If we made a sheep with blue fur using fish colour genes and then mated the sheep with a completely normal white sheep, what would happen? Would their offspring have blue, light blue or white fur?
What little googling I’ve done on sheep colors revealed that in sheep, the white gene is dominant. So if the fish genes were in the same location as the normal color genes, the offspring would probably be white, but carrying a recessive gene for the color.
If the fish genes were in a different location, it would depend on how the genes expressed. Could be blue, could be light blue; depending on whether the gene had dominance or incomplete dominance.
I’m wondering if there’s any chance of it being blotchy, blue and white. I don’t know what would cause that, but it would be cool looking.
More generally, it depends on the gene you’re fiddling with and exactly how it’s been fiddled - whether the trait is dominant or recessive and whether you’ve created a homozygote or heterozygote. About all we can say for sure is that it would be inherited like any other gene, and expressed according to how it works.
Let me expand on that. Smeghead’s right, it really does depend on what, exactly, we did.
First, we probably can’t just tweak one gene. Blue is a very “unnatural” color in animals and we probably don’t have it available with just a tiny tweak. Assuming we can do that, it depends on whether it’s Dominant or Recessive. It also depends on what genetic color-coding we have on the other sheep (IIRC, not all sheep are white).
If the Blue is Dominant, and White is also Dominant, and our sheep have Blue-Blue genes and White-White genes, we would end up with a lighter blue, although it would vary slightly in each individual offspring.
Or, if one is Recessive (and Blue would probably be Recessive), that gene would be masked, but could appear later as the genes spread throughout the herd.
Or, if it’s on the X chromosome, females will deactivate one of them at random and you could get the blotchy effect…
As I always like to say, in biology, if you can imagine it, there’s probably a mechanism by which it can happen, somewhere.
What?
Females have 2 X chromosomes. However, they only actually use one, the other is a Barr Body, and becomes deactivated. But a cell usually will randomly pick one of the two X’s to deactivate. So if the color WAS expressed on ONE X but not the other one, anytime that X was the one not deactivated the color would be expressed.
Hence the blotching effect- basically it’d be a marker showing you everywhere that your modified X was turned on, as the cells with that X active would produce the blue pigment. Wikipedia explains it a bit better than I can:
*
Since random chromosomes are selected for inactivation early in embryonic development, this results in different regions of the adult body having different chromosomes inactivated. This can be significant if different alleles of a gene are present on the different chromosomes; in some regions of the body one allele will be active, and in other regions the other will. This is what results in the coloration pattern of female calico cats; pigmentation genes on the X chromosome are activated in different patches of skin based on which chromosome is condensed in those regions (Alberts et al., 2002).*
That’s how you can get animals that are Calicos where one gene has one color being expressed while the other has another color being expressed, and depending on which Gene is turned on that’s what that cell/patch of skin will show.
Most of the fun genetic markers that biologists have been playing with for a long time, like green fluorescent protein and its relatives, count as dominant for genetic purposes. One copy is enough to produce the pigment. If you only inserted a single copy into your original cloned animal, half of its progeny would have the trait and the other half wouldn’t. It would only take a round or two of inbreeding to isolate an animal that was homozygous for your gene of choice.
Woot! Blue-sky-and-clouds sheep.
Good camouflage for hiding in trees.
“I bought some flowers for Alexandra.”
“Careful Bob; there’s treesheep around here.”
"Huh ?
“BAAAAA ! !”
< Sheep plunges from above >
- MUNCH *
“You woolly bastard ! Gimme those flowers back !”
Look at it this way. All breeds of dogs are the products of genetic modification via an old fashion method called breeding. So what happens you cross a beagle with a golden retriever? Dominant genes express themselves on the new pups. They look a bit like beagles and a bit like retrievers. The same thing happens when we use more sophisticated methods of genetic modification.
This type of inheritance is known as co-dominance, and is very common. Simple “Mendelian” dominant/recessive inheritance, which we frequently think of as the norm, is not that prevalent for many characters. Also, many characters are governed by a variety of different alleles, which can show complex dominance/recessive/partial dominance relationships.
This is great. I want to see this in a comic.
Boy meets Girl. Girl’s family are a pack of free spirited, homebrew biogen entrepreneurs. Oddness ensues.
Blood type and skin color - probably being the most common examples.