«Soma" means a body, that is, in theory, any cell of the body should be called somatic.However, directories provide a different definition.In fact, the somatic cells in the majority, but in the body, there are other kinds of them.
First of all, nesomaticheskie - are cells that later turn into an embryo.They share a special way, not typical for somatic cells (meiosis) and a few other features.More recently, scientists have discovered a new class of cells that is neither sex nor somatic.They are called stem, and one can turn any cell of the body.
somatic vertebrate cells form bone, internal organs, skin, blood and connective tissue.A germ cells become sperm and eggs.Unlike germ cells, somatic have a double set of special structures for heredity - chromosome.
All somatic cells are a heritage from the two organisms, one half of the chromosomes is almost identical to the mother of our individual chromosomes, and the second - chromosomes father.We used the word "almost" because every body throughout life undergoes a process of mutation, that is unplanned and primed in the genes change.Mutation of somatic cells is not as serious as mutations in the germ.Because in the latter case, a whole new body will carry the following changes (which in most cases are not desirable for the body, beneficial mutations - a huge rarity).
general somatic cells do not always have only two sets of chromosomes.The plants can be as many as four or six pairs of sets.Appropriate sex cells are 2-3 set, which is understandable.For example, wheat they may be four or six (depending on species).In some instances, the somatic animal cells also have more than two sets, such as the case with salmon and salamander.
Sometimes too many sets of chromosomes (polyploid) happens in humans, it may be the result of the process of mitosis or meiosis of the first phase.In the first case, it is not terrible - it turns out only a few abnormal body cells, but if polyploid becomes a sex cell, then it is doomed because during fertilization inevitable very serious violations of the whole organism (if still a cell formed zygote, embryo dies).Still not normal for higher polyploid species.
Sometimes polyploid, not inherent in the normal one or another form (usually plants), appears after the use of certain chemicals, which is an additional argument for having to tighten environmental controls.
division of somatic cells creates cells that are identical to the parent if the process is normal and there was no violations occurred, provoked by external and internal factors.The process of cell division is called mitosis such a long time and studied by scientists.This division is stable and reliable, but in general, mitosis makes no progress - because the cells are obtained exactly as they gave birth to a cell.But there are sex cells of another organism and form entirely new cells, which will be a unique body and continue the evolutionary struggle.
there any way to get a body that would not be genetically different from the parent?Yes, this is called cloning.The technique is simple in theory - take the nucleus of a somatic cell into an egg and carefully tended, planted instead of "native" core.This is not necessary to fertilize an egg and implanting in the uterus can be a female.However imperfect technology, moreover, the resulting body gets sick and can not live long.So no wonder prohibited human cloning.
Thus, somatic cells make up a large part of our body are divided by mitosis and have two chromosome sets.This is the main thing to know about this species cells.
