polyteny

pol·y·tene

P0431400 (pŏl′ē-tēn′)adj. Relating to or having large chromosomes formed by repeated DNA replication and consisting of many chromatids side by side.

[poly- + Latin taenia, band (from Greek tainiā, ribbon; see ten- in Indo-European roots).]

pol′y·te′nic adj.pol′y·te′ny n.

polyteny

(ˈpɒlɪˌtiːnɪ) n (Biology) biology the condition of being polytene

Polyteny

the presence in the nucleus of certain somatic cells of giant multifilamentous (polytene) chromosomes, which are hundreds of times larger than normal chromosomes. Polyteny leads to substantial increase in ploidy of the nuclei (up to 32.768N in Chironomus). Polyteny was first described in 1881 by the French cytologist E. Balbiani. Polytene chromosomes are observed in the cells of larvae of a number of Diptera (Chironomus, Drosophila), in Protozoa, and in some plant cells. Polyteny is the result of repeated replications of chromosomes without subsequent divsion of the cell or its nucleus. Giant chromosomes are characterized by specificity of location of the cross-bands, which permits compilation of chromosome maps and study of the functional activities of each band or group of bands.

REFERENCES

Lobashev, M. E. Genetika, 2nd ed. Leningrad, 1967. Swanson, C, T. Merz, and W. Young. Tsitogenetika. Moscow, 1969. (Translated from English.)

M. M. ASLANIAN

单词	polyteny
释义	polyteny pol·y·tene P0431400 (pŏl′ē-tēn′)adj. Relating to or having large chromosomes formed by repeated DNA replication and consisting of many chromatids side by side. [poly- + Latin taenia, band (from Greek tainiā, ribbon; see ten- in Indo-European roots).] pol′y·te′nic adj.pol′y·te′ny n. polyteny (ˈpɒlɪˌtiːnɪ) n (Biology) biology the condition of being polytene Polyteny Polyteny the presence in the nucleus of certain somatic cells of giant multifilamentous (polytene) chromosomes, which are hundreds of times larger than normal chromosomes. Polyteny leads to substantial increase in ploidy of the nuclei (up to 32.768N in Chironomus). Polyteny was first described in 1881 by the French cytologist E. Balbiani. Polytene chromosomes are observed in the cells of larvae of a number of Diptera (Chironomus, Drosophila), in Protozoa, and in some plant cells. Polyteny is the result of repeated replications of chromosomes without subsequent divsion of the cell or its nucleus. Giant chromosomes are characterized by specificity of location of the cross-bands, which permits compilation of chromosome maps and study of the functional activities of each band or group of bands. REFERENCES Lobashev, M. E. Genetika, 2nd ed. Leningrad, 1967. Swanson, C, T. Merz, and W. Young. Tsitogenetika. Moscow, 1969. (Translated from English.) M. M. ASLANIAN polyteny polyteny (pŏl″ĕ-tē′nē) [″ + tainia, band] Multiple lateral duplication of the chromosome. This produces a giant chromosome.
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