Mendel has assumed trihybrid segregation in phenotype as a
combination of three independent monohybrid distributions of the features,
mathematically denoted in the formula (3:1)³. The general formula of
polyhybrid segregation according to phenotype is expressed as (3:1)ⁿ where n
is equal to the number of the pair of features, that are traced in discerning the
individual traits. The genotype distribution has the general formula (1:2:1)ⁿ.
With the increase of the number of hereditary features the picture get
more complicated and in some cases the results considerably deviate from
Mendel’s rules. Later on the studies in this field have registered many such
deviations that were not only explained but have also served as starting
points in the clarification of a number of problems in the structure and
interaction of genes. That is why the results from his classical experiments
are viewed as the basis of the chromosome theory and he, himself — the
acknowledged founder of genetics.
If Mendel’s rules of inheritance of the features are applied to man
whose karyotype contains 23 chromosome couples with an unknown
number of alleles in them, then their distribution according to phenotype
would surpass the fantastic quantity of 2²³ and the one of genotype — 3²³.
That is why each man has a unique hereditary pool of information with
exception of only the identical twins (see Dubinin, 1976).
Discovery of Nuclein and Elucidation of the Biological Role of Nucleic Acids
Section 2.5. In the second half of the XIX century one more great discovery
has been made. By 1868—69 the Swiss physiologist Friedrich Miescher has
isolated an unknown substance from the nuclei of pus cells called by him
nuclein. At this time he has been working in the field of organic chemistry in
Hoppe-Seyler’s Laboratory at the University of Tübingen (Germany) and was
studying the chemical composition of leucocytes. After that he has continued
his research on fish spermatozoa in which the nucleus accounts for over 90%
of the whole mass of the sperm cell.
Miescher’s studies on nuclein in the leucocytes have been published in
1871 and the ones on spermatozoa — in 1874. As in many other cases (for
example the Mendel’s case) his name would have also remained in oblivion
if were not his friends, in particular his uncle W. His (Anatomy professor in
Zürich), who organized the publication of a collected edition of his works
and letters after his death (Die histochemischen und physiologischen
Arbeiten von Friedrich Miescher, 2 vols. F.C.W. Vogel, Leipzig, 1897).
Miescher has pondered the role of nuclein in the fertilization of fish but
has let the “golden fish” swim freely in the waters of the Rhine river where by
the help of fishermen he has ensured material for his studies. He has
displayed a physicochemical approach to the problem and has demonstrated
a dubious attitude towards the nuclein-chromosomes connection predicted by