With current technology, the prerequisite for cloning is to obtain healthy and complete living cells. So, where to get healthy and complete living cells? In fact, our common samples can be divided into three categories according to whether they can be used for cloning and how difficult they are.
1. The first category, hair, remains and dander commonly seen in criminal investigation drama.
There is no doubt that there is absolutely no problem with using these items for paternity testing or identity tracing. Since they are from the body, certainly they store the owner's DNA information, which can be obtained through scientific means. However, these cells have died and lost their viability, which is contrary to the requirement of "healthy and complete living cells" required by the current cloning technology. Therefore, these samples are not available for cloning at present. However, biotechnology is advancing by leaps and bounds, and perhaps these materials can also be used for cloning in the near future.
In addition, there is a special existence among them - although hair cannot be used for cloning temporarily, the newly plucked hair usually has hair follicles, and the somatic cells on fresh hair follicles can be used for cloning.
2. Here we will introduce the second type of common samples, blood, oral mucosa, and urine!
Yep, that is right! The urine we excrete contains not only urea and water, but also active cells carrying DNA, which sufficiently can be used for cloning! This is because in the process of formation and excretion, urine will be excreted from the body together with the somatic cells shed from the body, and these somatic cells are still complete, fresh and warm. While the blood carries white blood cells and red blood cells. Among them, white blood cells can be used for cloning because it contains complete active DNA, but red blood cells cannot be used for cloning because they do not have a nucleus. Needless to say, oral mucosa, everyone in junior high school biology class has observed his own oral mucosa cells with a microscope. They are also complete and active somatic cells.
Although these DNA carriers can be used for cloning, the number of active somatic cells they contain is very small. Due to the low efficiency and low success rate of cloning, these DNA carriers are usually rarely used for cloning.
3. In fact, the most ideal cloning material is the third type, that is, somatic cells.
However, there are many classifications of animal tissues and organs. In some tissues, the genome changes during cell development, so not every somatic cell is suitable for cloning.
For example, the B cells and T cells of the immune system, whose genomes are rearranged during the maturation process, tending to produce immune-deficient individuals if used as donors to clone animals; What's more, muscle cells are familiar to everyone, and the mature muscle cells are multinucleated cells. However, it will fail to reconstruct embryo due to multinucleation. For another example, sperm and eggs contain only half of chromosomes and do not carry complete DNA information.
In addition, there are many tissues in which cells culture is difficult and cannot be successfully established. Therefore, skin cells are the most suitable clone donor cells in consideration of multiple aspects such as genome, cell structure and culture difficulty.