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Related to tetrad: Tetrad analysis


1. a group or series of four
2. the number four
3. Botany a group of four cells formed by meiosis from one diploid cell
4. Genetics a four-stranded structure, formed during the pachytene stage of meiosis, consisting of paired homologous chromosomes that have each divided into two chromatids
5. Chem an element, atom, group, or ion with a valency of four
6. Ecology a square of 2 × 2 km used in distribution mapping



(1) A group of four haploid cells formed by meiosis from a single diploid cell. Tetrads are typical of plants. In mosses, fungi, and algae, such four-celled groups may remain for a long time within the membrane of the parent cell. By isolating the cells of the tetrad in these organisms, vegetative offspring may be obtained and the genetic division in each meiosis may be studied by means of tetrad analysis. Ordered arrangements of cells may occur in tetrads; the chromosome groups in the cells of such tetrads reflect the order in which the chromosomes of two successive meioses separate. These cells, called linear asci, are typical of some ascomycete fungi.

(2) In tetrad analysis, the four cultures obtained by the vegetative propagation of spores formed after the meiosis of a single diploid cell.

(3) A structure composed of four connected chromatids. It is observed in animal cells during the prophase of the first, or reductive, division of meiosis. Such tetrads are also called bivalents.



(cell and molecular biology)
A group of four chromatids lying parallel to each other as a result of the longitudinal division of each of a pair of homologous chromosomes during the pachytene and later stages of the prophase of meiosis.
References in periodicals archive ?
The Tetrad features a modular design, and can be disassembled easily, allowing for module replacement without the need to return the device to our facilities for repair, should the unit become damaged.
Here's a dark thought: Do be vigilant about family members and friends showing signs of trolling and the Dark Tetrad.
He said he wants to shake up the industry, and it is for this reason that Tetrad won't be employing anyone with previous recruitment experience.
10 Sarcina bacteria can be differentiated from Staphylococcus species, even though both organisms are gram positive, because Staphylococcus bacteria, at approximately 1 [micro]m in diameter, is much smaller and is arranged in characteristic grapelike clusters, rather than a tetrad pattern.
McLuhan's tetrad can be a useful tool for making meaning from the apparently chaotic signals.
May 4 ~ May 7###Microspore tetrad stage###Inner and outer integument initiation to elongation
The tetrad is an analytical model created by McLuhan to facilitate the translation of user experiences of media.
In 1493, a tetrad saw the expulsion of Jews by the Catholic Spanish Inquisition.
It's not just evangelical Christians, messianic Jews and Hebrew roots believers touting something big, something significant in the tetrad of blood moons set for a grand finale "supermoon" show on September 28.
This Shemitah of Shemitahs has also had a Tetrad of four Blood Moons all occurring on Jewish feast days, which has not happened in 2,000 years
Therefore, Hegel's dialectical triad thesis-antithesis-synthesis is extended to the neutrosophic tetrad thesis-antithesis-neutrothesis-neutrosynthesis.