List I | List II | ||
---|---|---|---|
A | Mesozoic Era | I | Lower invertebrates |
B | Proterozoic Era | II | Fish & Amphibia |
C | Cenozoic Era | III | Birds & Reptiles |
D | Paleozoic Era | IV | Mammals |
The process of generating a genetically identical copy of a cell or an organism is known as cloning. Cloning takes place all the time in nature—for instance when a cell replicates itself asexually without any genetic alteration or recombination. Prokaryotic organisms (organisms short of a cell nucleus) like as bacteria create genetically identical duplicates of themselves and make use of binary fission or budding. In eukaryotic organisms (organisms holding a cell nucleus) like humans, all the cells that go through mitosis, such as skin cells and cells lining the gastrointestinal tract, are clones; the only special cases are gametes (eggs and sperm), which go thruogh meiosis and genetic recombination.
Read More: DNA Cloning