Genetics Basic Concepts


Cloning means creating genetically identical copies of a living being or of one of its parts. In other words, clones share the same genetic material. Scientists remove the nucleus from a cell that belongs to the individual living being they wish to clone. The nucleus is where your find the DNA molecules that contain genes. This nucleus is then transferred to an egg whose own nucleus has been removed. From this artificially made cell, an embryo will develop and grow into an individual that is genetically identical to the original. 

In Canada, cloning human beings is prohibited. Under the Assisted Human Reproduction Act, this ban applies to human clones for both reproductive and therapeutic purposes. 

It is interesting to note that cloning happens in nature too. All single-cell organisms, such as bacteria, reproduce by making a copy of themselves during cellular division. 

Identical twins are also a kind of natural clone! In fact, monozygotic twins (born from the same egg) have the same genetic make-up.

In some species, the females can lay eggs that do not need to be fertilized by males. Yet, they contain chicks. This is known as parthenogenesis, another form of natural cloning. Individuals born from asexual reproduction are genetically identical to their biological mothers and do not have a biological father. Many vertebrate species are capable of reproducing through parthenogenesis. These include certain sharks, amphibians, reptiles and birds. Whiptail lizards are a female-only species that reproduce solely through parthenogenesis. 

Certain plants, too, propagate by producing special structures (e.g., bublets, stolons, rhizomes, etc.). These types of reproduction in plants are actually a form of cloning. When gardening, we also take part in plant cloning. For instance, plant cutting is used to grow individuals using a piece of the plant, such as a leaf, stem, root, etc. Layering involves taking an aerial stem and putting it in contact with damp soil to get a new root to grow. A stem or branch is partially buried where it will develop a new system of roots independent from the parent plant. This type of propagation in plants is considered asexual reproduction. Unlike sexual reproduction, which requires the fusion of gametes (e.g., sperm and egg), asexual reproduction is the capacity to reproduce without a partner.