An autosome is any chromosome that is not a sex chromosome. Humans have 22 pairs of autosomes and one pair of sex chromosomes (XX or XY). Autosomes are numbered 1-22 and are associated with various metabolic functions of the body.
What is Autosome?
An autosome is a chromosome that is not involved in sex determination. Humans have 23 pairs of chromosomes, with one pair being the sex chromosomes (XX or XY) and the other 22 pairs being autosomes.
Autosomes are numbered roughly in relation to their sizes, with chromosome 1 being the largest and chromosome 22 being the smallest. The members of an autosome pair in a diploid cell have the same morphology, unlike those in autosomal (sex chromosome) pairs, which may have different structures.
Autosomes control the inheritance of all an organism’s characteristics except for sex-linked ones, which are controlled by the sex chromosomes.
Autosomal genetic disorders can arise due to a number of causes, some of the most common being nondisjunction in parental germ cells or Mendelian inheritance of deleterious alleles from parents.
Numerical abnormalities in autosomes generally result from meiotic nondisjunction – that is, unequal division of chromosomes between daughter cells – that can occur during either maternal or paternal gamete formation.
An autosome is any chromosome that is not a sex chromosome. Humans have 22 pairs of autosomes and one pair of sex chromosomes. Autosomes control all inherited characteristics except for sex-linked ones.
Autosomal genetic disorders can arise due to various causes such as meiotic nondisjunction or Mendelian inheritance.
Function of Autosomes
Autosomes are any chromosome that is not a sex chromosome. Humans have 22 pairs of autosomes, which are labeled with numbers (1-22) roughly in order of their sizes in base pairs.
Autosomes control the inheritance of all an organism’s characteristics except the sex-linked ones, which are controlled by the sex chromosomes. The DNA in autosomes is collectively known as atDNA or auDNA.
Genes in autosomes function as the coding instructions for proteins, which are used to create every cell, enzyme, tissue, bone, and organ within an organism. Autosomes still contain sexual determination genes even though they are not sex chromosomes.
For example, the SRY gene on the Y chromosome encodes the transcription factor TDF and is vital for male sex determination during development. TDF functions by activating the SOX9 gene on chromosome 17. Mutations of the SOX9 gene can cause humans with an ordinary Y chromosome to develop as females.
Examples of Autosomal Disorders
Examples of autosomal dominant disorders include Huntington’s disease and Marfan syndrome. On the other hand, autosomal recessive disorders occur when a person inherits two copies of the mutated gene, one from each parent.
Examples of autosomal recessive disorders include cystic fibrosis, sickle cell anemia, and Tay-Sachs disease.
Cystic fibrosis is a common inherited single-gene disorder that affects a protein responsible for producing mucus, sweat, and digestive juices. Sickle cell anemia is a blood disorder that causes red blood cells to become misshapen and break down prematurely.
Tay-Sachs disease is a rare inherited disorder that progressively destroys nerve cells in the brain and spinal cord. Huntington’s disease is an inherited disorder that causes progressive degeneration of nerve cells in the brain. Marfan syndrome is a genetic disorder that affects connective tissue throughout the body.
These are just some examples of autosomal disorders. There are many other types of genetic disorders caused by mutations in genes located on autosomes. Genetic counseling can help individuals understand their risk of inheriting or passing on an autosomal disorder.
what is the difference between autosomal dominant and autosomal recessive disorders?
Autosomal dominant and autosomal recessive disorders are two types of genetic disorders that differ in the way they are inherited.
Autosomal dominant disorders occur when a single copy of the mutated gene is enough to cause the disorder, while autosomal recessive disorders require two copies of the mutated gene (one from each parent) to cause the disorder.
In autosomal dominant inheritance, a child has a 50% chance of inheriting the condition if one parent has an altered gene. Examples of autosomal dominant disorders include Huntington’s disease, Marfan syndrome, and achondroplasia.
On the other hand, in autosomal recessive inheritance, both parents must carry an altered copy of the gene for their child to inherit the condition.
The parents themselves do not show any symptoms because they have only one altered copy of the gene. Examples of autosomal recessive disorders include cystic fibrosis and sickle cell anemia.
Autosomal dominant and autosomal recessive disorders differ in how many copies of an altered gene are required to cause a genetic disorder. In autosomal dominant inheritance, one altered copy is enough to cause a disorder while in autosomal recessive inheritance, both copies must be altered.
how many copies of the mutated gene are required for autosomal dominant disorders?
Autosomal dominant disorders occur when only one altered copy of an autosomal gene is required to cause the disease. This means that if a person has one altered copy of the gene in each cell, they will be affected by the disorder.
In some cases, an affected person inherits the condition from an affected parent. In others, the condition may result from a new variant in the gene and occur in people with no history of the disorder in their family.
Autosomal dominant disorders affect males and females equally since they involve autosomes or non-sex chromosomes.
Many autosomal dominant disorder mutations arise de novo, or for the first time within a family, in an individual due to sporadic mutation in parental gonads or within the developing fetus.