遗传学实验技术

The principle of producing mitotic chromosome preparations for analysis by banding techniques and by in situ hybridization is to synchronize the cells by blocking them at cell cycle stages preceding mitosis (Gl or S phase), then releasing the block, and allowing the maximum number of cells to r ...

Telomeres are the specialized structures that define chromosome ends and have been the subject of several recent reviews (1–5). Telomeres allow a linear replication unit to be maintained as a linear molecule and overcome the end replication problem. The telomere must also distinguish a bona ...

Hybrid cells are proving to be an important resource in the genetic analysis of chromosome regions. These hybrids may take the form of fusions between somatic cells from different genera, followed by selection for specific chromosome markers (somatic cell hybrids—see Chapter 17), the int ...

In situ hybridization provides a means of analyzing chromosomal aberrations in a very direct way. Nucleic acid probes are hybridized to chromosomal preparations, and the site of specific hybridization is detectable by various procedures. Although in the 1970s and 1980s isotopic dete ...

Since the first reports of the Philadephia chromosome in chronic myelogenous leukemia (CML), nonrandomly occurring chromosome abnormalities have been described in a number of leukemias and lymphomas (1,2). The identification of the DNA sequences that span the translocation brea ...

Microdissection and microcloning involve the physical removal of chromosome fragments and the cloning of the collected DNA using specialized microprocedures. Microdissection represents the most direct method for recovery of cloned DNA from an individual chromosome region ...

Use of scanning electron microscopy (SEM) to study chromosomes permits their observation at higher resolution than is possible by light microscopy and, at the same time, provides aesthetically pleasing images. Chromosome preparations made for SEM in the three different ways describ ...

The large cloning capacity of Yeast Artificial Chromosomes (YACs) (1) makes them a powerful reagent for long-range mapping and cloning toward contiguous chromosomal maps. Full value is to be attained through an integrated, global strategy (Fig. 1), including both

The Yeast Artificial Chromosome (YAC) (1) technology allows the cloning of large fragments of DNA (several hundreds of kilobase pairs, kbp) into the budding yeast Saccharomyces cerevisiae, and therefore bridges a gap between conventional cloning in bacteria (λ and cosmid cloning) and so ...

Linkage studies in humans are strictly limited by such factors as family structure, the availability of material for study, and informative markers for linkage analysis. Parasexual approaches therefore have a particularly important role to play in human genetics (1). A panoply of somat ...

In situ hybridization is used to map the position of DNA or RNA sequences relative to cytologically-identifiable landmarks. Although major progress has been made in sequence mapping at the light microscope (LM) level, there are inherent limits to resolution, notably when sequences are cl ...

The technique of in situ hybridization has come of age, it being more than 21 years since the first descriptions of the procedure were published (1). In that time, the capabihties of the method have expanded enormously. In the early years, the sensitivity (minimum size of target capable of being detect ...

Unequivocal physical ordering of genes and genetic markers along chromosomes has been an essential component of gene mapping for much longer than the span of the current genome mapping effort. Human geneticists contemplate mapping a gene as soon as its presence can be identified either dir ...

During the prophase of the first meiotic division, homologous chromosomes align, pair, recombine, and segregate. These processes are accompanied by the appearance of meiosis-specific structures. Chromosome alignment is accompanied by the formation of axial elements along each ...

The study of chromosomes at meiosis in humans commenced in 1956, when Ford and Hamerton (1) published the first pictures of metaphase I complements of human spermatocytes prepared by “squashing,”the only technique available to the meiotic cytogeneticist at that time. A major advance in tec ...

Immunofluorescence has proven to be a powerful technique for the in situ localization of antigens at a cytological level. Whether utilized to determine the cellular distribution of known antigens using defined antibodies, to aid in the characterization of novel antigens recognized, ...

Electrophoretic karyotyping is a term first introduced by Carle and Olson in 1985 (1) to describe the use of the new technique of pulsed field gel electrophoresis (PFGE) to visualize whole chromosomes from unicellular organisms. Conventional agarose gel electrophoresis has a useful up ...

Bivariate flow cytometry is now able to resolve the majority of chromosomes of the human karyotype (1,2 and Chapter 12). When this is coupled to a sorting facility, specific chromosomes can be separated and purified in small, but useful quantities. These chromosomes have been used for the product ...

The bivariate analysis of human chromosomes in flow using the fluorochromes Hoechst 33258 (with specificity for AT-rich DNA) and Chromomycin A3 (with specificity for GC-rich DNA) was first described by Gray et al. in 1979 (1). Chromosomes stained with these two dyes can be resolved on the flow cyto ...

This chapter differs from the majority in this book in that its subject matter is the application of computer image interpretation techniques to the analysis of metaphase chromosome spreads. Were we to follow the prescription of the remainder of the book, we might simply publish the code of a compu ...