lampbrush chromosome

lamp·brush chro·mo·some

, lamp-brush chromosome

1. a large chromosome found in oocytes of certain animals characterized by many fine lateral projections giving the appearance of a test tube brush or lampbrush.

2. multiply looped chromosomal area of the chromatin of some species.

Synonym(s): giant chromosome (2)

lampbrush chromosome

(lămp′brŭsh′)

n.

A large chromosome found especially in the immature eggs of amphibians, consisting of two long strands that form many brushlike loops along the main axis of the chromosome.

lampbrush chromosome

Etymology: Gk, lampas, torch; AS, bryst, bristle

an excessively large type of chromosome found in the oocytes of many animals. It has long, threadlike, projecting loops, giving it a hairy, brushlike appearance. See also giant chromosome.

chromosome

in animal cells, a structure in the nucleus, containing a linear thread of deoxyribonucleic acid (DNA), which transmits genetic information and is associated with ribonucleic acid and histones.

During cell division the material composing the chromosome is compactly coiled, making it visible with appropriate staining and permitting its movement in the cell with minimal entanglement. Each organism of a species is normally characterized by the same number of chromosomes in its somatic cells. The diploid numbers (number of total chromosomes per cell) are cattle—60, sheep—54, horse—64, donkey—62, pig—38, dog—78, cat—38, human—46. The chromosomes are arranged in pairs and one of the pairs is the sex chromosomes (XX or XY), which determines the sex of the organism. See also heredity.

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compound chromosome

a genetic engineering procedure which produces two chromosomes in one of which the left arms of the two original chromosomes are joined together and the two original right arms are also joined together; used in genetic control of insect populations.

homologous c's

the chromosomes of a matching pair in the diploid complement that contain alleles of specific genes.

lampbrush chromosome

so named because of the bristling appearance given them by many open loops of chromatin along the extended chromosome.

ring chromosome

a chromosome in which both ends have been lost (deletion) and the two broken ends have reunited to form a ring-shaped figure.

sex c's

the chromosomes responsible for determination of the sex of the individual that develops from a zygote, in mammals constituting an unequal pair, the X and the Y chromosome.

somatic chromosome

autosome.

submetacentric chromosome

see submetacentric.

W chromosome

sex chromosome in animals such as poultry in which the female is the heterogametic state, the male has the ZZ genotype and the female the ZW genotype.

X chromosome

the female sex chromosome, being carried by half the male gametes and all female gametes; female diploid cells have two X chromosomes, the male has the XY genotype.

Y chromosome

the male sex chromosome, being carried by half the male gametes and none of the female gametes; male diploid cells have an X and a Y chromosome; females carry the XX genotype.

Z chromosome

sex chromosome in animals, such as poultry, in which the female is the heterogametic sex; the male has the ZZ genotype and the female the ZW genotype.