Mosaic (genetics)

Overview of genetic mosaicism

For the art form, see Mosaic.

Mosaicism in Genetics

A tulip displaying mosaicism, with variegated colors.

Mosaicism in genetics refers to the presence of two or more populations of cells with different genotypes in one individual who has developed from a single fertilized egg. This condition can affect any type of cell, including somatic and germ cells.

Causes of Mosaicism

Mosaicism arises from mutations that occur in a cell during development after fertilization. These mutations can be caused by various factors, including errors in DNA replication, environmental influences, or spontaneous mutations.

Somatic Mosaicism

Somatic mosaicism occurs when the mutation arises in a somatic cell, which can lead to a patchy distribution of the mutation throughout the body. This type of mosaicism can result in conditions such as cancer or neurofibromatosis.

Germline Mosaicism

Germline mosaicism occurs when the mutation is present in the germ cells, which can be passed on to offspring. This can result in a child being affected by a genetic disorder even if the parents do not show any symptoms.

Examples of Mosaicism

Close-up of a tulip petal showing mosaic patterns.

One of the most well-known examples of mosaicism is the variegated coloring seen in some plants, such as the tulip shown in the image. In humans, mosaicism can manifest in various ways, including skin pigmentation disorders like vitiligo or mosaic Down syndrome.

Detection and Diagnosis

Mosaicism can be detected through various genetic testing methods, including karyotyping, fluorescence in situ hybridization (FISH), and next-generation sequencing. These tests can identify the presence of different genetic populations within an individual.

Implications of Mosaicism

The presence of mosaicism can have significant implications for genetic counseling and disease prognosis. It can affect the severity and presentation of genetic disorders and influence the risk of passing on genetic conditions to offspring.

Related pages

• Genetic disorder
• Mutation
• Chromosomal mosaicism
• Chimera (genetics)