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Genetics Genetics is scientific study of transmission of physical, behavioral and biochemical traits to the offspring. The word Genetics was coined by a British scientist William Bateson in 1906. Because of scientific research it was possible to determine the mechanism of inheritance in the offspring of the sexually reproducing organisms. Some of the differences and similarities between parents and offspring recur from generation to generation in repeated patterns. The investigation of these patterns has led to some of the most exciting discoveries in modern biology. The
science of genetics began in 1900. The first observation of genetics
can be attributed to the work of the Austrian monk Gregor
Mendel, which was published in 1866
but was virtually ignored. Mendel presented his observation on working
with garden peas. Mendel described the patterns of inheritance in
terms of seven pairs of contrasting traits that appeared in different
pea plant varieties. He observed that the traits were inherited as
separate units, each of which was inherited independently of the
others. His observation was that each parent has a pair of unit
but contributed only one unit from the pair to its offspring. This
unit was later given the name Genes. Formulating his first principle (the law of segregation), Mendel stated that genes normally occur in pairs in the ordinary body cells, but segregate in the formation of sex cells (eggs or sperm), each member of the pair becoming part of the separate sex cell. When egg and sperm unite, forming a gene pair, the dominant gene (tallness) masks the recessive gene (shortness). On interbreeding the first hybrid tall peas Mendel found that the second generation turned out in a ratio of three tall to each short offspring. He formulated that the genes paired into AA, Aa, and aa ("A" representing dominant and "a" representing recessive). He found that the self-pollinated AA bred true to produce pure tall plants, that the aa plant produced pure dwarf plants, and that the Aa, or hybrid, tall plants produced the same three-to-one ratio of offspring. From this Mendel observed that the hereditary units did not blend and remained unchanged from one generation to the nexet. Thus his second principle was - the law of independent assortment -- the expression of a gene for any single characteristic is usually not influenced by the expression of another characteristic. The
Medel's Laws became the basis for modern genetics.
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