Researchers Create First Genetically Modified Monkeys

Several readers tipped news that U.S. scientists have created 'chimeric' monkeys, made with genetic material from as many as six different genomes (abstract). This is significant because it's the first time researchers have used the technique on a primate. From the article: "Researchers took very early stem cells, called totipotent stem cells, from separate developing embryos and basically glued them together, implanting the mixed embryos into surrogate mother monkeys. The cells — from totally different sources — didn’t fuse, but worked together in harmony, forming fully fledged, normal, healthy animals. ... The key here was the scientists’ use of totipotent cells, so named for their ability to differentiate into the totality of possible cells in an animal. A totipotent cell can give rise to a whole animal. Pluripotent stem cells, the type most frequently used in stem cell research, can differentiate into any cell in the body, but can’t become a whole animal, and can’t make other embryonic tissues like a placenta. Totipotent stem cells are only derived from the very earliest stages of a zygote, mere days after fertilization. In humans, totipotent cells differentiate into pluripotent cells after four days."

Re:Different genders?

[Remus Shepherd]

Mixed-gender chimeras happen in real life. In general it's not a huge problem for the organism. One part of the animal contains the sex organs, and those organs are appropriate for the genes in that part. The hormones are often wacky, of course. Yes, you can get hermaphrodites this way.

You may be under the impression that a chimera is a homogenous mix of cells from different gene lines. Actually, the gene lines usually occur in 'clumps' throughout the organism. The right arm might be all one gene line, while the torso is another, and the left arm yet a third. The clump around the lower abdomen will determine which sex organs develop.

Re:Human-chimp hybrids coming soon?

[rubycodez]

No, Chimps are not great playmates nor nannies. If they get it into their head to attack, for many times unclear reasons, they instinctely follow a pattern of destruction of the enemy primates body. first they will gnaw off your child's fingers. Then they attack your precious little one's face by biting off parts. They then start to dismember, ripping off limbs.

Chimps are unpredictable and extremely dangerous. Many people have been maimed or killed by their pet chimps.

Re:Sounds very Frankensteinish

[GameboyRMH]

Chimeras occur in nature and AFAIK there are no negative health effects so I don't think tissue rejection is an issue...

Re:Not genetically engineered?

[Hatta]

No, it makes it less striking. Chimeras occur naturally when fraternal twin zygotes fuse at an early stage. The interesting result here isn't the production of the chimeras. There's no technical reason that we would want to create chimeras. The chimera is just proof that the stem cells they used were totipotent.

Re:Different genders?

[SuricouRaven]

Depends how you define 'gender.' Do you want an organism that is genetically male but anatomically female, or vice versa? That's easily done, certainly in any species that uses the XY chromosome system like humans. If no scientist has done it yet, it is only because there is no reason to. One tiny little genetic change to disable the TDF gene and you get a genetically male female, or one tiny adjustment to hormone levels in utero for a genetically female male. Humans don't start to develop gender-specific features until well into the fetus stage - they all start developing as a female. That is why men have nipples.

Re:Not genetically engineered?

[glwtta]

There's no technical reason that we would want to create chimeras.

Sure there is, most genetically engineered mouse models (for example) involve a chimeric step in their creation: stem cells with the desired modification are injected into 'donor' blastocysts and implanted into a host female, producing chimeras which are then bred for several generations to create homozygous offspring.

Re:Sounds very Frankensteinish

[Alphadecay27]

The word "chimera" means it is cross species; the chimeric monkey being a mosaic of varied monkey species cells.

Your vast knowledge of greek literature (or alternately the AD&D monster manual) does not apply here. The term just means the animal has two distinct genetic pools.

The original article specifies that: The chimeric monkeys were born after the researchers essentially glued cells from separate rhesus monkey embryos together. http://www.eurekalert.org/pub_releases/2012-01/cp-wfc010412.php [eurekalert.org]