Chromosomal Structure and Chromosomal Mutations Flashcards
Diploid
Having two of each chromosome.
Haploid
Having one of each chromosome.
Phenotype
A trait resulting from transcription and translation of genes.
Euploid
A cell or cell population with a normal complement of chromosomes.
Balanced Polymorphism
A DNA sequence difference, the phenotypic effect of which is counteracted by a second trait or polymorphism.
Euploid
A cell or cell population with a normal complement of chromosomes.
Aneuploid
Cells with a genome mutation, having an abberant number of chromosomes per nucleus. Can be detected by indirect methods such as flow cytometry and karyotyping.
Centromere
A repetitive sequence of DNA, the site of attachment of the chromosome to the spindle apparatus.
Metacentric
The arms of the chromosome are of equal size.
Submetacentric
The chromosome has a large arm and a short arm.
Acrocentric
Centromeres are very near the end of the chromosome.
q
The long arm of the chromosome.
p
The short arm of the chromosome.
DAPI
4’6-diamidino-2-phenylindole, a fluorescent stain. Used to visualize chromosomes. A way to detect mycoplasmal contamination in cell cultures.
Translocations
The exchange of the genetic information between chromosomes, the breakage and fusion of separate chromosomes.
Reciprocal Translocations
Exchange of DNA between separate chromosomes with no gain or loss of genetic information.
Balanced Translocation
When there is no loss or gain of chromosomal material.
Deletion
A loss of chromosomal material.
Insertion
A gain or duplication of chromosomal material.
Inversions
Excision, flipping, and reconnecting chromosomal material within the same chromosome.
Pericentric Inversions
Excision, flipping, and reconnecting chromosomal material within the same chromosome. Include the centromere in the inverted area.
Paracentric Inversions
Excision, flipping, and reconnecting chromosomal material within the same chromosome. Involve inversions within one arm of the chromosome.
Isochromosome
A chromosome containing two copies of the same arm and loss of the other arm.
Ring Chromosome
A circular structure that results from deletion of genetic regions from ends of the chromosome and a joining of the ends of the chromosome to form a ring.
Derivative Chromosome
An abnormal chromosome consisting of translocated or otherwise rearranged parts from two or more unidentified chromosomes joined to a normal chromosome.
FISH
Fluorescence In Situ Hybridization. A method used to detect protein and RNA as well as DNA structures in place in the cell using probes.
In Situ
In place.
Interphase FISH
Used to study prenatal samples, tumors, and hematological malignancies. Does not require culturing of cells. Cytogenic probe analysis of mitotic nuclei.
Dual-fusion Probes
Dual-color probes. Mixture of two different colored probes. FISH probe designed to detect translocation and their reciprocal products.
Break-apart Probes
Decrease background signals as well as to identify translocation events where one chromosome can recombine with multiple potential partners. They bind to the chromosome and then separate when a translocation occurs.
Centrometric Probes
CEN probes. A probe that binds to centrosomes.
Designed to hybridize to highly repetitive alpha satellite sequences surrounding centromeres. They detect aneusomy of any chromosome.
Centrometric Probes
CEN probes. Designed to hybridize to highly repetitive alpha satellite sequences surrounding centromeres. They detect aneusomy of any chromosome.
Telomere
The end of the chromosome.
Telomeric Probes
Probes that bind to telomeres. Detect structural abnormalities that are not easily identified by karotyping.
Photobleaching
Fading or loss of probe signal emission due to photochemical destruction of the fluorophore molecules.
Metaphase FISH
Cytogenic analysis of metaphase chromosomes, small regions not visible by regular chromosome banding.
Whole Chromosome Paints
Probes that cover the entire chromosome. Valuable for detecting small or complex rearrangements.
Spectral Karotyping
Cytogenic probe analysis that can distinguish all 23 chromosomes during metaphase by chromosome-specific colors using special imaging software.
CGH
Comparative Genome Hybridization. Can detect intrachromosomal amplifications or deletions. DNA from test and reference samples is labeled and used as a probe on a normal metaphase chromosome spread. Can identify the deletions or amplifications throughout the genome.
Aberrant
Diverging from the normal.
Chromosome
DNA molecules condensed.
Cytogenic
Genetic Material.
Phenotype
The set of observable characteristics in an individual resulting from the genotype interacting with its environment.
Meiosis
Replication and separation of DNA by reductional and equational divisions in diploid organisms, resulting in four haploid products.
Flow Cytometry
A technique used to detect and measure physical and chemical characteristics of a population of cells or particles. In this process, a sample containing cells or particles is suspended in a fluid and injected into the flow cytometer instrument. Used to test the cells from bone marrow, lymph nodes, and blood samples.
Spindle Apparatus
Mitotic spindle. Refers to the cytoskeletal structure of eukaryotic cells that forms during cell division to separate sister chromatids between daughter cells.
Mycoplasmal
A genus of bacteria that lack a cell wall around their cell membranes. This characteristic makes them naturally resistant to antibiotics that target cell wall synthesis.
aneusomy
The condition in which an organism is made up of cells that contain different numbers of chromosomes.
Nucleosome
160-180 bp DNA wrapped around 8 histones.
Apoptosis
Programmed cell death.
Q Banding
When chromosomes are stained, fluorescence pattern visualized after staining with quinacrine and quinacrine mustard.
Hematology
The study of the physiology of the blood.
Equational Division
A method of reproduction; a rarely used synonym for mitosis. As a result of equational division the initial number of chromosomes in the cell is preserved.
Reductional Division
The first cell division in meiosis, the process by which germ cells are formed. The chromosome number is reduced from diploid (46 chromosomes) to haploid (23 chromosomes). Also known as first meiotic division and first meiosis.
High Resolution Banding
Increase the number of visualized bands can be increased from 300 to 500 per chromosome by staining chromosomes before they reach maximal metaphase condensation.
Histones
The most abundant proteins in a cell. Highly basic proteins abundant in lysine and arginine residues that are found in cell nuclei. They act as spools around which DNA winds to create structural units called nucleosomes. Help prevent DNA from becoming tangled and protect it from DNA damage. In addition, histones play important roles in gene regulation and DNA replication. Without histones, unwound DNA in chromosomes would be very long.
Nucleosome
160-180 bp DNA wrapped around 8 histones. The basic structural unit of DNA packaging. The structure of consists of a segment of DNA wound around eight histone proteins and resembles thread wrapped around a spool. The nucleosome is the fundamental subunit of chromatin. Each nucleosome is composed of a little less than two turns of DNA wrapped around a set of eight proteins called histones, which are known as a histone octamer. Each histone octamer is composed of two copies each of the histone proteins H2A, H2B, H3, and H4.
Kinetochore
A disc-shaped protein structure associated with duplicated chromatids where the spindle fibers attach during cell division to pull sister chromatids apart. The kinetochore assembles on the centromere and links the chromosome to microtubule polymers from the mitotic spindle during mitosis and meiosis.
Alpha Satellite
Single stranded satellite DNA that are dependent on a virus for transmission. The genome is a single circular single strand DNA molecule.
Mitogen
A peptide or small protein that induces a cell to begin cell division: mitosis. The mechanism of action of a mitogen is that it triggers signal transduction pathways involving mitogen-activated protein kinase, leading to mitosis.
Metaphase Chromosome
Chromosomes in the second phase of mitosis, chromosomes are at their second most condensed and coiled stage.
