Somatic cell
Body cells that divide by mitosis, excluding germ and stem cells.
A somatic cell is any biological cell forming the body of a multicellular organism other than a gamete, germ cell, gametocyte, or undifferentiated stem cell. Somatic cells compose the body of an organism and divide through mitosis, making up all internal organs, skin, bones, blood, and connective tissue in mammals.
- type
- Biological cell
- function
- Forms body of multicellular organisms; divides via mitosis
- chromosomes_in_humans
- 46 (23 pairs)
- reproduction_role
- Not directly involved; mutations not passed to offspring
- cloning_method
- Somatic cell nuclear transfer
Lore & Background
Somatic cells derive from Ancient Greek σῶμα (sôma) 'body' and are also called vegetal cells. They are distinct from gametes, which derive from meiosis within germ cells and fuse during sexual reproduction. In mammals, somatic cells form all internal organs, skin, bones, blood, and connective tissue, while germ cells give rise to spermatozoa and ova. Theoretically, somatic cells transmit their mutations to cellular descendants but not to the organism's descendants, though in sponges non-differentiated somatic cells form the germ line, and in Cnidaria differentiated somatic cells are the source of the germline.
Reader's Guide
Somatic cells are central to understanding multicellularity, development, and aging. The evolution of an immortal germline producing specialized somatic cells involved the emergence of mortality, seen in its simplest version in volvocine algae. Species with separation between sterile somatic cells and a germline are called Weismannists, a relatively rare condition found in vertebrates, arthropods, and Volvox. Somatic cells contain DNA arranged in chromosomes; in humans, they contain 46 chromosomes organized into 23 pairs. The frequency of spontaneous mutations is significantly lower in advanced male germ cells than in somatic cells, reflecting more effective DNA repair mechanisms in germ cells. Somatic cells have been used in cloning via somatic cell nuclear transfer, as with Dolly the Sheep, and in biobanking for cryoconservation of animal genetic resources. Genetic engineering of somatic cells using TALENs or CRISPR has been supported by the International Summit on Human Gene Editing because modifications are not passed to offspring. Cellular aging in mammals is linked to reduced DNA repair capability in post-mitotic somatic cells such as those of brain and muscle.
Did You Know?
- Somatic cells divide through mitosis, while gametes derive from meiosis.
- In humans, somatic cells contain 46 chromosomes organized into 23 pairs.
- The frequency of spontaneous mutations is significantly lower in advanced male germ cells than in somatic cells from the same individual.
- Somatic cell nuclear transfer was used to clone Dolly the Sheep.
Frequently Asked Questions
How do somatic cells divide compared to germ cells?
Somatic cells reproduce through mitosis, producing two genetically identical daughter cells. This contrasts with germ cells, which undergo meiosis to halve their chromosome number for sexual reproduction.
How many chromosomes do human somatic cells carry?
Each human somatic cell contains 46 chromosomes arranged in 23 homologous pairs. This diploid set is what distinguishes them from haploid gametes, which carry only 23.
Why don't mutations in somatic cells get inherited by the next generation?
Because somatic cells sit outside the germline, any genetic changes they accumulate stay confined to that individual's body. Only mutations present in sperm or egg cells can be transmitted to offspring.
What's the connection between somatic cells and cloning?
Somatic cell nuclear transfer is the technique behind Dolly the sheep and other cloned mammals, where the nucleus of an adult body cell is transplanted into an enucleated egg to create a genetically identical copy. It essentially reprograms a differentiated somatic cell back into a totipotent state.
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