Cloning
in nature occurs more than most people may imagine and when people think
about cloning an image from a movie or remembering the famous sheep named
Dolly may come to mind. Aside from the movies and media cloning in nature
takes place every day. There are several plant species, animals, and
bacteria that produce a product known as a clone. A clone is an exact
genetic replica of an
organism. These clones are produced through
asexual reproduction. Starfish for example, can regenerate a whole new organism
from a single severed appendage. Then there are
flat worms that can be divided
in two and regenerate to form two flat worms. Many other species on our planet
are able to produce a clone of itself. Some of these clones are much more
abundant than others and you may be able to see one or many of them in your
everyday life. (Robinson 101)
Asexual reproduction
occurs with only one organism. Asexual reproduction is not as commonly
known as sexual reproduction where two organisms interact to reproduce.
Asexual reproduction is a single cell dividing to form two daughter cells
that are genetically identical to the parent cell. This process is called
fission. Fission can either be binary, where two cells are produced, or by
multiple fission where many new
cells are created. (Knight 135)Three events
must take place for this duplication: the deoxyribonucleic acid DNA, which
makes up the individual chromosomes within the cell’s nucleus must be
duplicated; the two sets of DNA must be packaged up into separate nuclei;
and the cell’s cytoplasm must divide itself to create two separate cells,
each complete with its own nucleus.(Wilmoth 103)
A large advantage of asexual reproduction in nature is that an organism can reproduce quickly without having to find a mate or wait for pollination and colonize an area that is favorable to its environment. Some bacteria can double their numbers in 20 minutes! (Knight 135)
In plants, apomixis is the technical term used for asexual reproduction. The term apomixis is derived from apo meaning, “without,” mixis meaning “mingling.” So apomixis refers to the fact that asexual reproduction lacks the mixing of genes that occurs in sexual reproduction. (Robinson 18)
Apomixis in plants is
separated into two types: vegetative reproduction and agamospermy. Vegetative
reproduction is when part of a plant can be separated from the parent plant by
growing roots with contact to soil and also having other
characteristics
from plant growth.(Appropriate water, light, and gaseous exchange.) Poplar
trees are an example of a plant that performs vegetative reproduction. By
cutting off a branch from a poplar tree and placing it into the ground you have
created a clone of the parent tree. Agamospermy is when the plant can produce a
seed without pollination. A mango is one of many tropical fruits that reproduce
this way. (Robinson 18)
In the
farming industry vegetative propagation is used for crops like potatoes,
raspberries, bananas and pineapples. Like the poplar tree, these crops
reproduce by forming growths, called runners which grow horizontally and
generate new stalks. At some point, the runner decomposes, leaving a new plant
that is a
clone of the original. This helps farmers with their crops because some plants
are difficult to cultivate from seed and the vegetative propagation of those
plants makes it possible to grow crops that otherwise would not be available for
commercial marketing. (Knight 136)
Cloning in nature may show a way of survival. Clonal groups are known in true aspens where the group size can cover large areas. Because of this tightly kept group that covers large areas many believe that this clonal habit has allowed the aspens, whose individual trees are short-lived, to survive in the drier parts of the Rocky Mountains. The current climate in the Rocky Mountains does not allow germination of aspen seeds or survival of germinants, the present clonal groups might be over 8,000 years old, and may have germinated in a period when the climate was more humid.(Heybroek 277)
Advantages of asexual reproduction would be that an individual reaching a new area can always reproduce, despite other plants of that specie being present. Asexual reproduction also means that a plant’s offspring will share 100 percent of its genes, while sexually produced offspring share only 50 percent of their genes with each parent. The main disadvantage of asexual reproduction is lack of genetic variation. For example, a disease or pest that may directly affect that specific plant would have a good chance of eliminating the entire species in a given area. Asexual reproduction has also been described as an evolutionary dead-end because plants that only reproduce asexually cannot combine genes to produce new genetic variants. If there is a climate change that plant species would not be able to evolve enough to tolerate the new conditions it is living in. (Robinson 19)
Cloning is much more present than most people imagine. It is not only a movie sci-fi, thrill or something that takes place in a laboratory. Cloning in nature happens every day whether it is the duplication of seeds, fungi or bacteria. So next time you see a certain tree, fruit, worm or maybe even a starfish, hopefully you remember the possibilities and ways it may have been created.