3-Cytogenetics Flashcards
What is the study of chromosomes and their abnormalities. Itincludes the study of normal and abnormal chromosomes, and investigation of the causes of chromosomal
abnormalities?
Cytogenetics
Who discovered chromosomes in pollen by observing the process of cell division during pollen formation
Carl Nägeli
Carl Nägeli discovered chromosomes in pollen by observing the process of cell division during pollen formation, where he noticed distinct structures within the nucleus that he called ?, which were later identified as chromosomes.
transitory cytoblasts
Who introduced aniline staining, which allowed chromosomes to be visualized during cell division. This method marked nucleic acids, leading to the first illustrations of chromosomes.
Walther Flemming
The term “chromosome, “ meaning ?, reflects their ability to absorb dyes like aniline.
“color body”
Who estimated 48 chromosomes using outdated techniques?
Theophilus Painter
Theophilus Painter estimated 48 chromosomes using outdated techniques. This was corrected in 1956 by ?, who demonstrated that human cells have 23 pairs of chromosomes
Tjio and Levan
Detection of Genetic Mutations Examines the number and structure of chromosomes to detectmabnormalities
Chromosome Analysis
What is a standard method used to visualize chromosomal arrangements.
Karyotyping
Identifies the location of specific genes on chromosomes, aiding in understanding genetic inheritance and disease mechanisms.
Gene Mapping
Identifies mutations at the chromosomal level that cause diseases.
Detection of Genetic Mutations
Used to track chromosomal changes during disease progression, especially in cancer, and to evaluate treatment responses
Monitoring Disease Progression
Cytogenetics studies chromosomal variations among species, contributing to,evolutionary biology and,understanding,genetic diversity
Research on Evolution and Biodiversity
The process of analyzing cells in a sample of tissue, blood, bone marrow, or amniotic fluid to look for changes in chromosomes, including broken, missing, rearranged, or extra chromosomes. Changes in certain chromosomes may be a sign of a genetic disease or condition or some types of cancer.
Cytogenetic analysis
What analysis may be used to help diagnose disease, plan treatment, or find out how well treatment is working
Cytogenetic analysis
Kinds of Cytogenetic Examination:
Basic Chromosomal Analysis
Molecular Cytogenetic Analysis
Definition:
This is the traditional method of cytogenetic examination that involves analyzing the structure, number, and arrangement of chromosomes under a microscope.
Basic Chromosomal Analysis
This technique involves staining chromosomes to produce specific banding patterns, which help in identifying individual chromosomes and detecting structural abnormalities.
Chromosome Banding
- Uses quinacrine, a fluorescent dye, to stain chromosomes.
- Produces bright and dark bands under a fluorescence microscope.
- G-C rich regions fluoresce more brightly than A-T rich regions.
- Used for identifying specific chromosome abnormalities.
Quinacrine Banding (Q-banding)
- Uses Giemsa stain after enzyme treatment (typically trypsin).
- Produces a pattern of dark and light bands similar to Q-banding.
- Dark bands are A-T rich and gene-poor, while light bands are G-C rich and gene-rich.
- The most commonly used banding technique in karyotyping
Giemsa Banding (G-banding)
Opposite pattern of G-banding. Chromosomes are heat-treated before staining. G-C rich regions stain dark, and A-T rich regions stain light. Useful for highlighting telomeric and gene-rich regions.
Reverse Banding (R-banding)
- Stains constitutive heterochromatin, mainly in centromeric regions.
- Uses alkali or acid treatment before Giemsa staining.
- Helps identify centromeric heterochromatin and certain chromosomal abnormalities.
C-banding
- Stains nucleolar organizer regions (NORs), which contain ribosomal RNA genes.
- Uses silver staining to highlight NORs.
- Identifies active ribosomal RNA gene sites, typically found on acrocentric chromosomes
Nucleolar Organization Stains (NOR-staining)
What is the process of organizing and analyzing an individual’s complete set of chromosomes (karyotype) to detect abnormalities in number or structure.
Karyotyping
This modern technique combines molecular biology with cytogenetics to detect specific DNA sequences or structural changes with high resolution.
Molecular Cytegenetic Analysis
What uses fluorescent probes to identify specific DNA sequences on chromosomes. This technique has higher resolution than karyotyping and can be used on interphase cells
Fluorescence In Situ Hybridization (FISH)
What is a molecular cytogenetic technique that detects chromosomal copy number variants, such as duplications or deletions, without needing cell culturing. It compares a test sample with a control sample, both labeled with different fluorescent markers. It can scan the whole genome for chromosomal imbalances and is particularly useful when the diagnosis is unknown. However, it has a resolution limit of 5-10 megabases and is not suitable for detecting smaller genetic alterations.
Comparative Genomic Hybridization (CGH)
This advanced molecular cytogenetic technique uses multiple fluorescently labeled probes, each specific to an individual chromosome, to produce a distinct color for each chromosome.
Spectral Karyotyping (SKY) Technique
