tetrad

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Related to Tetrads: meiosis

tetrad

 [tet´rad]
a group of four similar or related entities, as (1) any element or radical having a valence, or combining power, of four; (2) a group of four chromosomal elements formed in the pachytene stage of the first meiotic prophase; (3) a square of cells produced by division into two planes of certain cocci (Sarcina).

tet·rad

(tet'rad),
1. A collection of four things having something in common, such as a deformity with four features, for example, Fallot tetralogy. Synonym(s): tetralogy
2. In chemistry, a quadrivalent element.
3. In heredity, a bivalent chromosome that divides into four chromatids during meiosis.
[G. tetras (tetrad-), the number four]

tetrad

/tet·rad/ (tet´rad) a group of four similar or related entities, as (1) any element or radical having a valence, or combining power, of four; (2) a group of four chromosomal elements formed in the pachytene stage of the first meiotic prophase; (3) a square of cells produced by division into two planes of certain cocci (Sarcina) .
Fallot's tetrad  tetralogy of Fallot.

tetrad

(tĕt′răd′)
n.
1. A group or set of four.
2. A tetravalent atom, radical, or element.
3. Biology
a. A four-part structure that forms during the prophase of meiosis and consists of two homologous chromosomes, each composed of two sister chromatids.
b. A group of four haploid cells, such as spores, formed by meiotic division of one mother cell.

te·trad′ic adj.

tetrad

[tet′rad]
Etymology: Gk, tetra, four
a group of four chromatids of a synapsed pair of homologous chromosomes during the first meiotic prophase of gametogenesis. The group is formed in preparation for the two meiotic divisions in the maturation of gametes. tetradic, adj.

tet·rad

(tet'rad)
1. A group of four things having something in common, such as a deformity with four features, e.g., Fallot tetralogy.
Synonym(s): tetralogy.
2. chemistry A quadrivalent element.
3. genetics A bivalent chromosome that divides into four during meiosis.
[G. tetras (tetrad-), the number four]

tetrad

  1. the four homologous CHROMATIDS which associate during prophase (the PACHYTEN stage) and metaphase of MEIOSIS and are involved in CROSSING OVER.
  2. the four haploid cells produced by one complete meiotic division.

tet·rad

(tet'rad)
Collection of four things having something in common, such as a deformity with four features, e.g., tetralogy of Fallot.
[G. tetras (tetrad-), the number four]

tetrad

a group of four similar or related entities, as (1) any element or radical having a valence, or combining power, of four; (2) a group of four chromosomal elements formed in the pachytene stage of the first meiotic prophase; (3) a square of cells produced by division into two planes of certain cocci (sarcina).
References in periodicals archive ?
In 1493, a tetrad saw the expulsion of Jews by the Catholic Spanish Inquisition.
A detailed developmental study at ultrastructural level of Anaxagorea brevipes (Annonaceae) showed that the parietal tapetum reluctantly invades the locule at the early tetrad stage and secretes both orbicules and other globular lipoidal concretions (Gabarayeva, 1995).
These incredible pictures captured the drama of the blood moon eclipse - the first of a series known as a tetrad.
There are 1,796 tetrads across North Wales - every one was visited for this project.
During periods when many tetrads occur there are also many ITLEs.
Although the first cytokinesis did not occur at the correct time, it occurred simultaneously with the second cytokinesis after telophase II, generating normal tetrads.
The wall-bearing tapetum phase was ended at the tetrad developmental stage and Tapetum cells started breaking down prior to anther dehiscence, which was according to findings of Murgia et al.
Because of pancytopenia (Table), a bone marrow biopsy was performed and showed intraerythrocytic ring forms with tetrads.
After this initial period, monads, dyads and tetrads without envelopes appeared and were followed by free hilate monads and trilete spores.
Tetrads certainly help sort things like this out in a hurry, don't they?