Unit 1: Intro to Cytogenetics Flashcards
Branch of genetics that studies the structure of DNA within the cell nucleus
Cytogenetics
Studies the number and morphology of chromosomes.
Cytogenetics
Chromosome Banding Techniques
Classical Cytogenetics
Observed the section of cork by a primitive type of microscope and found that it was made up of small hollow units like honey comb. He termed the structural unit as cell.
1665, Robert Hooke (1635 - 1703)
Hybridization Fluorescently Labeled Probes
Molecular Cytogenetics
Published microscopic anatomy of plants and advanced a theory that the stamen corresponds to male, while pistil corresponds to female reproductive organ.
1672, Nehemiah Grew (1628 - 1711)
Published the information on his work of plant hybridization. He made hybrids between different varieties of tobacco and between some plant genera. By using reciprocal crosses, he showed the equal contribution of male and female parents to their offspring.
1761 - 1766, Joseph Gottlieb Kolreuter (1733- 1806)
Improved the microscope by the technique of grinding the lens. He reported the studies on free cells such as protozoa and bacteria and thus opened the door to a new world of microorganisms. He also studied blood cells.
1674, Anthony van Leeuwenhoek (1632 - 1723)
Showed the presence of sex in plants. He demonstrated that in maize, seeds are not produced unless pollen is applied to the pistil. He concluded that pollen is the male element, while pistil is the female element.
1694, Rudolf Jacob Camerarius (1665 - 1721)
Proposed a theory of evolution known as theory of inheritance
1809, Jean Baptiste Lamarck (1744-1829)
Theory of Inheritance of acquired characters:
-
Variation in an individual is brought about by:
(a) conscious effort
(b) reaction to environment
(c) use and disuse of the organ - Heredity carries forward the changes that are acquired during the life time of the individual.
Studied plant cells and discovered nucleus in Tradescantia. He described it as a central feature of living cells.
1828, Robert Brown (1773 - 1858)
Described cell division and showed that cells arise through partition walls formed between preexisting cells.
1835, Hugo von Mohl (1805-1872)
Put forth the cell theory
1838 - 1839, Matthias Jacob Schleiden (1804-1881) and Theodor Schwann (1810-1882)
Cell Theory Results
- Cell is the smallest structural element
- In a multicellular organism, every cell has a specific function to perform
- A cell can only be produced from another cell by cell division
1st discovered chromosomes in pollen
1842, Karl Nageli
Introduced aniline staining to observe chromosomes during cell division
1870, Walther Flemming
Derived an estimate of 48 chromosomes using images of nuclei reconstructed from thin sections of human testicular tissue embedded in paraffin and stained with iron hematoxylin
1923, Theophilus Painter
Greek word of Chromosomes
“Chroma” - Colored
“Soma” - Body
Coined the term “chromosome” after staining techniques had been developed
1888, Waldeyer
To describe the deeply staining properties of these structures during cytological analysis
Colored Body
What was discovered in 1950
Cytogenetic technique improvements (use of colchicines to arrest cells in metaphase)
Showed that human cells have 23 pairs of chromosomes
1956, Tijo & Levan
What was discovered in 1960?
Peripheral leukocyte culture method of Moorehead et al. was adopted by many cytogeneticists
1 nuclear genome = _____ genes
25,000
1 mitochondria genome = __ genes
37
Peripheral Leukocyte Culture Method Procedures
- Extract 5 mL venous blood
- Add phytohemagglutinin & culture medium
- Culture at 37C for 3 days
- Add colchicine & hypotonic saline
- Cells fixed by alcohol
- Spread cells onto slide by dropping
- Digest with trypsin and stain with Giemsa
- Analyze “metaphase spread”
Why is Hypotonic Saline used in Peripheral Leukocyte Culture Method?
To make the cell swell (more visible)
Technique developed by Joseph Gall and Mary Lou Pardue in 1960s
In situ hybridization
Basic unit of inheritance
Gene
Determines the gene
DNA
Helps detect whether the gene is present and where it is located
Fluoresence In Situ Hybridization (FISH)
Father of Genetics
Gregor Mendel
In 1865, Mendel discovered ______
Paired Factors
- Aare inherited
- Segregate during gamete formation
- Independently sort
Paired Factors
In 1902, Sutton & Boveri discovered the _________
Chromosome Theory of Inheritance
Chromosomes occur in pairs & are inherited from parents (the paternal & maternal chromosome)
Chromosomal Theory of Inheritance
Chromosomes segregate in gamete formation (haploid)
Chromosomal Theory of Inheritance (Not a paired factor but rather dependent on the chromosome)
Chromosome pairs segregate independently
Chromosomal Theory of Inheritance
First genetic linkage map
Polytene Chromosomes Isolation from Fruit Fly and First Plant Cytogenetics
Genetic Linkage Map of Polytene Chromosomes Isolation from Fruit Fly and First Plant Cytogenetics
- Polytene chromosomes were first discovered in insects (Balbiani 1881)
- Morgan, Sturtevant, Bridges and Muller made the 1st genetic linkage maps from fruit fly
- 1920, Cyril Darlington pioneered plant cytogenetics
Scientists behind Polytene Chromosomes Isolation from Fruit Fly and First Plant Cytogenetics
- Thomas Hunt Morgan
- Calvin Bridges
- Alfred Sturtevant
- Herman Muller
Findings of Polytene Chromosomes Isolation from Fruit Fly and First Plant Cytogenetics
It proved that it is directly linked to your chromosome, which is the gene
In 1944, (DNA/Protein) and not (DNA/Protein) in chromosome is the heredity material (Genetic Transformation Expt.)
DNA ; Protein
He discovered the amount of nitrogen base in chromosome
Chargaff (Chargaff’s Rule) (1950)
Term used for chromosomes crossing arms then it interchanged
Biodiversity / Recombinant
Discovered the double helix in 1953
Watson & Crick
Discovered the genetic code in protein synthesis in 1961
Crick, Brenner et al.
Described the conversion of a non-pathogenic pneumococcal bacteria to a virulent strain.
Frederick Griffith
Why did the mouse die when injected with rough strain & heat-killed smooth strain?
Bacterial Transformation: The smooth strain gave its genetic material to rough strain because the heat didn’t kill the DNA
How did Chargaff discovered the amount of nitrogen base in a chromosome?
The DNA bases were almost equal in numbers.
A (29.3) = T (30)
C (20) = G (20.7)
The key understanding for the double helix model
Rosalind Franklin’s Xray Diffraction DNA
Studies the RNA
Gene Expression
Central Dogma
DNA → RNA → Protein
DNA microarrays are used instead of traditional metaphase chromosome preparation
Array CGH
First reported the CGH analysis, who utilized CGH in the analysis of solid tumors
Kallioniemi and colleagues
Array CGH was pioneered by ______ in 1997 using tumor cells and _______ in 1998 by the use of breast cancer cells
Solinas-Tolodo et al. & Pinkel et al.
Term used when there is a missing chromosome
Copy Loss
A technique that permits the detection of chromosomal copy number changes without the need for cell culturing. It provides a global overview of chromosomal gains and losses throughout the whole genome of a tumor.
Comparative Genomic Hybridization
Term used when there is an increased in chromosome
Copy Gain
Extra chromosome in the 21st pair
Trisomy 21 / Down Syndrome
Absence of Y chromosome
45, X / Turner Syndrome
Extra X chromosomes
47, XXY / Klinefelter Syndrome
With a combination of these conventional and molecular techniques, _______ has become an indispensable tool for the diagnosis of various genetic disorders, paving the way for possible treatment and management
Cytogenetics
Additional copy of chromosome 13 in some or all of the body’s cells
Trisomy 13 / Patau Syndrome
Caused by an extra copy of
chromosome 18
Trisomy 18 / Edward’s Syndrome
Causes chronic myeloid leukemia
Philadelphia Chromosome
T/F: cells cultured from amniotic fluid could be used to determine the chromosome content of the fetus
true
Prenatal diagnosis of common aneuploidies, non-invasive detection of chroma disorders using maternal blood, and studies of mosaicism are included under which importance of cytogenetics?
Pre-natal studies
importance of cytogenetics
- Pre-natal studies
- human cancer studies
- detection of subtelomeric aberrations
- microdeletion syndrome detection
which aneuploidies chromosomes cause 95% of chromosomal aberrations causing live-born birth defects ?
chromosome 13, 18, 21, X and Y
Modern detection technique of aneuplodies chromosomes is through ?
interphase FISH prenatal diagnosis w/ uncultured amniocutes
_______ is a useful and non-invasive method for prenatal diagnosis of chromosomal disorders
Maternal blood cytogenetic analysis of fetal cells by FISH
Cell source for non invasive prenatal genetic diagnosis
Fetal nucleated RBC
Detection of Specific Translocations and Gene Rearrangements, Analysis of Gains and Losses of Chromosomes or Chromosomal Regions in Tumors, and Testing Deletion of Tumor Suppressor Genes and Amplification of Oncogenes are under what importance of cytogenetics?
Human cancer studies
Why is the identification of specific chromosomal translocations and gene rearrangements important
- determining a therapy plan
- monitoring treatment
- predicting prognosis
___________ can detect chromosomal translocations in hematologic neoplasms, malignant lymphomas, and solid tumors
Molecular Cytogenetics
For patients with chronic myeloid leukemia, it has been shown that ______ is highly sensitive in detecting the BCR/ABL fusion
interphase FISH
What is used to detect specific genes in many cases of acute leukemia?
molecular cytogenetics
T/F: Almost all types of clinical specimens can be used for CGH studies of tumors
True
Through the ________ approach, chromosomal aneuploidies can be detected without cell culturing in any given tissue or cell source
Molecular Cytogenetics interphase FISH
T/F: Molecular cytogenetics FISH requires cell culturing to detect chromosomal aneuploidies
False, chromosomal aneuploidies can be detected without cell culturing in any given tissue or cell source
Gains or losses of individual chromosomes or chromosome regions is helpful for what?
- correlation to tumors and its different stages
- used for prognosis
T/F: Deletion of tumor supressor genes and amplification of oncogenes can be detected by FISH or CGH studies
True
analysis of genomic alterations using mainly in situ hybridization based technology
Molecular cytogenetics
Molecular cytogenetics employ ________ to analyze genomic alterations
in situ hybridization