Re: Is it okay to clone endandgered species so you can take them off the list?

That’s a very interesting question. Lets take a look at some of the issues at stake so that you can get some ideas for your project.

First off, what does it mean for a species to be on the endangered species list? Well, according to the 1973 Endangered Species Act, an endangered species is "any species which is in danger of extinction throughout all or a significant portion of its range…." with the exception of insect pests. (Apparently, it is OK to let insect species go extinct if we don’t like them.)

So, both species which are only found in captivity, as well as species which can be found in their natural habitiats, but are still in danger of being rendered extinct, are considered endangered.

Now, when we clone an organism (because we can’t clone a species), we are creating new members of the species that are genetically identical (see below), to the organism that we selected to clone. So, on the one hand, we are (in theory) increasing the number of different members of the species, but on the other hand, we are creating a species of genetically identical individuals.

Now, we have to consider what happens to these clones after we have created them in the laboratory. If we let them grow to adult-hood in captivity, then there is little chance that they will be able to survive in the wild, and the species to which they belong will still be endangered, because even though the clones are living happily in the lab, the rest of the species is still out in its range, in danger of extinction.

If we release the clones into the wild (assuming they can survive if we release them), we have to consider a number of additional factors. First of all, is the species endangered because its habitat is shrinking? If that is the case, then it seems likely that the clones will compete with the other non-cloned members of the species for limited resources; the result could be even worse than the situation prior to cloning.

A second issue we have to consider is the genetic diversity of the pre- cloning endangered species. As we release greater and greater numbers of clones into the wild, the chance increases that matings will occur between genetically identical individuals. Although born in the wild, the offspring of these clone-clone matings will have many more genes in common than the offspring of two non-cloned, wild parents. The result is that the population will become increasingly inbred, or genetically homogenous, over time.

In general, inbreeding is considered a bad thing for a number of reasons. First of all, inbreeding increases the chance that your offspring will inherit deleterious genetic defects, resulting in deformations or inborn genetic diseases. For example, Cheetahs are thought to be an extremely inbred species, and all Cheetahs have asymmetrically deformed heads; sharing the same deformation.

In addition (at least for vertebrate animals), as a population becomes increasingly inbred, it loses the ability to deal effectively with new pathogens. This is because a given population of vertebrate animals has a large number of different versions (alleles) of the genes that your immune system uses to detect and respond to pathogens like bacteria and viruses. These genes are called Major Histocompatibility Complex (MHC) genes. While any given individual has only 2 copies of a particular MHC gene, the population has many different versions of this gene, and the different versions can detect different bacteria and viruses. If a population becomes homogenous, then everyone will have the same versions of these MHC genes, and the population will only be able to defend against a few bacteria or viruses. That means that if the population encounters a new pathogen, the whole population will be susceptible to the disease, and the whole population could be wiped out.

So, to get back on track, the less diverse a given wild population is when you start to make clones of members of that population, the faster the new population will become inbred. Since we are talking about making clones from endangered species, we know that the populations are already into the low numbers; in many cases, endangered species have been reduced to a handful of individuals. Even if you were to clone each member of the population, quite a lot of the genetic diversity of the species would have been lost.

Now, lets see if I can sum up the points raised here. (1) Cloning organisms and keeping the clones in captivity really contributes nothing towards taking a species off of the endangered species list. If that organism’s habitat is being destroyed, the best thing to do is to try and save, reclaim and expand the habitat so that the species can expand into its old range naturally. (2) Cloned organisms reduce the genetic diversity of the species and bring with them the potential for extreme inbreeding, which can generally have very bad results. In general, it seems like captive breeding programs have experienced quite a lot of success in increasing the size of endangered populations, while maintaining the population’s level of genetic diversity.

I guess my answer is, "No. It is not Okay." ;)

I hope this helps with your project!

A Caveat to Cloning

The cloning of animals doesn’t necessarily result in an organism which is genetically identical to the organism that we selected to clone. Animal, Plant and Fungal cells keep their genetic material in more than one place in the cell. When we clone animals, we are really just cloning the nucleus, which contains most of the cell’s DNA. The cytoplasm of animals also contains mitochondria, which contain their own DNA. When a clone is created by inserting the nucleus of an adult cell into an anucleated ovum, the organism that results will have the nuclear DNA of the organism that was selected to clone, but the mitochondrial DNA of the organism that donated an ovum to the whole process.