Genetics is the study of genes, and studies what genes are and how they work. Genes are how living organisms inherit features from their ancestors; for example, children usually look like their parents because they have inherited their parents’ genes. 

Genetics tries to identify which features are inherited, and explain how these features are passed from generation to generation.

In genetics, a feature of a living thing is called a “trait”. Some traits are part of an organism’s physical appearance; such as a person’s eye-color, height or weight. Other sorts of traits are not easily seen and include blood types or resistance to diseases, these are also traits.

Genes are made from a long molecule called DNA, which is copied and inherited across generations. 

DNA is made of simple units that line up in a particular order within this large molecule. The order of these units carries genetic information, similar to how the order of letters on a page carries information. The language used by DNA is called the genetic code.

Genes are inherited as units, with two parents dividing out copies of their genes to their offspring (new born children).

You can think of this process like mixing two hands of cards, shuffling them, and then dealing them out again. Humans have two copies of each of their genes and when people reproduce they make copies of their genes and put them into eggs or sperm, When an egg of a female joins with a sperm of a male this gives a child a complete set of genes. 

This child will have the same number of genes as its parents, but for any gene one of their two copies will come from their father, and one from their mother.


Article taken from wikipedia.org