Studies on Feulgen-DNA content in the polytene chromosomes of D. melanogaster T(1:4)wm258-21 heterozygotes showed that when the euchromatic region 3D1-E2 is located next to the heterochromatic breakpoint it contains less DNA than in the non-translocated homologue (Hartmann-Goldstein and Cowell, 1976). In contrast to the region adjacent to the breakpoint, region 3C1-10, which contains intercalary heterochromatin, shows more DNA in the translocated than in the non-translocated chromosome. Transposition may induce morphologically euchromatic regions containing putatively underreplicated sequences to undergo additional replication cycles. Region 2E1-3A4, distal to 3C1 and at some distance from the heterochromatic breakpoint is apparently unaffected. Extended replication and reduced DNA content in regions which have undergone chromosomal rearrangement could be accounted for by varying degrees of blockage of replication in individual strands of the polytene chromosome.
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http://dx.doi.org/10.1007/BF00327323 | DOI Listing |
Based on the morphology of the polytene chromosomes, 21 species of the genus Chironomus Meigen from Bulgaria have been identified. Original pictures of the polytene chromosomes are presented for each species. "Basic" sequences were determined for each arm of the polytene chromosomes which are used to determine the corresponding arms of the chromosomes, and the cytocomplex to which the species belongs.
View Article and Find Full Text PDFThe polytene chromosomes, larva, pupa, and male are described for the black fly Simulium chaouikaidi n. sp., a member of the Simulium venustum group from Morocco.
View Article and Find Full Text PDFPLoS One
October 2024
Department of Biological Sciences, University of South Alabama, Mobile, Alabama, United States of America.
Invasive species are a threat to ecosystems worldwide, but determining if a species is adventive or native is not always straightforward. The black flies that inhabit the Galapagos Islands, long known as Simulium ochraceum, are blood-feeding pests of humans and livestock. They first came to the attention of residents in 1989, suggesting a recent arrival.
View Article and Find Full Text PDFActa Trop
November 2024
International Center for Island Studies, Kagoshima University, Korimoto 1-21-24, Kagoshima, Japan.
Dokl Biol Sci
October 2024
Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia.
The transcription factor Z4 (putzig) is one of the key proteins that determine the chromatin structure in Drosophila. Z4 is found at the boundaries of bands on polytene chromosomes, and the bands are currently thought to correlate with chromatin domains. Z4 is a component of a protein complex that additionally includes Chromator and BEAF-32, and a conserved domain is necessary to occur at the N end of Z4 to ensure its interaction with the two proteins.
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