Classical Genetics Between 1900 and 1953

Johann Gregor Mendel


Classical Genetics Between
1900 and 1953
In 1906, the English biologist William Bateson
(1861–1926) proposed the term genetics for the
new biological field devoted to investigating
the rules governing heredity and variation.
Bateson referred to heredity and variation
when comparing the similarities and differences,
respectively, of genealogically related organisms,
two aspects of the same phenomenon.
Bateson clearly recognized the significance of
the Mendelian rules, which had been rediscovered
in 1900 by Correns, Tschermak, and
DeVries.
The Mendelian rules are named for the
Augustinian monk Gregor Mendel (1822–
1884), who conducted crossbreeding experiments
on garden peas in his monastery garden
in Brünn (Brno, Czech Republic)well over a century
ago. In 1866, Mendel wrote that heredity is
based on individual factors that are independent
independent
of each other (see Brink and Styles, 1965;
Mayr, 1982). Transmission of these factors to
the next plant generation, i.e., the distribution
of different traits among the offspring, occurred
in predictable proportions. Each factor was responsible
for a certain trait. The term gene for
such a heritable factor was introduced in 1909
by the Danish biologist Wilhelm Johannsen
(1857–1927).
Starting in 1902, Mendelian inheritance was
systematically analyzed in animals, plants, and
also in man. Some human diseases were recognized
as having a hereditary cause. A form of
brachydactyly (type A1, McKusick 112500) observed
in a large Pennsylvania sibship by W. C.
Farabee (PhD thesis, Harvard University, 1902)
was the first condition in man to be described as
being transmitted by autosomal dominant inheritance
(Haws and McKusick, 1963).
In 1909, Archibald Garrod (1857–1936), later
Regius Professor of Medicine at Oxford University,
demonstrated that four congenital metabolic
diseases (albinism, alkaptonuria, cystinuria,
and pentosuria) are transmitted by autosomal
recessive inheritance (Garrod, 1909).
Garrod was the first to recognize that there are
biochemical differences among individuals that
do not lead to illness but that have a genetic basis