MT6315 L1 INTRO TO CYTOGEN Flashcards
What is cytogenetics?
branch of genetics that studies the structure of DNA within the cell nucleus
The cytogenetic studies the number and morphology of chromosomes. Using chromosome banding techniques (classical cytogenetics) or hybridization fluorescently labeled probes (molecular cytogenetics).
What is classical and molecular cytogenetics?
Classical - banding techniques
Molecular - Fluorescently labeled probes
What are the stages of the development of cytogenetics?
Cell Discovery
Discovery of chromosome structure and components
Human cytogenetics emergence
Who discovered plant hybridization?
Joseph Gottlieb Kolreuter
How did Kolreuter prove plant hybridization? What did he discover?
By making hybrids of plants from tobacco and other plant genera
There are equal contributions of male and females in the offspring
When did Kolreuter make his dosciveres?
1761-1766
What did Anton van Leuwenhoek discover?
First used the word cells by observing a piece of cork under a primitive microscope
Small hollow units like honeycomb – cells
What did Nehemiah Grew discover?
stamen is to males
pistil is to females
Published the microscopic anatomy of plants
Who showed that there is presence of sex in plants?
Rudolph Jacob Camerarius
How did Camerarius come to his conclusion?
Cross breeding maize plants and discovered that seed are not produced until pollen reaches the pistil
What did Hugo van Mohl discover?
cell division
cells arise through partition of existing cells
Who formulated the cell theory?
Matthias Jacob Schieiden and Theodor Schwann
What is the cell theory?
The cell is the smallest structural element of a multicellular organism and as a unit, it is itself an elementary organism.
In a multicellular organism, every cell has a specific function to perform, and represents a working unit.
A cell can only be produced from another cell by cell division.
Who discovered nucleus in Tradescantia?
Robert Brown
What did Jean Baptiste Lamarck discover?
Theory of inheritance of acquired characters
What is the theory of inheritance of acquired characters?
1.) Variation is brought about by conscious effort, reaction to the environment and use or disuse of organ
2.) Heredity carries forward the changes acquired
What did Anthony van Leeuwenhoek study?
Bacteria and protozoa
Who discovered chromosomes in pollen?
Karl Nageli
What did Walther Flemming introduce?
Aniline to better visualize chromosomes during cell division
Who coined the term chromosome after staining techniques were developed?
Waldeyer
What did Theophilus Painter discover?
~48 chromosomes using images of nuclei reconstructed from human testicular tissue embedded in paraffin and stained w/ iron hematoxylin
X/Y chromosomal pair mechanism
Aniline is a poisonous substance derived from ______.
coal tar
What is the etiology of chromosomes?
Chromo - colored
somes - bodies
Who further developed the discovery of Theophilus Painter?
Tijo and Levan
What did Tijo and Levan discover?
23 pairs of chromosomes through arresting the chromosomes in metaphase stage using colchicine and squashed tissue was used
C-banding stains highly repetitive _______-rich regions, most often the centromeres where the chromosomal arms meet, revealing these regions. G-banding, similarly, uses ______ stain to mark heterochromatic regions, which are tightly wound and (more/less) transcriptionally active. Q-banding uses ______ for similar results, but also fluoresces in proportion to the AT enrichment of the part of the chromosome to which it binds, providing more information.
cytosine
Giesma; less
quinacrine
What type of banding enabled the critical innovation of karyotyping?
G- and q-banding
What did Moorehead et al. discover?
peripheral leukocyte culture method
What are the steps of peripheral leukocyte culture method?
1.) 5mL venous blood
2.) Add phytohemagglutinin and culture medium
3.) Culture for 3 days @ 37C
4.) Add colchicine and hypotonic saline
5.) Fix cells
6.) Spread on slide by dropping
7.) Digest w trypsin and stain w Giemsa
8.) Analyze metaphase spread
9.) Karyotype
Who discovered FISH?
Joseph Gall and Mary Lou Pardue
What are paired factors according to Mendel?
inherited
segregate during gamete formation
independently sort
What are paired factors according to the Chromosomal Theory of Inheritance by Sutton and Boveri?
Chromosomes occur in pairs & are inherited from parents (the paternal & maternal chromosome)
Chromosomes segregate in gamete formation (haploid)
Chromosome pairs segregate independently
How was the first genetic linkage map created?
From polytene chromosomes in a fruit fly and the first plant cytogenetics
Polytene chromosomes were first discovered in insects
Morgan, Sturtevant, Bridges and Muller made the 1st genetic linkage maps from fruit flies
Cyril Darlington pioneered plant cytogenetics
Who is Frederick Griffith?
Experimented strains of viruses on mice that led to the discovery of horizontal gene transfer
Discovered that DNA can be transferred since it is the carrier of genetic information
What in the chromosome holds the genetic information?
DNA
What is Chargaff’s rule?
Amount of nitrogenous bases in the chromosomes
A = T
C = G
A+T+C+G = 100
A + T cannot equal C + G
When was the first report of CGH analysis?
1992 by Kallionemi and Colleagues who utilized CGH in the analysis of solid tumors
What is CGH and aCGH?
Comparative Genomic Hybridization
Array Comparative Genomic Hybridization
What did Pinkel, et al. and Solinas-Tolodo discover?
Used microarrays instead of traditional metaphase chromosome preparation used in tumor cells (Solinas - Toledo)
Used in breast cancer cells (Pinkel)
What did the emergence of human cytogenetics lead to?
enabled detection of numerical chromosome aberrations
What is 45, X?
Turner Syndrome
baby assigned female at birth is born with one missing or partial X chromosome
What can FISH method reveal?
the number of chromosomes,
the presence or absence of particular sequences,
translocation events
What are microscope slides with thousands of tiny spots on which DNA or RNA probes are attached?
Microarrays
What is the genetic code for Klinefelter?
47, XXY
What illness is Philadelphia chromosome present in?
chronic myeloid leukemia
T or F: Turner syndrome can be observed in both males and females.
F, only females
T OR F: It was also reported that cells cultured from amniotic fluid could be used to determine the chromosome content of the fetus
T
What happens in Philadelphia Chromosome?
Translocation between chromosome 9 and 22
Associated w CML
Importance of Cytogenetics includes?
- Pre-natal studies
- HUMAN CANCER STUDIES
-DETECTION OF SUBTELOMERIC ABERRATIONS IN PATIENTS WITH UNEXPLAINED MENTAL RETARDATION
-MICRODELETION SYNDROMES DETECTION
What are common prenatal aneuploidies?
13, 18, 21, X and Y
How is detection done is prenatal diagnosis?
interphase FISH prenatal diagnosis with uncultured amniocytes.
What is a useful method of prenatal diagnosis for chromosomal disorders?
Maternal Blood Cytogenetic analysis of fetal cells by FISH
What is the result of post fertilization mitotic error?
Constitutional mosaicism
What do meiotic and somatic mosaicism determine?
origin of the extra chromosome in the trisomic line
What is meiotic mosaicism vs somatic mosaicism?
Meiotic - mitotic error in producing diploid cell
Somatic - trisomic line occurred in conception which was initially diploid
What are important for determining a therapy plan?
identification of specific chromosomal translocations and gene rearrangements
Molecular cytogenetics in cancer studies can detect translocations in?
neoplasms, malignant lymphomas, and solid tumors
For patients with chronic myeloid leukemia, it has been shown that interphase FISH is highly sensitive in detecting?
BCR/ABL fusion
In acute leukemia, the involvement of the ______ and _______ can be detected in Molecular cytogenetics.
MLL gene in an 11q23 rearrangement and the TEL/AML1 fusion in childhood acute lymphoblastic leukemia.
T or F: Through the Molecular Cytogenetics, interphase FISH approach, chromosomal aneuploidies can be detected with cell culturing
F; without
T or F: Almost all types of clinical specimens can be used for CGH studies of tumors
T
Gains or losses of individual chromosomes or chromosome regions is correlated with?
particular tumors, different stages of the tumor, and can be used in the prognosis of patients
In cancer studies, FISH or CGH studies can detect?
Deletion of tumor suppressor cells and amplification of oncogenes
