Autosomal Inheritance

Autosomal Inheritance

Autosomal inheritance refers to the inheritance of genes located on autosomal chromosomes, which are non-sex chromosomes (not X or Y).

Humans have 22 pairs of autosomal chromosomes (44 autosomes) in addition to the sex chromosomes (XX or XY).

Autosomal inheritance follows the principles of Mendelian genetics, as proposed by Gregor Mendel.

This means that traits are determined by alleles (variants of genes) on autosomal chromosomes, and they segregate and assort independently during gamete formation.

Autosomal traits can be influenced by dominant and recessive alleles.

Dominant alleles are expressed when present in one or two copies, while recessive alleles are expressed only when present in two copies (homozygous recessive).

Types of Inheritance Patterns:

a. Autosomal Dominant Inheritance:

- A single copy of the dominant allele is sufficient to express the trait.

- Affected individuals have at least one affected parent.

- Examples: Huntington's disease, Marfan syndrome.

b. Autosomal Recessive Inheritance:

- Two copies of the recessive allele (homozygous recessive) are required to express the trait.

- Parents are often carriers (heterozygous) without showing the trait.

- Examples: Cystic fibrosis, Tay-Sachs disease.

c. Autosomal Codominant Inheritance:

- Both alleles are fully expressed, and neither is dominant over the other.

- Examples: AB blood type, some forms of hereditary anemias.