遗传学实验技术

Drosophila have two basic forms of chromosomes—mitotic and polytene—that have vastly different morphologies and cellular roles. Polytene chromosomes are found in interphase nuclei of differentiated cells, being especially prominent in certain tissues of the larva and adult ov ...

Immunostaining of mitotic chromosomes of larval neuroblasts by antibodies directed against specific proteins is a powerful tool for analyzing their distribution in both euchromatin and heterochromatin. This approach is particularly important for the structural analysis ...

The central nervous system (CNS) of the third instar larva is the most convenient tissue in which to examine both mitotic chromosomes and the diploid interphase nucleus. It contains a mixture of cell types at various degrees of differentiation. Here, methods for examining the diploid nuclei of t ...

The generation of dicentric chromosomes by site-specific recombination is a technique that has been used to study a number of different chromosomal phenomena, including: (1) the segregation of acentric chromosome fragments (1,2), (2) the behavior and resolution of chromosome bridges ...

The cytology of mitotic chromosomes has proved to be essential for research into different aspects of Drosophila biology. Cytological approaches are routinely used to study mutations that affect chromosome behavior or structure. Moreover, cytological methods are essential for ...

Most studies of the structure and function of Dipteran salivary gland poly-tene chromosomes are based on the phenomenon of the relative constancy of the banding pattern characteristic of each species. This made possible the building of cytological maps of polytene chromosomes widely u ...

Polytene chromosomes result from subsequent cycles of DNA replication that are not followed by nuclear division. In Drosophila, this occurs in the majority of larval tissues and is most prominent in salivary glands, where up to eleven rounds of replication events may occur. Because the repli ...

Even with the advent of sequenced genomes, the ability to locate aberration breakpoints onto the salivary chromosome map remains one of the singular strengths of Drosophila as a research organism. Salivary chromosome analysis is not difficult, yet many people are reluctant to attempt to do ...

Acetic orcein staining of polytene chromosomes was introduced in 1941 (1) shortly after the initial studies on aceto-carmine-stained chromosomes by Bridges (2) and has remained a standard method of preparation. Orcein dye can be purchased in both its natural form as extracted from two spec ...

Whole-mount fluorescence in situ hybridization (FISH) to chromosomes of Drosophila embryos is used to pinpoint the position of a chromosomal segment of interest, specified by the DNA probe(s), within a “preserved” three-dimensional nuclear structure. This technique has been used to (1) ...

Double-stranded RNA (dsRNA)-mediated interference, or RNAi, has emerged as an effective technique to phenocopy the loss of function of a given gene product. With this tool researchers can study the functions of individual molecules in living cells and elucidate the mechanisms that regul ...

One of the major foci in cell biology is to understand the process of nuclear division. In each cell cycle, the chromosomes must be faithfully replicated and the complex nuclear structure has to be duplicated and reorganized (1–4). Our understanding of the cell cycle and mitosis has increased dram ...

The Drosophila ovary has proven to be an excellent model system for addressing many key questions in biology. Among these are questions relating to the cell cycle control of DNA replication and chromosome structure during development. Early studies of ovarian chromosome dynamics emplo ...

The genome size of an organism, commonly known as its C value, is defined as the content of DNA (measured by weight or numbers of basepairs) in a single copy of the sequence of DNA found within the cells of an organism (i.e., the amount of DNA in a haploid chromosome set, where 1n=1C) (1). A single sperm of Drosophila melan ...

Polytene chromosomes from the salivary gland cells of Drosophila melanogaster larvae have been the most useful model for studying the functional morphology of interphase eukaryotic chromosomes since their discovery almost 70 yr ago (1). The question remains as to whether the polytene ...

Identification of the transcribed regions in the newly sequenced genomes is one of the major challenges of postgenomic biology. Among different alternatives for empirical transcriptome mapping, whole-genome tiling array experiment emerged as the most comprehensive and unbi ...

A hallmark genomic feature of human brain tumors is the presence of multiple complex structural and numerical chromosomal aberrations that result in altered gene dosages. These genetic alterations lead to widespread, genome-wide gene expression changes. Both gene expression as we ...

We present a detailed method to analyze DNA copy number data generated on cDNA microarrays. A web interface is made available for those steps in the workflow that are not typically used in gene expression analysis so that these steps can be carried out online. The end result of the analysis is a list of p-valu ...

Methods are described to take a list of genes generated from a microarray experiment and interpret these results using various tools and ontologies. A workflow is described that details how to convert gene identifiers with SOURCE and MatchMiner and then use these converted gene lists to sear ...

Astrocytoma is graded as pilocytic (WHO grade I), diffuse (WHO grade II), anaplastic (WHO grade III), and glioblastoma multiforme (WHO grade IV). The progression from low- to high-grade astrocytoma is associated with distinct molecular changes that vary with patient age, yet the prognosis of ...