GNN - Genome News Network  
  Home | About | Topics
Introduction | Overview
2004 Rat
2002 Mouse
2001 30,000 Genes
2000 The Human Genome
1999 Fruit Fly
1998 Worm
1996 An Extremophile
1996 Yeast
1995 Haemophilus
1991 Venter
1986 Human Genome
1986 Hood
1983 Mullis
1978 Botstein
1977 Gilbert & Sanger
1973 Boyer & Cohen
1972 Berg
1970 Smith
1970 Temin & Baltimore
1969 Beckwith
1967 Weiss & Green
1961 Jacob & Monod
1961 Nirenberg
1960 mRNA
1957 Crick
1956 Kornberg
1953 Crick & Watson
1950 Chargaff
1944 Avery
1943 Delbruck & Luria
1941 Beadle & Tatum
1934 Bernal
1927 Muller
1913 Sturtevant
1910 Morgan
1909 Johannsen
1908 Garrod
1904 Bateson
1902 Boveri & Sutton
1900 Rediscover Mendel
1888 Boveri
1882 Flemming
1876 Galton
1869 Miescher
1866 Mendel
1859 Darwin

 Printer Friendly
Genetics and Genomics Timeline
Theodor Boveri (1862-1915) establishes the individuality and continuity of chromosomes

Amidst much interest in cell structure and development, in 1887 Theodor Boveri began investigating chromosomes. He was inspired by the first complete description of them two years earlier, together with hints that they might convey something of the secret of heredity. He wanted to discover, he later wrote, "those processes whereby a new individual with definite characteristic is created from the parental generative material." In studies published from 1887 to 1890, Boveri made several key observations about the way that chromosomes behave during cell division.

Theodor Boveri

Chromosomes remain organized and individual structures through the process of cell division. Boveri worked with eggs of Ascaris megalocephala, a parasitic worm with just four chromosomes, publishing an exhaustive study in 1888. During the "interphase" just before cell division, the chromosomes could not be individually distinguished—indeed, they seemed to disappear. But Boveri, using the light microscope, showed that the same arrangement and shape of chromosomes could be found in the daughter cells both before and after mitosis, or somatic cell division. Under his interpretation, chromosomes were highly organized units. Because inheritance demands continuity from generation to generation, Boveri began to suggest that chromosomes were involved in heredity.

Sperm and egg contribute the same number of chromosomes. Boveri went on to work with sea urchin eggs. He discovered that, during fertilization, the nuclei of sperm and egg do not fuse, as previously thought. Rather, each contributes sets of chromosomes in equal numbers. With this study, published in 1890, Boveri provoked great interest in the chromosomes; but his idea that they were central to inheritance frequently met with skepticism.

Boveri's early studies set the stage for his hypothesis, to be put forward at the turn of the twentieth century, after the rediscovery of Mendel's laws, that chromosomes transmit hereditary characteristics.

A professor of zoology and comparative anatomy at the University of Würzburg, Boveri combined exceptional observational skills with great theoretical acuity. He possessed a willingness to advance controversial hypotheses and defend them vigorously. Toward the end of his life, in 1914, he made the provocative and far-sighted suggestion that abnormal chromosomes might be responsible for cancerous tumors.

Baltzer, F. Theodor Boveri. Science 144, 809-815 (1964).

Back to GNN Home Page