CHIMERA/ HYBRID - (Dec/20/2006 )

hello

just a small wondering,
i was looking for some info about chromosome mutation ....and many times read these two words: Chimera and Hybrid....what is the difference between them?

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Normally hybrids are a cross between different strains/races or whatever, i.e. heterozygous. Chimeras are spezimen mixed together of cells or tissue containing different genomes. Thats what I learned, but these terms are used not very consistent.

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HI hobglobin,

i'm confused since the time i read a sentence (may be in wikipedia, not sure ) saying that "hybrid" is different than "chimera"..

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I am just taking a guess here, and please correct me if I am wrong: hybrid- like if you cross red tomato with yellow one, you get pink-orange color, the daughter generation has homogenously distribution of phenotypes from both parent stains; on the other hand, Indian corns have different colors for each grain. The daughter generation has a very heterogamous phenotype distribution. Is that called chimera?

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You can have a look at the definition of chimera here: http://www.medterms.com/script/main/art.asp?articlekey=8905

while for hybrid here: http://www.medterms.com/script/main/art.asp?articlekey=3822

In conclusion: a cross between two species is a hybrid while an organism with two different tipes of cells is a chimera.

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yup DNAfactory is correct.

A hybrid is a cross of two species. Ie the chromosomes of two species (....in some ratio) share the same nucleus.
A chimera is a organism whose tissue is composed of cells from two species. There is no mixing of genes. Each species's chromosome is contained in separate cells and in its own nucleous.


So if you were to isolate a single cell from a hybrid of species A and B and grew it into an adult animal. What you will get will be another another hybrid.

On the other hand, if you were to isolate a singe cell from a chimera of species A and B, and grew it. The resulting creature will be either an animal from species A or an animal from species B, depending on the species of the cell that you initially picked.

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Interestingly females (at least in humans and most mammals) could be considered chimaeras as one of the X chromosomes is inactivated in each cell, thus some cells have the maternal X and some have the paternal X functioning, thus you have different lineages of cells in the body!

My genetics lecturer used to say that this is what allows women to change their minds every five minutes

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well then, if you want interesting, there was a discovery in mice. Female mice who have been pregnant often have cells from their young in their blood stream. (nothing new here). It was however discovered that some these cells are pluripotent stem cells which can integrate themselves into sites like the bone marrow, differentiating into red and white blood cells. Thus female mice (and I won't be surprice if this is true for all mammal moms) become a tinny bit more of a chimera after each pregnancy.

(the rational for this has been speculate to go something like this "It is in the best interest for the pups if their mother was healthy. So by given her extra diversity in her immune system, she can better fight off infection and thus better care for the pup in question. This rational is pure speculation.)

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well, thanks all

so, can we use "intra" and "inter" here !!?
according to you, we can say that calico cats are chimera...right!
what about crossing-over here?

i need to have a clear picture joining all these ..

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yes, it's wikipedia, have a look..
http://en.wikipedia.org/wiki/Hybrid_animals

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