Reproductive cloning is the cloning of a human being.

Another popular potential application of somatic-cell cloning concerns companion animals, particularly dogs and horses. Again, one will not get a phenotypic copy, so this only makes marginal sense. The resulting cloned animal will often have somewhat similar coat-color patterns and be roughly the same size, but it may have a very different personality, since this is largely influenced by environment. One does not recreate the same animal by cloning, simply a chromosomal genetic copy.

The biological definition of a genetic cloning

A cloned child may also feel obligated to follow the pre-determined path of their gene donor.

The biological definition of a genetic cloning - …

One other potential source of differences among animals cloned from genetically identical nuclei is cytoplasmic (see Figure 1) inheritance, illustrated most clearly by mitochondria. Mitochondria are small cytoplasmic bodies located in all cells (with hundreds per cell). They have numerous functions, including generation of energy for such life processes as muscular movement. Mitochondria have their own genetic information in the form of small, circular chromosomes. These almost always are inherited exclusively from mother via the oocyte. Different maternal lines have mitochondria of different genetic makeup, so it is the cytoplasm of the oocyte that determines the makeup of the mitochondrial genome, rather than the chromosomes in the nucleus. Thus, when cloning by nuclear transfer, the mitochondrial genetics will differ from clone to clone unless the oocytes are all derived from the same maternal line of females.

A biological definition of cloning | Motaxis

Another source of differences among clones is mutations in the DNA in nuclear chromosomes or mitochondria. DNA is composed of only four kinds of building blocks, known as adenine, thymine, guanine, and cytosine, or A, T, G, and C, respectively. The genetic makeup (DNA) of the nucleus of each mammalian diploid cell has around 12 billion of these building blocks, theoretically hooked together in precisely the same way when DNA is replicated, so that each daughter cell produced has the same genetic makeup, or order of the four building blocks as the "parent" cell that divided. As one might imagine, there is an occasional error when assembling 12 billion items in a specific sequence, and these errors are one source of mutations. Other causes of mutations include background radiation (with which we are constantly bombarded) and chemical reactions, such as peroxidation, which is a chemical process caused by oxygen that can be very detrimental.

Definition, Process and Genetic Engineering of E

The "gold standard" for genetic identity of mammals is identical twins, triplets, etc. These at least start out with identical chromosomal and mitochondrial genetics and are gestated in the same environment. Even postnatally, identical twins usually grow up in a very similar environment. All man-made clones will be less identical than these, especially in phenotype. Since there are considerable differences between naturally occurring identical twins, such differences will also occur among manufactured clones, in addition to the other differences already discussed.

Cloning - Biology-Online Dictionary

Clonal, or asexual, reproduction, in nature results in nearly genetically identical individuals. This includes two categories of genetic identity: between parent and offspring, and among offspring. However, for numerous traits, genetic identity does not result in phenotypic identity, either due to epigenetic effects or to environmental effects. The environmental effects are well known, particularly from human identical-twin studies. Epigenetic effects are defined as effects due to genes that vary from organism to organism due to random chance, and therefore, cannot ever be predicted exactly. Epigenetic effects are less well known than environmental effects, but can be huge for some traits, such as different coat-color patterns among clones or identical twins. There is no genetic instruction specifying the color of each individual hair in animals with hair of different colors, but only genetic instructions for the general pattern of hair color. These instructions provide general guidelines about how melanoblasts, which differentiate into cells termed melanocytes, migrate and invade hair follicles during fetal development, but not an instruction whether or not to invade an individual hair follicle. Melanocytes reside in hair follicles and add packets of melanin to color each hair as it grows. Numerous other epigenetic phenomena occur during embryonic and fetal development such as random X-chromosome inactivation in female mammals, different methylation (addition of a carbon atom plus 3 hydrogen atoms) patterns of cytosines (see below), and lengths of telomeres, which make up the ends of chromosomes.

Cloning humans? Biological, ethical, and social …

Recombinant DNA technology can also be applied to splicing genes into molecular devices that can transport these genes to various cellular destinations. This technique, also called gene therapy, has been used to deliver corrected genes into individuals who have defective genes that cause disease. Gene splicing has also been applied to the environment as well. Various bacteria have been genetically modified to produce proteins that break down harmful chemical contaminants such as DDT. Currently, scientists are investigating the application of this technology to produce genetically engineered plants and crops that can produce substances that kill insects. Similarly, fruits can be engineered to have genes that produce proteins that slow the ripening process in an effort to extend their shelf life.