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Scientific explanation In general, cloning means a method of producing organisms with identical sets of genes or identical genes. Many people are convinced that cloning was born with Dolly the sheep. On the contrary, vegetative reproduction of plants resulting in formation of clones is very common. Certain plants, at least in Europe, are in fact clones – e.g., Elodea and certain species of Reynoutria. In other plants vegetative reproduction is the most common way of reproduction - planting potatoes or dahlia tubers is an example. Cloning is also the routine method for molecular geneticists to produce many identical copies of a gene. Cloning of genes consists of insertion of a particular gene in plasmid, introduction of the latter in bacteria and cultivation of the bacteria to get great masses of cells. The cloned gene is then isolated from them in many copies. In animals the vegetative way of reproduction is regular in groups with simple body design (e.g. Coelenterata). In animals with more sophisticated body organisation such reproduction is not possible. However, identical copies are achieved by parthenogenesis. This means that the female reproductive cell – ovum – starts to develop without an involvement of a male cell (microspore, sperm). Therefore the resulting genome is a copy of the genome of the female only. Certain insects (Aphidae) reproduce by parthenogenesis during the most favourable part of the year and only before winter do they go through the sexual process. Certain fish (loaches) can also develop just from ovum without the involvement of sperm. In mammals natural reproduction is sexual, based on fusion of two haploid gametes forming in this way a diploid zygote where female and male genomes recombine. Therefore genome of offspring cannot be identical with either parent. In order to obtain identical copies the diploid nucleus carrying the genome of the “master” must be inserted in the oocyte. Naturally, the haploid nucleus is removed first. Cloning was not the aim in the experiment with the sheep Dolly. A transfer of nucleus from somatic cell in oocyte was performed to answer the question whether somatic cells contain the entire genetic information of the organism. The sheep Dolly was very apparent positive answer. However, in comparison with the vegetative reproduction or with parthenogenesis the nucleus transfer does not result in an individual with totally identical genetic background. Majority of genes are carried by the DNA in the cell nucleus, but not all of them. Eukaryotic cells contain organelles – mitochondria - most probably originating from symbiotic bacteria and generating energy by using oxygen for aerobic oxidation. They have their own DNA and genes and reproduce only through division of existing mitochondria because the mitochondrion cannot be formed from the information contained in the cell nucleus. Sperm does not inject own mitochondria in the ovum therefore offspring get mitochondria only from the mother. If an entire donor cell is transferred into an oocyte, its mitochondria do not survive. Thus, in order to get a totally identical clone, the oocyte and body cell nucleus must be from the same individual. Scientific reports recently suggest that oocyte can be developed in vitro from a stem cell. Based on this achievement of science we may speculate that in the future oocytes will be prepared from stem cells of the same individual playing the role of a nucleus donor. In such a case the resulting clone would be exactly identical, from the genetic point of view. Many pairs of twins originating from one zygote and therefore carrying identical genetic information were studied. It turns out that they are very alike but still differ in details as well as in their life history. This is because genes do not determine all features. They can be “switched on” and “switched off” in different ways due to external factors, they may be even “silenced” for a long time. Memory is one of features that are not encoded in genes. Instincts are different. Instincts are built-in in the structure of neuronal system formed during foetus development. Memory is created by gradual formation of new neuron connections as a result of learning. There are regions for various kinds of memory in the brain, e.g., memory for faces, for language, for motion activity such as walking, etc. Each newborn individual must form neuron connections the memory is based on. But it is also well documented that adult people who lose memory due to injury or stroke can resume it by learning. Therefore there is no scientific background for the statement that memory can be transferred by cloning.