Genetics

Genes are what makes an individual to be built with two blue eyes, two arms, one nose, and a brain with certain architecture. Genes are segments of our DNA and the units of our inheritance. A gene consists of four chemical molecules: adenine, cytosine, guanine, thymine (ACGT). The short chemical name for a chain of any number of these molecules, is DNA.

• The order that these molecules are in determines the instructions for everything the cell does, much like how the order of letters in written language determine the meaning of the sentence.

The job of genes is to make proteins, the building blocks of life.

Every living thing uses the same genetic code, meaning we can transfer a single human gene into a cat, and the cat can read it and follow its instructions

Genotype: the set of genes that an animal has in its body

Phenotype: the manifestation of those genes, such as what color fur it has, what type of food it eats, etc.

Epigenetics

Every cell within an animal body is of the same genome. That is, each cell has the same set of genes as all the other cells. At the same time, we have different types of cells in the body. Liver cells are different from brain cells are different from the stomach cells. The reason for this is epigenetics. The cells in the stomach are the same as the cells in the brain, but in the stomach, a different set of genes are activated than are activated in the brain cells.

• it is possible that the "activation of certain subsets of cells" is an inheritable trait by the offspring. However, if this is the case, it would only be passed on to the immediate offspring. It would not travel further down the line of descendants.