The Food & Drug Administration is expected to give the green light to meat and dairy products produced from cloned animals. It is no surprise that biotech boosters like my friend Ronald Bailey cheer this development. Perhaps a bit more surprising is today's endorsement of cloned meat from the Washington Post. Even though polls suggest public unease with the idea of cloned meat, the Post applauds the FDA's focus on the scientific evidence showing the safety meat and dairy products from cloned animals.
Cloning animals with superior genetics will make animal products better and less expensive. Breeders aim to grow genetic twins of animals with desirable traits -- such as leaner, tastier meat -- in order to breed them and improve herds over generations. The only difference between this technique and traditional animal husbandry is the production of a genetic copy at the outset. As more high-quality breeding stock becomes available, the value of such animals will decrease, lowering production costs. Americans who don't want to eat animal products made this way will undoubtedly have the opportunity to do so through niche producers.
Related Posts (on one page):
- Cloned Bull:
- Clone Meat and Milk "OK"; No Need to Label:
- "Clone on the Range":
how do you improve your stock by cloning? Wouldn't you be getting more of the same quality stock instead of improving it?
I'm probably missing something, but that was the first thing I thought of
Is it possible that this risk might reduce or eliminate the economic benefits?
But I still don't get why people think this is a great idea. There are many easier and cheaper ways to make meat leaner, and the meat industry wouldn't be waiting for cloning to do so if it really believed that customers want leaner steak.
Would you also require that naturally bred, viable offspring of cloned animals be labeled this way? and for how many generations? (I don't disagree with labeling per se, but would limit it to the actual animal)
Why would a cloned herd be more susceptible to disease? To the contrary, I would think that higher than average disease resistance might be one trait for which animals might be selected as cloning candidates. I can't see why cloning would necessarily increase the risk of disease at all.
-dk
Think of it as being similar to the practice of artificially inseminating farm animals. Artificial insemination and cloning have the similar advantages and disadvantages. They allow wide dissemination of valuable genotypes but tend to reduce genetic variation within the stock.
Oh give me a clone
Of my own flesh and bone,
With its Y chromosome changed to X;
And when it is grown,
Then my own little clone
Will be of the opposite sex.
[Chorus:]
Clone, clone of my own,
With its Y chromosome changed to X!
And when I'm alone
With my own little clone,
We will both think of nothing but sex.
But why should such sex vex,
Or perturb or perplex,
Or induce a disparaging moan?
For it's plain, can't you see,
That it's just me and me,
So when we're making love, I'm alone.
[Repeat chorus]
I don't know. Just a conjecture. My impression is that, while some disease resistance can be bred for, the emergence of an unexpected threat would be much more dangerous to a cloned herd than a non-cloned one.
I could be all wrong.
Most biologists believe that sexual reproduction is evolutionarily stable despite the fact that that the energy invested in male tissue is in some sense wasted because it enhances parasite resistence. In species where the males never fight over mates the males are often substantially smaller than the females to solve the problem of the wasted male biomass.
[As an amusing aside ... from the weight and strength ratio of human males and females you would expect males who achieve reproductive success to have about four or five mates -- and those religions that do allow polygamy usually settle on about this size for the harems.]
-dk
Isn't that a contradiction?
Thanks.
No, I think you're right; I wasn't thinking of evolved or unforeseen diseases, but it makes sense that shrinking the genetic diversity of the population would increase its vulnerability to species-specific pathogens, as Dick King points out.
Nick P,
On the other hand, SuperBull is going to pass only 50% of its genotype to its offspring, and there's no telling how the genes that are transmitted might interact with genes from the female (perhaps SuperBullery genes are recessive and therefore not expressed when mom's MediocreCow genes are present). Cloning is less risky since at least in theory you're guaranteed to get an identical copy of the cloned organism (though, not being an expert on this by any means, I would imagine there's still the possiblity of random mutation that would prevent the cloned organism from being an exact copy of the original).
The economic advantages will show up as cloning becomes more affordable and stable. Granted, I dont know how much stud fees are, but I do know that, if I were a rancher who did'nt own a superbull, buying one load and having it cloned might be cheaper than buying a load for all my cows.
Is that legal in many states?
I wondered the same thing about armies.
Well, obviously by the time of Episode IV, the stormtroopers can't shoot straight worth a damn ...
As James said, Superbull semen gives you calves with only 50% of his characteristics. It takes several generations to fully upgrade a herd. OTOH, if you clone Supercow and breed the clones with Superbull semen, you get a herd of Supercalves in just two generations.
Considering the expense and difficulty of cloning, I think this is the plan. The clones themselves won't go on the meat shelves except as low-grade hamburger when they're too old to breed, and (if the results are as hoped for) their children will also be far more valuable as breeding stock than as meat or milk cows.
I believe caution is indicated in the above scenario due to the Inbreeding Coefficient gradually increasing, which could accentuate desirable traits, but also non-desirable traits. This would be especially true when a substantial percentage of the herd is a clone of the same cow or bull. Of course, there is something to be said for maintaining a level of hybrid vigor in herd or flock. Yes, there’s more of a chance for unexpected results in the way of offspring productivity, but sometimes an “outcross is desirable when inbreeding coefficient increase, which can result in problems.
Right now the prohibitive factor for the producer in cloning is cost. I believe that will result in bulls being initially cloned, as semen can be sold throughout an already established marketing channel (e.g. Semex, ABS Global), and have the ability to build sire and dam proofs in a more timely manner (for more info see the following presentation by USDA AIPL staff). To clone a cow would take longer to establish more reliable proof data, and I believe it would require an embryo transfer procedure, which itself is an expensive procedure.
As to the previous comments on disease, it is possible that a disease would be more problematic for animals that share traits of a specific genotype. As an example, much work has been done in this area in regards to Scrapie, a TSE similar to “mad-cow disease” that affects sheep and goats. Research has established that sheep have a greater susceptibility and resistance to scrapie based on specific genotypes. Through this work, animals are selected based on the presence of these desirable genotypes, while less desirable genotypes are eventually culled from the flock.
Although the science of livestock genetics is first rate, this does not mean that sound genetic practices improperly implemented or science that cannot detect problems until after the fact is not an issue, and will continue to be an issue. For example, even with the advances in dairy cattle genetics, problems have cropped up in the 25 years such as decreased pregnancy rates, clearly something that was not expected. If genetic science cannot detect this flaw until years after the fact, and a single bull or family of bulls is responsible for this problem, and said bull is cloned, the impact would be even more wide ranging. Sometimes, too much of a good thing is not good in the long run.
If this cloning works out at all, I expect that in the long run they'll do what seed companies have been doing for a long time: keep two or more lines of purebred stock carefully isolated to protect them from disease, and hybridize two lines to get the premium beef cattle, selling the hybrid calves off as soon as they are weaned to farmers who will raise them for slaughter. The hybrids won't breed true, but they are intended for eating, not breeding. This is an advantage for the breeders - the farmers at the end of the chain have to keep coming back for more stock, so it works only if the hybrids are sufficiently better than a non-hybrid breed to make up for the extra cost.
It would be a bit more difficult to do this for dairy cows...
I'm not worried about being attacked by frankenfood, but I'm curious on the producer side, just how far this has gone for large-scale production. Last I heard they were dealing with the problems that clones were aging faster than regular animals. I didn't recall much about offspring of clones. How many generations have they done? Do the offspring age normally? Have they solved the aging problems in clones?
That's the theory. I don't know whether it's been confirmed in practice. And there's the possibility that the cloning process actually damaged the DNA in ways that haven't been detected yet but can be passed on. (IIRC, it takes tens or hundreds of attempts to get one live-born clone; if all the others were damaged fatally, what does that say about the chance of a hidden defect in the survivor?)
This all seems to me rather like speculating about how 500-passenger transatlantic airliners will work in 1905.
[1] This "molecular clock", which might be better described as a counter, apparently evolved as a barrier to cancer. Most normal cells can only divide a certain number of times. If a cell mutates so that it ignores the signals that tell it that no more growth is required, it will divide rapidly and form a tumor, but without also hitting upon a way to reset the counter it will eventually hit the limit and stop growing. A side effect of this clock is that the body will eventually be unable to replace skin and blood cells and will die of "old age". It's better than dying much younger of cancer...
Obviously, germ cells in the ovaries and testicles must be exempt from this, perhaps by continually setting the counter back to zero. So maybe there is a genuine question as to whether a clone's germ cells get this ability restored, but I expect that it's the environment that enables it, not something actually carried in the DNA.