Skip to main content

Germ Cells and the Germ Cell Line

Germ Cells and the Germ Cell Line

Germ cells are one of two fundamental cell types in the human body. Germ cells are responsible for the production of sex cells or gametes (in humans, ovum and spermatozoa). Germ cells also constitute a cell line through which genes are passed from generation to generation.

The vast majority of cells in the body are somatic cells. Indeed, the term somatic cell encompasses all of the differentiated cell types, (e.g., vascular, muscular, cardiac, etc.) In addition, somatic cells may also contain undifferentiated stem cells (cells that, with regard to differentiation are still multipotential). Regardless, while the mechanism of genetic replication and cell division is via mitosis in somatic cells, in germ cells a series of meiotic divisions during gametogenesis produces male and female gametes (i.e., ovum and spermatozoa that upon fusion (fertilization) are capable of creating a new organism (i.e., a single-celled zygote).

While somatic cell divisions via mitosis maintain a diploid chromosomal content in the daughter cells produced, germ cellsin contrastthrough a series of mitotic divisions produce haploid gametes (i.e., cells with one-half the normal chromosome compliment sone autosomal chromosome from each homologous pair and a sex chromosome (X in females, X or Y).

Although all humans start out as single-celled zygotes, the germ cells for each individual are set aside early in embryogenesis (development). If the cells comprising the germ cell line are subject to mutation or other impairments, those mutations may be passed down to offspring. It is from the germ cell line that all spermatogonia and all oogonia are derived.

While controversial because of ethical considerations, both germ cells and stem cell research focus on the pluripotent potential of these cells (i.e., their ability to differentiate into cells found in various tissues of the body). Embryonic stem cells are derived from the inner cell mass of human blastocysts, embryonic germ cells can be obtained from the primordial germ cells located in the gonadal folds, ridge, and surrounding mesenchymal cells of fetal tissue during the middle of the first trimester of development (e.g., four to nine weeks).

Recent research using extracted embryonic germ cells grown in culture over twenty generations showed that the cells had the ability to differentiate in all three fundamental embryonic tissue types (ectoderm, meso-derm, and endoderm).

See also Cell division; Embryo and embryonic development; Embryo transfer; Embryology; Meiosis; Mitosis.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"Germ Cells and the Germ Cell Line." The Gale Encyclopedia of Science. . Encyclopedia.com. 20 Nov. 2018 <https://www.encyclopedia.com>.

"Germ Cells and the Germ Cell Line." The Gale Encyclopedia of Science. . Encyclopedia.com. (November 20, 2018). https://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/germ-cells-and-germ-cell-line

"Germ Cells and the Germ Cell Line." The Gale Encyclopedia of Science. . Retrieved November 20, 2018 from Encyclopedia.com: https://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/germ-cells-and-germ-cell-line

Learn more about citation styles

Citation styles

Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

Modern Language Association

http://www.mla.org/style

The Chicago Manual of Style

http://www.chicagomanualofstyle.org/tools_citationguide.html

American Psychological Association

http://apastyle.apa.org/

Notes:
  • Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most Encyclopedia.com content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
  • In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.