Physiological techniques, directed at exploring functional properties or organisms, are also used in genetic investigations. In microorganisms, most genetic variations involve some important cell function. Some strains of one bacterium (Escherichia coli), for example, are able to synthesize the vitamin thiamin from simple compounds; others, which lack an enzyme necessary for this synthesis, cannot survive unless thiamin is already present. The two strains can be distinguished by placing them on a thiamin-free mixture: those that grow have the gene for the enzyme, those that fail to grow do not. The technique also is applied to human cells, since many inherited human abnormalities are caused by a faulty gene that fails to produce a vital enzyme; albinism, which results from an inability to produce the pigment melanin in the skin, hair, or iris of the eyes, is an example of an enzyme deficiency in man.
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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