What are genes?
Genes are what determine your traits, such as eye color and blood type. They are located
in your chromosomes. We normally have 23 pairs or 46 total chromosomes in each cell
of our bodies. There are an estimated 20,000-25,000 different genes contained on these
chromosomes. Genes are made of DNA.
Genes are found in pairs, just as the chromosomes are. One member of each gene pair
is inherited from your mother. The corresponding member of the gene pair is inherited
from your father. Genes are expressed in different ways. For some genes, both copies
are needed in order for the protein they make to work properly in the body. For other
genes, only one copy is necessary. For yet other genes, how the gene works depends
on which parent it was inherited from.
Genes that are present on the first 22 pairs of chromosomes are said to be autosomal.
This means that both males and females are equally likely to have these genes. The
last pair of chromosomes determines gender. Males have one X and one Y chromosome,
while females have two X chromosomes. Therefore, females do not have any of the genes
present on the Y, and males have only one copy of genes on the X.
The idea of inheritance was first described by Austrian monk Gregor Mendel during
the mid-19th century. Mendel performed experiments on garden peas in order to figure
out patterns of inheritance. These basic patterns are sometimes called Mendelian or
The basic patterns of inheritance are:
There are many different single gene defects that need clinical care by a healthcare
provider. We have provided a brief overview for some, which are listed below.
Autosomal Dominant Inheritance
Autosomal Recessive Inheritance