Sister chromatids are identical copies of a chromosome. Compare sister chromatids to homologous chromosomes, which are the two different copies of the same chromosome that diploid organisms (like humans) inherit, one from each parent.
sister chromatids - two identical copies of a parent chromosome which are attached to one another at the centromere.
somatic cell - any cell in the body that is not a germ cell (reproductive cell).
sister chromatids Chromatids joined by a common centromere and carrying identical genetic information (unless crossing-over has occurred). PICTURE ...
Sister chromatids that stain differently, so that one appears dark and the other light (harlequin-like).
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z ...
Compare: sister chromatids.
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How do nonsister chromatids ensure that crossing over between them will occur without the loss or gain of a single nucleotide? One plausible mechanism for which there is considerable laboratory evidence postulates the following events.
Anaphase is characterized by two distinct processes to separate the sister chromatids and move them to opposite spindle poles in preparation for cell division.
During metaphase, cohesion between sister chromatids is maintained by a chromosomal protein complex, cohesin. Anaphase is triggered when separase cleaves the Scc1 subunit of cohesin at two specific recognition sequences.
Anaphase is preceded by metaphase, by the end of which fully condensed sister chromatids are arranged in pairs, their centromeres lying along a surface known as the metaphase plate.
Centromere: Constricted region where sister chromatids are attached in mitotic chromosomes. The centromere is generally flanked by repetitive DNA sequences and it is late to replicate. The centromere is an A-T region of about 130 bp.
A cross-over between strands of two non-sister chromatids during recombination. The junction where two homologous chromosomes appear to exchange genetic material during recombination. (Chi is the greek letter c which resembles a genetic cross-over.) ...
Anaphase I: Chiasmata break apart and sister chromatids begin migrating toward opposite poles.
Telophase I: CLEAVAGE FURROW forms beginning the process of CYTOKINESIS (cell division). Resulting daughter cells are HAPLOID (1N).
crossing over between sister chromatids either on the same or on homologous chromosomes
Source: Jenkins, John B. 1990. Human Genetics, 2nd Edition. New York: Harper & Row
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sister chromatid One of the two identical parts of a duplicated chromosome in a eukaryotic cell. Sister chromatids consist of exact copies of a long coiled DNA molecule with associated proteins.
Centromere the central region of a chromosome which holds the sister chromatids together
(centro = center; mer = part)
Cerebellum the wrinkled-looking‚ posterior part of the brain
(cereb = the brain; -elle = small) ...
The reciprocal exchange of genetic material between nonsister chromatids during synapsis of meiosis I.
cryptic coloration
(krip-tik)
A type of camouflage that makes potential prey difficult to spot against its background.
crossing over
the reciprocal exchange of genetic material between non-sister chromatids during synapsis of meiosis I.
Crustacea
class in the phylum Arthropoda. Most members of this class are aquatic, although a few are terrestrial.
centromere A specialized region on each chromatid to which kinetochores and sister chromatids attach. PICTURE
cephalization The concentration of sensory tissues in the anterior part of the body (head).
Sister chromatid exchange A crossover between sister chromatids (chromatids which are the products of replication of a single chromosome and which ought therefore to be genetically identical).
During cell division, the chromosomes first replicate so that each daughter cell receives a complete set of chromosomes. Following DNA replication, the chromosome consists of two identical structures called sister chromatids, ...
 See also: Chromatid, Sister chromatid, Chromosome, Chromosomes, Cell
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