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  Introduction to Genetics, Biology tutorial

History of Genetics:

For thousands of years, humans have performed as agents of genetic selection, by breeding offspring with preferred characteristics. All domesticated animals (dogs, horses, cattle) and food crops (wheat, corn) are result.

Offspring look like parents (or do not) in bewilderingly complex methods.  That is due to individuals in nature have several genes, and several different versions (alleles) of every gene.  Consider these three individual orchids:

In 1866, Gregor Mendel discovered independent assortment of features, dominant and recessive expression. Characteristics appear in pairs; divide independently in gametes; recombine in pairs, in offspring. But Mendel's effort was lost.  Only in past century humans learned primary mechanisms of heredity:

How and why organisms look like their parents; and how inherited information functions to make organisms look and behave as they do.

1902: Walter Sutton and Theodore Boveri, utilizing dyes synthesized by German organic chemistry industry, observed that colored bodies in cells behaved in ways parallel to hypothetical agents of heredity suggested by Mendel. These bodies were known as chromosomes.

1905: Nettie Stevens observed in Tenebrio beetles that every pairs of homologous chromosomes are same size, except for one pair that determines sex -- X, Y.

1909: Thomas H. Morgan correlates X chromosome with sex-linked inheritance of white eye feature in Drosophila -- a strain of flies seen by the undergraduate lab assistant, cleaning out old bottles of flies in Morgan's lab. Morgan went on to make several significant discoveries in fly genetics and linkage analysis which apply to every diploid organisms.

1941: Beadle and Tatum determined in Neurospora that each gene encodes one product (protein). (Later, we learned that RNA can be the product, not always transcribed to protein; for instance, a ribosomal RNA.)

1944: Oswald Avery recognized DNA as genetic material. Pieces of DNA can transfer genes in bacteria cells, and transform them genetically.

1953: Rosalind Franklin and Maurice Wilkins illustrated that DNA is double helix.

Thomas Watson and Frances Crick found structure of base pairs that allow replication producing two identical daughter helices.

1961: Jacob and Monod figured out regulation of lac operon.

1960's: Barbara McClintock discovered transposable elements in corn; later determined in bacteria and animals.

1970: Temin and Balitimore discovered reverse transcriptase in retroviruses; the enzyme later utilized to clone genes based on RNA encoding product.

1977: Maxam, Gilbert, Sanger, others -- developed ways to sequence DNA.

1981: First transgenic mammals were prepared.

1987: Kary Mullis invented polymerase chain reaction (PCR), employing thermostable enzyme from thermophilic bacterium found by Thomas Brock at geyser in Yellowstone. Mullis sold procedure to the pharmaceutical company, and earned very little. Brock did not earn cent.

1995: First bacterial genome sequence, Haemophilus influenzae, was totally determined.

1996: Ian Wilmut cloned lamb Dolly from adult mammary gland tissue.

2000: Completion of human genome

2005: Principles for the European GMO-free regions were formally laid down in February in Florence during the Network's 3rd Conference with the subscription of a joint document called "Charter of Florence".

2006: Pig was engineered to generate omega-3 fatty acids through addition of the roundworm gene

2008: European Commission authorized GM maize GA21 for feed and food use and for import and processing. GA21 isn't approved for cultivation in EU.

2010: Amflora was accepted for industrial applications in European Union by European Commission. Amflora is the genetically altered potato result of two decades of research efforts. Amflora potato is chosen for special starch properties utilized in paper making and adhesives.

Importance of genetics:

Gene is a director of our bodies. Genes stipulates and guides building and make up of our cells. Gene are made out of DNA, one line of DNA can have thousands of genes. Genes control and make part of bodies work.

As well as genes determining sex, or whether we are female or male, every part of our bodies has its own body pattern. Arms and legs may have similar body patterns as it is all mostly bone and muscle apart from shapes which is different. Embryo grows differently on arms and legs because works of different genes in arms and legs, these genes are known as homeotic genes.

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