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Blood Group of the child, the inheritance of the blood group of the child

 

In the beginning of the last century, scientists proved the existence of 4 groups of blood. How are inherited by child blood group?

The Austrian scientist Karl Landsteiner, mixing the serum of some people with red blood cells taken from the blood of others, found that for certain combinations of red blood cells and serum is “bonding” – the clumping of red blood cells and clots, while others have not.

Exploring the structure of red blood cells, Landsteiner discovered the particular substance. He divided them into two categories, A and b, highlighting the third, where he carried the cage in which they were not. Later, his disciples – A. von Decastella and A. Storli – found cells containing the markers and type at the same time.

The studies have any system of division into groups of blood, which was called AVO. This system we still use today.

I ( 0 ) – blood group is characterized by the absence of antigens A and b;

II ( A) is installed in the presence of antigen A;

III ( AB ) – antigen;

IV( AB ) – antigens A and B.

This discovery made it possible to avoid losses if transfusions caused by incompatibility between the blood of patients and donors. First successful transfusion was carried out before. So, in the history of medicine of the nineteenth century described a successful blood transfusion for the mother. Having received a quarter of a liter of blood, according to her, she felt, “like life itself penetrates her body”.

But before the end of the twentieth century such manipulations were isolated and were conducted only in cases of emergency, at times bringing more harm than good. But thanks to the discoveries of the Austrian scientists blood transfusions have become much more safe procedure that helped to save many lives.

System AV0 turned scientists ‘ ideas about the properties of blood. Further study of geneticists. They proved that the principles of inheritance of the blood group of the child are the same as for other signs. These laws were formulated in the second half of the nineteenth century, Mendel, on the basis of experiments with peas have been familiar to us for textbooks biology.

Blood group of the child

Inheritance of blood group of the child according to the law of Mendel

According to Mendel, the parents with the I blood group, will produce children that do not have antigens A – and b-type.

The couple with I and II – children with matching blood groups. The same situation is characteristic of the I and III groups.

People with IV group can have children with any blood type except for I, regardless of, what type of antigens are present in their partner.

The most unpredictable inheritance of a child of blood group at the Union of owners with the II and III groups. Their children may have any of the four blood groups with equal probability.

The exception is the so-called “Bombay phenomenon”. Some people are present in the phenotype A and b antigens, but do not manifest phenotypically. However, this is extremely rare, and mostly Indians, for which it received its name.

The inheritance of the RH factor

The birth of a child with a negative rhesus factor in the family with RH – positive parents in the best case causes deep confusion, in the worst – distrust. The accusations and doubts about the loyalty of his wife. Oddly enough, nothing exceptional in this situation. There is a simple explanation for such a delicate problem.

RH factor is a lipoprotein located on the membranes of red blood cells in 85% of people ( they are considered RH-positive ). In his absence they say about RH-negative blood. These indices are denoted by Latin letters Rh with the sign “plus” or “minus” respectively. For the study of rhesus typically consider a single pair of genes.

Positive RH factor is denoted by DD or Dd and is a dominant trait, and negative – dd, recessive. At the Union of people with heterozygous presence of RH ( Dd ) in their children will be RH positive in 75% of cases and negative in the remaining 25%.

Parents: Dd x Dd. Children: DD, Dd, dd. Heterozygosity occurs as a result of the birth of a rhesus-conflict child in RH-negative mother, or may be stored in the genes for many generations.

The inheritance of characteristics

For centuries parents just wondered what would be their child. Today we have a glimpse into the glorious future. Thanks to ultrasound to know the sex and some features of the anatomy and physiology of the infant.

Genetics helps to identify possible eye color and hair, and even the presence of the musical ear of the baby. All these features are inherited according to Mendel, and are divided into dominant and recessive. Brown eye color, hair with small curls and even the ability to roll the tongue into a tube are dominant traits. Most likely, the child will inherit.

Unfortunately, the dominant characteristics are the tendency to early baldness and graying, short-sightedness and a gap between his front teeth.

To recessive consider gray and blue eyes, straight hair, light skin, a mediocre musical ear. Having these symptoms less likely.

Boy or …

For many centuries in a row the blame for the lack of an heir in the family had placed on the woman. To achieve the goal – the birth of the boy – women resorted to diets and calculated auspicious days for conception. But look at the problem from the point of view of science. The sex cells ( eggs and sperm ) have a half-set of chromosomes ( i.e. 23 ). 22 of them are identical in men and women. Differs only in the last couple. In women it is the chromosomes XX and males XY.

So the probability of birth of a child of either gender is entirely dependent on the chromosomes of the sperm were able to fertilize the egg. Simply put, the sex of the child is fully responsible … dad!