Cytogenetics focuses on the microscopic examination of genetic components of the cell, including chromosomes, genes, and gene products. Older cytogenetic techniques involve placing cells in paraffin wax, slicing thin sections, and preparing them for microscopic study. The newer and faster squash technique involves squashing entire cells and studying their contents. Dyes that selectively stain various parts of the cell are used; the genes, for example, may be located by selectively staining the DNA of which they are composed. Radioactive and fluorescent tags are valuable in determining the location of various genes and gene products in the cell. Tissue-culture techniques may be used to grow cells before squashing; white blood cells can be grown from samples of human blood and studied with the squash technique. One major application of cytogenetics in humans is in diagnosing abnormal chromosomal complements such as Down syndrome (caused by an extra copy of chromosome 21) and Klinefelter syndrome (occuring in males with an extra X chromosome). Some diagnosis is prenatal, performed on cell samples from amniotic fluid or the placenta.
The-initial-proposal-of-the-structure-of-DNA-by-JamesThe initial proposal of the structure of DNA by James Watson and Francis Crick, which was …[Credits : Encyclopædia Britannica, Inc.]
Sex-linked-inheritance-of-white-eyes-in-Drosophila-fliesSex-linked inheritance of white-eyes in Drosophila flies.[Credits : Encyclopædia Britannica, Inc.]
Steps-involved-in-the-engineering-of-a-recombinant-DNA-moleculeSteps involved in the engineering of a recombinant DNA molecule.[Credits : Encyclopædia Britannica, Inc.]
Dolly-the-sheep-was-successfully-cloned-in-1996-by-fusingDolly the sheep was successfully cloned in 1996 by fusing the nucleus from a mammary-gland cell of …[Credits : Encyclopædia Britannica, Inc.]
Mendels-law-of-independent-assortment-The-example-here-shows-aMendel’s law of independent assortment[Credits : Encyclopædia Britannica, Inc.]
Mendels-law-of-segregation-Cross-of-a-purple-flowered-andMendel’s law of segregation[Credits : Encyclopædia Britannica, Inc.]
Punnett-square-diagrams-are-used-to-predict-all-the-possiblePunnett square diagrams are used to predict all the possible gene combinations that could result …[Credits : Encyclopædia Britannica, Inc.]
James Watson and Francis Crick revolutionized the study of genetics when they discovered the …[Credits : Acquired from Vast Video]
Specific segments of DNA are amplified (copied) in a laboratory using polymerase chain reaction …[Credits : Encyclopædia Britannica, Inc.]
Studying bacteria has lead to the relatively new science of genetic engineering.[Credits : Acquired from Vast Video]
Advantages of budding and grafting.[Credits : Acquired from Vast Video]
Mendel’s discovery of the fundamental laws governing the science of genetics.[Credits : Acquired from Vast Video]
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