1839- cell theory Schleiden & Schwann

1859- particulate inheritance Mendel

1877- chromosomes observed Flemming

1900- blood groups discovered Landsteiner

1903- chromosomes carry genes Sutton

1908- inheritance of blood groups Ottenburg

1910- 1st genetic clinic- USA Davenport

1946- 1st genetic clinic- UK Roberts

1953- DNA chromosomes in man Watson & Crick

1960- 1st chr.. abnormality in man Tjio/Levan

prenatal sexing Riis & Frucks

genetic code Nienenberg

1970- 1st gene synthesised in vitro Khorana

1979- in vitro fertilisation Edward's & Steptoe

1985- genetic fingerprinting Jeffrey's

1993- 1st gene therapy Numerous authors

1. mutations- changes in one or more bases in a chromosome. mutations may be¨-

-dominant (gene is expressed is the next generation)

- recessive (several generations for expression)

2. aneuploidy- changes in the number of chr..s within a cell. normal diploid nu

Ascaris (threadworm) has 2 or 4 chr.

mber is 46. haploid is 23. any deviation has serious consequences for the individual.

Some topics in this essay:
Edward's Steptoe, TDY SDG, XX XY, X-chr Barr, FRS MRC, Murray Barr, Schleiden Schwann, Riis Frucks, Watson Crick, UK Roberts, autosomes plus, 1st genetic clinic-, male female, genetic clinic-, determining gene, normal diploid, barr bodies, 47 chr, 1st gene, cell division, germ cells,