What’s the point of cloning?

Answer

Hi Erwin,

A clone is, strictly speaking, a genetically identical copy. For example, identical twins are basically clones of each other because they are genetically identical. Even when you take a graft from a plant, the mother plant and the graft are genetically identical and therefore clones. In principle, these types of clones are not much different from clones that were made in the lab, of which Dolly the sheep is the best known example.

However, living organisms are more than just their DNA. There are indeed environmental influences. A plant that grows up in a sunny environment with lots of fertilizers and sufficient sunlight will undoubtedly differ greatly from its clone that grows up in a saline soil with little sunlight and few nutrients. In twins, the skin of the brother or sister who grew up near the equator will be noticeably darker than that of the brother or sister who lives in the far north.

In addition, two genetically identical plants in the same flower box will also be different. This is because the genotype (a difficult word for the genetic material) and the phenotype (the external characteristics) are not linked in a one-to-one relationship. Thus chance has a strong determining factor in the process of the development of an organism. And for those who do not believe in chance, these chance factors can probably always be reduced to environmental factors. For example, a difference in one or a few proteins during development can cause a certain gene to be expressed more or less. This can then have a cascade of other consequences, ultimately determining why one twin is an inch taller than his or her sibling.

If we now discuss the word “cloning” a little further, we should mention that making identical organisms (type Dolly) is only one interpretation of the word. In biological, biotechnological and biomedical research, the word is also used to denote the making of genetically modified organisms or DNA elements by making copies of genes. For example, many clones have already been cloned with the gene for Green Fluorescent Protein (GFP). This GFP gene was initially taken from a jellyfish and then cloned into bacteria, yeast, worms, insects, mice and even monkeys. This is to illustrate that when cloning you do not immediately have to think of duplicating organisms (Dolly and associates) but also of duplicating separate genes.

Now, what’s the point of cloning then?

The clearest is the second interpretation I gave of the word “cloning”. Researchers who want to study a specific gene or gene product (a protein) prefer to do so in an organism that is as simple as possible. Cloning a gene in a bacterium takes a week’s work, putting a gene in a mouse often takes several years. When a mouse gene has been introduced into a bacterium, it is therefore much easier to study. 99% of cloning work is this kind of cloning.

The cloning of entire organisms also has its reasons. For example, this may be because a number of phenotypic traits are in a one-to-one relationship with their genotype. Consider, for example, the blood group or immunological characteristics. One could think of cloning people because the clone would then be the perfect match as a stem cell or organ donor, for example. Or a bull that produces superior seed for cattle breeding could be cloned towards the end of its life to fertilize the next generation of cows with that valuable seed.

Conclusion:
Making 100% phenotypically identical organisms is impossible because there is no one-to-one relationship between the DNA and the external characteristics.

Regards,
Benjamin