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Animal Chimeras / Chimaeras

ramonmercado

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I'll Be a Monkey's Uncle
By Erin Wayman
ScienceNOW Daily News
26 March 2007

We get half our genes from mom and half from dad, but marmosets get something extra from their siblings. While in the womb, these small South American monkeys swap stem cells with their fraternal twins, giving each a genetic piece of the other. Now scientists have discovered that this chimerism extends to sperm cells, which means that when one of these twins grows up, he can actually sire his brother's offspring. The finding may help explain the unusual parenting behavior seen in these monkeys, researchers say.
Marmoset females almost always give birth to fraternal twins. This type of twinning results when two egg cells are fertilized by separate sperm. Because each sperm and egg cell contains different DNA, one twin has a different genetic makeup than the other. Scientists have known for years that marmoset twins exchange stem cells--which can develop into a variety of cell types--through their shared blood supply during pregnancy, but they had only seen evidence of genetic mixing in blood cells.

In the new study, Corinna Ross, a primatologist at the University of Texas Health Science Center in San Antonio, and her colleagues discovered chimerism in a variety of other tissues, including the liver, heart, and sperm. As a result, the pool of sperm of one twin can be a mix of his own sperm and his brother's sperm. When the twin breeds, he could potentially sire a nephew instead of a son, the researchers report online this week in the Proceedings of the National Academy of Sciences.

This unusual inheritance may explain the selective parenting behavior exhibited by marmoset dads, who tend to pay more attention to some offspring than others. Ross's team found that marmoset fathers carry their chimeric infants more often than nonchimeric infants. That makes sense, says Ross, because when one twin receives stem cells from another, he is essentially inheriting "extra" DNA from his father's side of the family. Somehow, dads are able to pick up on this chimerism to more easily recognize their own offspring in a population where paternity can be in doubt, she notes.

"It's a really exciting result and ... adds a lot more depth" to our understanding of marmoset behavior, says Charles Snowdon, a biological psychologist at the University of Wisconsin, Madison. But, he adds, genetic chimerism isn't the only thing influencing family life in these monkeys. A host of other factors, such as previous parenting experience, group social dynamics, and hormones, can also affect how much attention dads pay to their kids.

http://sciencenow.sciencemag.org/cgi/co ... 2007/326/3
 
Published online: 26 March 2007; | doi:10.1038/news070326-5

Who's your daddy?
Marmoset families have mixed-up genetics.
Heidi Ledford



As a general rule, a man who learns that his children are genetically his brother's offspring would have good cause for distress. But for one group of primates, that wouldn't necessarily mean that mum has been unfaithful, a new study finds.

The reason, says Corinna Ross of the University of Texas Health Science Center in San Antonio, is that these primates are often genetic mosaics containing some cells that belonged to their siblings. And when those cells happen to be sperm, a male can sire offspring that are genetically nephews and nieces rather than sons and daughters.

This strange genetic mixing could be one of the reasons why these animals tend to raise their families in large collectives, with everyone lending a hand; animals are thought to generally give more parental attention to children with a strong genetic similarity to themselves.

The discovery was made accidentally when Ross was studying small, tree-dwelling primates called black tufted-eared marmosets (Callithrix kuhlii) at the University of Nebraska in Lincoln. The marmosets that she studied were being kept in captivity, with two senior males for every reproducing female. Ross wanted to test the paternity of the colony's offspring, to find out which male was the father of each child; to do this, she looked at hair samples of various animals to determine their genetic make-up.

But her results were confusing: some hair samples showed the genetic fingerprint of a sibling rather than that of the individual being tested.

Cellular mix

Scientists have known for years that marmosets — which are typically born in pairs — share a blood supply with their twin while developing in the womb. As a result, most marmosets contain blood cells from their siblings, and therefore carry their sibling's genes as well as their own. But the phenomenon — known as chimaerism — had only been observed in marmoset tissues that produce blood cells.

Ross went on to test 15 different tissue types — from kidney to skin to sperm — in 36 sets of marmoset twins from 15 families. A percentage of samples from every tissue tested contained the genetic information from a sibling rather than the animal that provided the tissue sample, she reports in Proceedings of the National Academy of Sciences1. Of the hair samples, 17% were chimaeric.

Some cells are producing sons and daughters, whereas others are producing nephews and nieces

David Haig, Harvard University




Finding chimaerism in reproductive tissue is particularly surprising, says David Haig, an evolutionary biologist at Harvard University in Cambridge, Massachusetts. "That means that when a marmoset reproduces, some of the cells from that marmoset are producing sons and daughters, whereas others are producing nephews and nieces," says Haig.

Ross found chimaerism in four of the seven sperm samples that she analysed; in 5 of the 15 families, members passed a sibling's genetic information on to their offspring. In one particularly odd case, a female passed her brother's genetic information on to her children - suggesing the intriguing possibility that the mother may have passed a Y chromosome to her offspring.

Family ties

All this could have an impact on the family dynamics, says Haig.

Marmoset families are highly cooperative, and the entire family helps to raise the young. Marmoset mums hand much of the childcare over to dad, who carries his offspring on his back as he scampers from tree to tree. Older siblings also help out, and often opt to help raise their younger brothers and sisters rather than have children of their own, freeing up mum to get pregnant again more quickly.

Chimaerism could facilitate that family harmony, agrees Ross, because a sibling carrying a mosaic of the family's genetic information is more likely to share some of that information with each family member, strengthening kinship bonds among siblings. "For example, their parents could be having infants that are more closely related to them than their own infants might be," says Ross.

It does seem to have an impact on families, Ross found. She looked at the amount of chimaerism in the skin of baby marmosets, to see if that external (and relatively easy to measure) signal of a genetic mix had an effect on parenting. It did.

Fathers spend more time carrying infants with chimaeric skin than infants who were not skin chimaeras, she found. Mothers, on the other hand, spend less time with these chimaeric offspring, perhaps knowing that others would pick up the slack. Exactly why dads seem to invest more in chimaeric offspring isn't yet clear.

Visit our newsblog to read and post comments about this story.


References
Ross C. N., French J. A. & Orti G.. Proc. Natl Acad. Sci. USA, doi:10.1073/pnas.0607426104 (2007).


Story from [email protected]:
http://news.nature.com//news/2007/070326/070326-5.html
 
Venus, the chimera cat.

Remote-linked image is MIA. Here's another image of Venus the chimera cat, plus a link to an informative article about her ...

58818.adapt.1900.1.jpg

SOURCE & ARTICLE: https://www.nationalgeographic.com/news/2012/9/120831-venus-two-faced-cat-genetics-animals-science/
 
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Scientists create ‘Frankenstein’ chimera monkey that glows green

The birth of a chimeric monkey with glowing green fingers and eyes may sound like something out of a horror movie, but it represents a major scientific breakthrough.

Researchers in China announced the ‘long-sought’ birth today, sharing images of a long-tailed macaque whose cells are made from an embryo injected with other, genetically distinct cells.

chimera-1.png


The study, published in the journal Cell, used later stage pluripotent cells, meaning they have the ability to differentiate into all the types of cells needed to create a live animal.

‘This is a long-sought goal in the field,’ said study leader Dr Zhen Liu, of the Chinese Academy of Sciences (CAS).

‘This research not only has implications for understanding naive pluripotency in other primates, including humans, but it also has relevant practical implications for genetic engineering and species conservation.

‘Specifically, this work could help us to generate more precise monkey models for studying neurological diseases as well as for other biomedicine studies.’

https://metro.co.uk/2023/11/09/scie...ein-chimera-monkey-that-glows-green-19800626/

maximus otter
 

Scientists create ‘Frankenstein’ chimera monkey that glows green

The birth of a chimeric monkey with glowing green fingers and eyes may sound like something out of a horror movie, but it represents a major scientific breakthrough.

Researchers in China announced the ‘long-sought’ birth today, sharing images of a long-tailed macaque whose cells are made from an embryo injected with other, genetically distinct cells.

chimera-1.png


The study, published in the journal Cell, used later stage pluripotent cells, meaning they have the ability to differentiate into all the types of cells needed to create a live animal.

‘This is a long-sought goal in the field,’ said study leader Dr Zhen Liu, of the Chinese Academy of Sciences (CAS).

‘This research not only has implications for understanding naive pluripotency in other primates, including humans, but it also has relevant practical implications for genetic engineering and species conservation.

‘Specifically, this work could help us to generate more precise monkey models for studying neurological diseases as well as for other biomedicine studies.’

https://metro.co.uk/2023/11/09/scie...ein-chimera-monkey-that-glows-green-19800626/

maximus otter
This reminds me of the premise for George Romero's 'Monkey Shines' film. I think the same technique you've reported in your above post has previously been successful in mice and it's something to do with using jellyfish genetics from memory?.



edit:

Glowing mice

https://www.understandinganimalresearch.org.uk/news/glowing-mice

Glowing cats

https://www.bbc.co.uk/news/science-environment-14882008
 
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