Somatic cell

Source: Wikipedia, the free encyclopedia.
See also: Somatic (biology)

In

Ancient Greek σῶμα (sôma) 'body'), or vegetal cell, is any biological cell forming the body of a multicellular organism other than a gamete, germ cell, gametocyte or undifferentiated stem cell.[1] Somatic cells compose the body of an organism and divide through mitosis
.

In contrast,

Stem cells also can divide through mitosis, but are different from somatic in that they differentiate
into diverse specialized cell types.

In

fertilization to produce a cell called a zygote, which divides and differentiates into the cells of an embryo. There are approximately 220 types of somatic cell in the human body.[1]

Theoretically, these cells are not germ cells (the source of gametes); they transmit their

diploid somatic cells. Only some cells like germ cells take part in reproduction.[2]

Evolution

As

invertebrates).[4][5]

Genetics and chromosomes

Like all cells, somatic cells contain

chromosomes organized into 23 pairs. By contrast, gametes of diploid organisms contain only half as many chromosomes. In humans, this is 23 unpaired chromosomes. When two gametes (i.e. a spermatozoon and an ovum) meet during conception, they fuse together, creating a zygote
. Due to the fusion of the two gametes, a human zygote contains 46 chromosomes (i.e. 23 pairs).

A large number of

hexaploid"). Thus, they can have diploid or even triploid germline cells. An example of this is the modern cultivated species of wheat, Triticum aestivum L., a hexaploid species whose somatic cells contain six copies of every chromatid
.

The frequency of spontaneous mutations is significantly lower in advanced male germ cells than in somatic cell types from the same individual.[6] Female germ cells also show a mutation frequency that is lower than that in corresponding somatic cells and similar to that in male germ cells.[7] These findings appear to reflect employment of more effective mechanisms to limit the initial occurrence of spontaneous mutations in germ cells than in somatic cells. Such mechanisms likely include elevated levels of DNA repair enzymes that ameliorate most potentially mutagenic DNA damages.[7]

Cloning

Schematic model of somatic cell nuclear transfer. This technique has been used to create clones of an organism or in therapeutic medicine.

In recent years, the technique of

Dolly the Sheep (July 5, 1996 - February 14, 2003)[9] and, more recently, Snuppy (April 24, 2005 - May 2015), the first cloned dog.[10]

Biobanking

Somatic cells have also been collected in the practice of biobanking. The cryoconservation of animal genetic resources is a means of conserving animal genetic material in response to decreasing ecological biodiversity.[11] As populations of living organisms fall so does their genetic diversity. This places species long-term survivability at risk. Biobanking aims to preserve biologically viable cells through long-term storage for later use. Somatic cells have been stored with the hopes that they can be reprogrammed into induced pluripotent stem cells (iPSCs), which can then differentiate into viable reproductive cells.[12]

Genetic modifications

Schematic of CRISPR based gene editing technique

Development of biotechnology has allowed for the genetic manipulation of somatic cells, whether for the modelling of chronic disease or for the prevention of malaise conditions.[13][14] Two current means of gene editing are the use of transcription activator-like effector nucleases (TALENs) or clustered regularly interspaced short palindromic repeats (CRISPR).

Genetic engineering of somatic cells has resulted in some

controversies[citation needed], although the International Summit on Human Gene Editing has released a statement in support of genetic modification of somatic cells, as the modifications thereof are not passed on to offspring.[15]

See also

References

  1. ^
    ISBN 978-0-8053-6844-4
    .
  2. doi:10.4095/315247
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  3. PMID 21174128
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  4. ^ Ridley M (2004) Evolution, 3rd edition. Blackwell Publishing, p. 29-297.
  5. ^ Niklas, K. J. (2014) The evolutionary-developmental origins of multicellularity.
  6. PMID 9707592
    .
  7. ^
    PMID 23153565
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  8. PMID 26416677
    .
  9. ^ "The Life of Dolly | Dolly the Sheep". Retrieved 2023-12-09.
  10. PMID 29127382
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  11. PMID 35928671
    .
  12. PMID 36210477
    .
  13. PMID 28300165
    .
  14. ^ "NIH Commits $190M to Somatic Gene-Editing Tools/Tech Research". 24 January 2018. Retrieved 5 July 2018.
  15. ^ "Why Treat Gene Editing Differently In Two Types Of Human Cells?". 8 December 2015. Retrieved 5 July 2018.
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