Drosophila Cytogenetics Early Milestones

Sutton's 1903 landmark paper, The Chromosomes in Heredity (5 see also ref. 6), in which he pointed out that the behavior of chromosomes in meiosis parallels the observed patterns of inheritance of Mendelian traits, is considered to mark the beginning of the field of cytogenetics (the actual term would be coined years later). Before then, cytology with its focus on animals specimens, and genetics, which consisted of breeding experiments involving mainly plants, had been separate areas of inquiry...

Oogenesis and Development of Nurse Cells

Oogenesis Drosophila

Each of the two paired ovaries of the adult Drosophila female consists of a cluster of parallel ovarioles, where egg chambers are lying in a single-file arrangement (see Fig. 1A,B). Each egg chamber contains a branching chain of 16 interconnected cystocytes formed by mitotic division of a germarial cystoblast (2). Fifteen of the cystocytes differentiate into endopolyploid nurse cells (NCs) (see Fig. 1C). The function of these germ-line-derived cells is to synthesize RNA and protein molecules,...

References

C., and Ripoll, P. (1978) The utilization during mitotic cell division of loci controlling meiotic recombination and disjunction in Drosophila melanogaster. Genetics 90, 531-578. 2. Baker, B. S. and Smith, D. A. (1979) The effects of mutagen-sensitive mutants of Drosophila melanogaster in nonmutagenized cells. Genetics 92, 833-847. 3. Szabad, J. and Bryant, P. J. (1982) The mode of action of discless mutations in Drosophila melanogaster. Dev. Biol. 93, 240-256. 4....

Use of Field Finders

Locating a small area of special interest on a glass slide e.g., a particular clean region of well-spread individual sperm nuclei , can be a tedious task of scanning a large area of the slide to reposition that same field on the microscope for cytophotometry. Ink marks or circles marked with a wax pencil are sometimes difficult to apply and often rub off. The job can be made much simpler by the use of a slide marked by a numbered and lettered grid see Fig. 15 . With this tool, it is possible to...

Mekkara Mandaravally Madhavan and Kornath Madhavan 1 Introduction

Abdomen Cuticle Clefts Drosophila

The epidermal cells, a derivative of ectoderm during embryogenesis of insects, contribute to the distinct cuticular pattern and form of the different stages that appear during their ontogeny. The type of cuticular products is the result of gene expression of the individual epidermal cells that lie immediately underneath these outgrowths 1 . In hemimetabolous insects, the larval epidermal cells LECs present at the time of hatching from the egg and their descendants are responsible for the...

The Feulgen Reaction for DNA

The Feulgen reaction for DNA was initially described by Feulgen and Rossenbeck in 1924 42 . They found that a mild acid hydrolysis of fixed tissue sections followed by treatment with Schiff's reagent 43 resulted in a dis- Hydrolysis Times in 5 N HCl for Invertebrate Tissues Prepared in Different Fixatives Hydrolysis Times in 5 N HCl for Invertebrate Tissues Prepared in Different Fixatives crete magenta coloring at the sites of DNA in their preparations. Mild acid hydrolysis splits off the...