the four homologous chromatids in a bundle during the prophase and metaphase of meiosis
Source: Jenkins, John B. 1990. Human Genetics, 2nd Edition. New York: Harper & Row ...
Groups of four. At metaphase of meiosis, chromosomes are grouped in pairs. We can therefore count four chromatids. This is why this arrangement is called a .
View Dr Chromo's lecture on 'Meiosis'.
Related Links ...
A method for establishing linkage relationships in fungi by analysing the four products from individual meiotic divisions.
The four products of a single meiosis.
[Gk. tetras, four]
In genetics, a pair of homologous chromosomes that have replicated and come together in prophase I of meiosis; consists of four chromatids.
tetrad The four chromatids in each cluster during synapsis; formed by the two sister chromatids in each of the two homologous chromosomes. PICTURE ...
The four haploid cells formed at the end of meiosis. The term was formerly used for the four chromatids making up a chromosome-pair at the first division of meiosis.
tetrad A pair of homologous chromosomes during synapsis (prophase I of meiosis). A tetrad consists of four chromatids.
tetrapods A nontaxonomic designation used to refer to amphibians, reptiles, birds, and mammals.
Each is comprised of four chromotids - the two homologs, each with their sister chromatid
Homologous chromosomes will swap genetic material in a process known as crossing over (abbreviated as XO) ...
Bivalents (tetrads) become aligned in the center of the cell and are attached to spindle fibers.
The chromosome alignment illustrated below is from a cell with a diploid chromosome number of 8.
In reality, however, the number is doubled, since each chromosome consists of four granules grouped to form a .
Result: a tetrad. (These structures are sometimes referred to as bivalents because at this stage you cannot distinguish the individual sister chromatids under the microscope.)
The two homologous dyads are held together by ...
This may occur if chromosomes do not separate properly during meiosis I.
Alternatively, sister chromatids may fail to separate during meiosis II.
The alleles on this tetrad:
will produce the following chromosomes if there is a crossing-over event between the 2nd and 3rd chromosomes from the top: ...
Recent advances, including whole-genome sequencing efforts, chromatin immunoprecipitation using kinetochore proteins, and analysis in the model plant Arabidopsis thaliana, ...
Prophase I: Homologous chromosomes pair up and form tetrads. This pairing is known as synapsis. While paired, the homologous chromosomes exchange genetic material in a process called crossing over.
:30 This is the first point in meiosis where the four parts of the s are actually visible. Sites of crossing over entangle together, effectively overlapping, making chiasmata clearly visible.
Some of these Hsp100 chaperones, like ClpA and ClpX, associate with the double-ringed tetradecameric serine protease ClpP; instead of catalyzing the refolding of client proteins, ...
metaphase I the phase during meiosis in which s align on the equatorial plate (as in mitosis).
metaphase II the phase during meiosis II in which the chromatid pairs gather at the center of the cell prior to separation.
A pair of Staphylococcus aureus have gone through 2 cell divisions, producing a pair of tetrads. Cell division in this and other bacteria can occur every 20 to 30 minutes. Elsewhere on this site, you can learn about the dynamics of bacterial growth.
In fungi, a sac that encloses a or an octad of ascospores. The sac in Ascomycete fungi that holds the ascospores.
Bivalent a pair of homologous chromosomes during meiosis‚ also known as a tetrad
(bi = two; valent = strength)
Blastocyst the hollow ball stage of embryonic development
(blasto = bud‚ sprout) ...
bivalent /BUY-vale-É™nt/ n. A pair of synapsed homologous chromosomes; this configration occurs during meiotic prophase I. Also known as a "." ...
AP-1 is actually a complex between c-fos protein and c-jun protein, or sometimes is just c-jun dimers. The AP-1 site consensus sequence is (C/G)TGACT(C/A)A. Also known as the TPA-response element (TRE). [TPA is a phorbol ester, tetradecanoyl phorbol ...
See also: Cells, Chromosome, Cell, Human, Animal