Genetic Basic concepts

What are Chromosomes - Chromosomes are the structures in which our hereditary material (DNA) is packed. A healthy person has 46 chromosomes (23 pairs). One chromosome of each pair (i.e. a total of 23 chromosomes) is donated by each parent to the fetus ...

Our Genes - DNA - This is the hereditary material of man and all other life forms. It exists in all the cells of the body and encodes all human properties. Most of the DNA is concentrated in the cell nucleus and organized in bodies known as chromosomes...

Mode of Inheritance

Autosomal dominant - In autosomal dominant inheritance, a single copy of an abnormal gene is enough for clinical signs of the disease to appear. This is because both the healthy gene and the abnormal gene are equally active. In this inheritance pattern, both males and...

Autosomal recessive - When a person is a "carrier" of an inherited disease, he has one normal gene and one abnormal gene for the condition. In autosomal recessive inheritance, the action of the healthy gene predominates over that of the abnormal gene. This means that a ...

X- linked - This inheritance pattern only refers to genes that are present on the X chromosome. Females have two X chromosomes and males have one X and one Y chromosome. This is the reason why a male who carries an abnormal gene on his single X chromosome...

Mitochondrial - Every cell contains organelles known as mitochondria. These are responsible for important cellular activities, of which production of energy for the cell is the main one. Each cell has on average 100 mitochondria. Most of the cell's genetic ...

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