but might make it harder to use DNA to prove people's innocence.

By: hattifattener

hattifattener — Thu, 25 Sep 2003 01:35:02 -0800

"I'm convinced that on the streets of London and Hamburg there are many undetected chimaeras," says Rudolf Happle, a dermatologist at the University of Marburg, Germany

Fascinating post, o2b.

By: joquarky

joquarky — Thu, 25 Sep 2003 13:51:41 -0800

With one possible counter-example having been reported in the Bethlehem region, approximately 2007 years ago. And one other possible counter-example a long-long time ago, in a galaxy far-far away...