length from the proximal end. In salivary gland cells this chromosome consists of two euchromatic elements: a long distal one, and a short, proximal piece approximately l/20th as long. Both of these elements are connected with the nucleolus. It has also been proven that the nucleolus of the polytene X is located at a site corresponding to the secondary constriction of the metaphase chromosome, ...

Abstract Background Nine species of Chironomus evolved throughout the world were measured for their divergence with regard to DNA sequences concerning 18S rRNA since it is conserved a specific species. With advancement field molecular evolution, cytogenetics requires further correlation between architecture and morphological features compare amongst others decipher role in speciation. Therefore...

This vignette provides a tutorial that demonstrates the use of LDna on a RAD sequence landscape genomics data set from a Southeast Asian mosquito malaria vector, Anopheles baimaii. This species has a widespread distribution extending from Northeast India, through Myanmar and into Thailand. Prior polytene chromosome mapping studies suggests that one polymorphic inversion is found on each of the ...

We have used endonuclease treatment in situ, followed by Giemsa or ethidium bromide staining, for mapping repetitive sequences on the chromosomes of the flesh fly Sarcophaga bullata and thus for studying extrachromosomal DNA granules in this species. All three restriction enzymes employed (HaeIII, A1uI and HindIII) show the same cytological effects, except for a single interstitial band. In bot...

The locations of the larval serum protein one (LSP-1) alpha, beta and gamma genes were determined in Drosophila melanogaster and in 14 other species of Drosophila by in situ hybridization to polytene chromosomes. The LSP-1 alpha gene mapped to bands 11B on the X chromosome, the LSP-1 beta gene mapped to bands 21D-E on chromosome 2L, and the LSP-1 gamma gene mapped to band 61A in all the melanog...

The Drosophila melanogaster genome contains a single region (at 83DE on the polytene chromosome map) for which both heterozygous deficiency and heterozygous duplication are inviable. Seven EMS-induced mutations have been recovered that are viable in combination with a duplication of this region. Two classes of mutations are reported: (1) Mutations that allow survival of flies with either a dupl...

The region between 86F1,2 and 87B15 on chromosome 3 of Drosophila melanogaster, which contains about 27 polytene chromosome bands including the 87A7 heat-shock locus, has been screened for EMS-induced visible and lethal mutations. We have recovered 268 lethal mutations that fall into 25 complementation groups. Cytogenetic localization of the complementation groups by deficiency mapping is consi...

In human diploid cells, 23 pairs of chromosomes become recognizable as a discrete set of rod-shaped entities during the mitotic stage of the cell cycle. Upon exit from mitosis, they decondense and are packed together into the nucleus, in which individual chromosomes are no longer discernible. Nonetheless, evidence accumulated during past decades suggests that the decondensed chromosomes are not...

Peri-centromeric regions of Drosophila melanogaster chromosomes appear heterochromatic in mitotic cells and become greatly underrepresented in giant polytene chromosomes, where they aggregate into a central mass called the chromocenter. We used P elements inserted at sites dispersed throughout much of the mitotic heterochromatin to analyze the fate of 31 individual sites during polytenization. ...

Spatial organization of chromosome territories is important for maintenance of genomic stability and regulation of gene expression. Recent studies have shown tissue-specific features of chromosome attachments to the nuclear envelope in various organisms including malaria mosquitoes. However, other spatial characteristics of nucleus organization, like volume and shape of chromosome territories, ...