It's Not Your Daddy's DNA...

[xssve]

Turns out it's not all cut and dried when it comes to expressing proteins:

It turns out, for example, that several different proteins may be produced from a single stretch of DNA. Most of the molecules produced from DNA may not even be proteins, but another chemical known as RNA. The familiar double helix of DNA no longer has a monopoly on heredity. Other molecules clinging to DNA can produce striking differences between two organisms with the same genes. And those molecules can be inherited along with DNA.

The gene, in other words, is in an identity crisis.

Now: The Rest of the Genome

 

[TheeGoatPig]

All of a sudden, a line on the show Farscape has a lot more credibility.

Jon Crichton: Couldn't you just take a blood or saliva sample?

Creature/scientist: Maybe, if I were only working on the double helix level.

 

[Equinoxe]

http://bloc.jmones.net/media/copycat_rainbow.jpg

The cat on the left (CC) is a clone of the cat on the right (Rainbow).

 

[Safe_Bet]

http://bloc.jmones.net/media/copycat_rainbow.jpg

The cat on the left (CC) is a clone of the cat on the right (Rainbow).

Gee, clones are a lot smaller aren't they.

 

[Equinoxe]

Gee, clones are a lot smaller aren't they.

Not even clones can escape the trauma of childhood.

 

[Safe_Bet]

http://bloc.jmones.net/media/copycat_rainbow.jpg

...... Whoo, Dude! ................................... Heeheehee!
...... Back off with................................... This should be
...... with that rectal ............................... fun to watch!
...... thermometer!

 

[3113]

http://bloc.jmones.net/media/copycat_rainbow.jpg

The cat on the left (CC) is a clone of the cat on the right (Rainbow).

Well, but with cats you have a problem when it comes to cloning them exactly. Mamma cat's womb influences fur shading and color. So there's no way to make sure that a clone of a kitty will have the exact same coloring as the original.

 

[Selena_Kitt]

Well, but with cats you have a problem when it comes to cloning them exactly. Mamma cat's womb influences fur shading and color. So there's no way to make sure that a clone of a kitty will have the exact same coloring as the original.

really? that's fascinating!

 

[3113]

really? that's fascinating!

Here's some elaboration (and to be specific, this has to do with multicolored cats; I don't know if solid color cats differ). This explanation is about tortoiseshell/calico cats in particular:

...if you clone a tortoiseshell cat you will end up with a cat of one or other of the constituent colours and not a tortoiseshell clone. If you clone a red/black tortoiseshell, the clone will be either red (ginger) or black....The pattern of pigmentation in multicoloured animals is the result of genetic factors combined with developmental factors within the womb. This means bad news for owners who want an exact replica of a tortoiseshell or calico cat.

Tortoiseshell cats have two X chromosomes, one carrying the gene for orange coat colour and the other carrying the gene for black coat colour. As the embryo develops, a process called ‘X-linked inactivation’ occurs in its tissues. One or the other X-chromosome in every cell in a tortie cat embryo is randomly inactivated. This only shows up in pigment producing cells, producing the familiar tortie effect.

Regardless of which cell was used [to create the clone]...one or other of the cell's X chromosomes would have been inactivated while the donor cat was an embryo. [The cloned cat has] an equal chance of being orange-tabby-and-white or black-tabby-and-white, but would never be tortie-tabby-and-white. Unless a way can be found to undo X-linked inactivation at the embryo stage, owners wishing to clone a tortoiseshell cat will have to settle for a cat of a different colour entirely. If the X-linked inactivation can be reset, the inactivation is a random process so the clone will have the right colours, but not in the same places as the donor cat - it may have well-defined patches of colour while the donor cat was thoroughly brindled.

 

[Stella_Omega]

Well, but with cats you have a problem when it comes to cloning them exactly. Mamma cat's womb influences fur shading and color. So there's no way to make sure that a clone of a kitty will have the exact same coloring as the original.

And in some ways this is true of all mammals, including humans.
http://en.wikipedia.org/wiki/Epigenetics

There's a breed of mice that are born diabetic. Researchers have treated pregnant mice with proteins that turn off the diabetes, and produced non-diabetic babies-- that breed true.

Kinda cool, huh?

 

[Equinoxe]

Well, but with cats you have a problem when it comes to cloning them exactly. Mamma cat's womb influences fur shading and color. So there's no way to make sure that a clone of a kitty will have the exact same coloring as the original.

Well, with every species you have a problem with cloning them exactly, because you can only clone something genetically—you can't clone something epigenetically.

That a cat has a tortoiseshell and white coat is genetic: ergo CC and Rainbow are both tortoiseshell and white cats, because they possess the genes for a tortoiseshell and white coat. How exactly the pattern is expressed, though, is epigenetic—tortoiseshell and white patterns are dependent upon X Chromosome inactivation (this is also why the vast majority of tortoiseshell cats are female, since a cat has to have two X chromosomes to have such a coat pattern). Which X chromosome is activated in each cell, however, is not subject to genetic control: thus while the genes in two cloned cats are identical, the expression of them isn't, and hence they do not appear the same.

The same thing occurs in human beings who are genetically identical, albeit in less obvious ways—and increasingly so over time (that is, identical twins are more phenotypically identical when they are younger).


Edited to add: I should type faster.

 

[trysail]

NOVA ( a televised U.S. PBS science series for those not familiar with it ) had a nice program last fall on the epigenome and the environmental factors that cause methylation of the genome. One of the studies that led science in that direction arose from the availability of records documenting the epidemological effects of a late 19th century famine on an isolated Swedish village. The diets of those Swedish grandparents ( i.e., "nurture" as opposed to "nature" ) had a high correlation with health outcomes of their grandchildren not otherwise suggested by genetic factors; this lead scientists to study the population and eventually propose epigenomic causation.

As noted by Equinoxe, it is the individuation of the epigenome that determines different health outcomes for identical twins.

That particular NOVA program was an extremely effective at explaining an incredibly complex subject. It was a well-spent hour.

As many know, isolated populations who maintain multi-generational public health records are fertile ground for genetic research. For that reason, Iceland is a genetics gold mine. Other groups that have made a mighty contribution include the Amish.

 

[Safe_Bet]

And in some ways this is true of all mammals, including humans.
http://en.wikipedia.org/wiki/Epigenetics

There's a breed of mice that are born diabetic. Researchers have treated pregnant mice with proteins that turn off the diabetes, and produced non-diabetic babies-- that breed true.

Kinda cool, huh?

Oh nice thing to tell the pregnant lady you guys! "Hey, Selena your kid could be born with a bunch of different hair colors!"
(It WILL be fun watching her explain that to her Hubby, though!)

 

[dr_mabeuse]

I knew it! I knew that protein theory of genes was bullshit! It's just too simplistic, and it doesn't explain the protein-folding problem, how it is these complicated proteins know how to fold themselves into the right configuration to be useful. If they don't fold right, you get these prions, toxic proteins like those that cause mad cow disease.

Only like 1.2% of the entire genome makes proteins. 98.8% is doing something else and they really don't know what the fuck it's doing! That's marvelous!

Great article, X!