Related Experiment Video
Updated: Aug 4, 2026

07:34
FISH for Pre-implantation Genetic Diagnosis
Published on: February 23, 2011
Philadelphia chromosome-negative chronic myelogenous leukemia with trisomy D
Archives of Pathology & Laboratory Medicine
|July 1, 1980
Abstract:
Previous reports emphasize that trisomy 8 is the most common, single chromosomal abnormality in both Philadelphia (Ph1) chromosome-positive and Ph1-negative chronic myelogenous leukemia (CML). Karyotype analysis on a 78-year-old man with Ph1-negative CML showed trisomy D, confirmed on banding studies to be an extra No. 14 chromosome. Although the abnormality is likely to be related to the leukemic clone, the importance of this chromosomal deviation is not known.
Related Concept Videos
Meiosis I
Meiosis is a carefully orchestrated set of cell divisions, the goal of which—in humans—is to produce haploid sperm or eggs, each containing half the number of chromosomes present in somatic cells elsewhere in the body. Meiosis I is the first such division, and involves several key steps, among them: condensation of replicated chromosomes in diploid cells; the pairing of homologous chromosomes and their exchange of information; and finally, the separation of homologous chromosomes by a...
Karyotyping
Describing the number and physical features of chromosomes can reveal abnormalities that underlie genetic diseases. This description is facilitated by special staining techniques that produce a particular banding pattern on each chromosome. State-of-the-art techniques make this approach even more powerful, enabling the detection of individual genes that cause disease.A Simple Chromosome Staining Technique Provides Valuable Scientific InsightSome genetic diseases can be detected by looking at...
Nondisjunction
During meiosis, chromosomes occasionally separate improperly. This occurs due to failure of homologous chromosome separation during meiosis I or failed sister chromatid separation during meiosis II. In some species, notably plants, nondisjunction can result in an organism with an entire additional set of chromosomes, which is called polyploidy. In humans, nondisjunction can occur during male or female gametogenesis and the resulting gametes possess one too many or one too few chromosomes.
Polytene Chromosomes
Polytene chromosomes are giant interphase chromosomes with several DNA strands placed side by side. They were discovered in the year 1881 by Balbiani in salivary glands, intestine, muscles, malpighian tubules, and hypoderm of larvae Chironomus plumosus. Hence, these are also called "Salivary gland chromosomes." These are found in insects of the order Diptera and Collembola; in certain organs of mammals; and synergids, antipodes of flowering plants. Polytene chromosomes are also regularly...

