Amitosis is a method of cell division

Introduction to the information contained in this article will allow the reader to learn about one of the ways of cell division - amitose. We will clarify the features of the process, consider differences from other types of division and much more.

What is amitosis?

Amitosis is a cell division of a direct type. This process is due to the usual division of the nucleus into two parts. However, it may miss the phase of spindle formation for division. A ligation occurs without condensation of chromatin. Amitosis is a process peculiar to cells of animals and plants, as well as to the simplest organisms.

From history and research

Robert Remak in 1841 described the process of amitosis for the first time, but the term itself arose much later. Already in 1882 histologist and biologist of German origin Walter Flemming proposed the modern name of the process itself. Amytosis cells in nature is relatively rare, but often it can occur, since it is necessary.

Process Features

How does the division of cells? Amitosis often occurs in cells that have a decreased mitotic activity. Thus, a lot of cells that must die as a result of old age or changes in pathological nature, can delay their demise for a while.

Amitosis is a process in which the state of the nucleus retains its morphological features during the interphase period: the nucleolus is perfectly visible, like its envelope, DNA is not replicated, chromatin is protein, DNA and RNA are not spiraled, and there is no identification of chromosomes in the nucleus of the eukaryotic cell.

There is an indirect division of the cell - mitosis. Amitosis, unlike it, allows the cell to keep its activity as a functioning element after division. Finger spindle (structure designed for chromosomal segregation) is not formed with amitosis, but the nucleus is still divided, and the consequence of this process is the random distribution of hereditary information. The absence of a cytokinetic process results in the reproduction of cells with two nuclei, which in the future will not be able to enter into a typical cycle of mitosis. Multiple repetition of amitosis can lead to the formation of cells with multiple nuclei.

Current situation

Amitosis as a concept began to appear in a variety of textbooks back in the 80's of the twentieth century. To date, there are suggestions that all the processes that were previously put under this concept are in fact misinterpreted results of studies on poorly prepared micropreparations. Scientists believe that the phenomenon of cell division, accompanied by the destruction of the latter, could lead to the same misunderstood and interpreted data. However, some processes of fission of eukaryotic cells can not be attributed to either mitosis or meiosis. A vivid example and confirmation of this is the process of dividing the macronucleus (the nucleus of the ciliate of the infusoria, large in size), during which the segregation of certain chromosome regions occurs, in spite of the fact that the spindle is not formed for division.

What causes the complication of studying the processes of amitosis? The fact is that this phenomenon is difficult to determine from its morphological features. Such a definition is unreliable. The inability to clearly identify signs of morphology amitosis process is based on the fact that not every nuclear constriction is a sign of amitosis itself. And even the dumbbell form, which is clearly expressed in the nucleus, can only refer to a rolling type. Also, constrictions of the nucleus can be the result of errors in the phenomenon of the preceding division by mitosis. Most often, amitosis occurs immediately after endomitosis (a method of doubling the chromosome number without dividing both the cell and its nucleus). Usually, the process of amitosis leads to a doubling of the cell nucleus. Repeating this phenomenon creates a cell with a lot of cores. Thus, amitosis creates cells with a chromosomal set of polyploid type.

Conclusion

Summing up, we can say that amitosis is a process during which the cell is divided by a direct type, that is, the nucleus divides into two parts. The process itself is not capable of providing cell division into equal, identical halves. This also applies to information about heredity of the cell.

This process has a number of sharp differences from the stage-by-stage division by mitosis. The main difference in the processes of amitosis and mitosis is the absence of destruction of the shell of the nucleus and the nucleolus with amitosis, as well as the course of the process without the formation of a spindle, which ensures the division of information. Cytotomy in most cases is not divided.

Currently there are no studies of the modern era, which could clearly distinguish amitosis as a form of cell degeneration. The same applies to the perception of amitosis as a method of cell division due to the very small amount of division of the whole cell body. Therefore, amitosis may be better attributed to the regulatory process that takes place inside the cells.