3 The New York Years (1931–1953)

A Modern Unified Theory of Evolution 187
Dear Dr. Mayr:
Many thanks for your kind letter of Nov. 7th, which is so highly flattering to
me, and to which I certainly want to reply.
TheneedforareconciliationoftheviewsoftaxonomistsandgeneticistsIfeel
very keenly, but it seems to me that all what is to be reconciled are just the
viewpoints, since I do not perceive any contradictions between the facts secured
in the respective fields. Of course, this is a big “just”. So far geneticists
appear to think that they need not pay any attention to what taxonomists are
doing, and vice versa. To my mind this is the root of the trouble. Probably no
less than 75% of geneticists still believe that there is nothing in particular to
be gained from studies on the races of wild animals as compared with races in
bottles. You and myself will probably have no disagreement as to the absurdity
of this view.
On the other hand, I also fail to see the difference between the “qualitative”
and “quantitative.” May be I am blind, but the only distinction which is of
consequence is that the former are easy to study, and the latter are notoriously
difficult. Of course, there are geneticists which agree with you (e.g., Castle).
Canyou,however,nameanyonewhogotanywhereinparticularwiththis
distinction?
TheflyIamworkingwith(Drosophila pseudoobscura)isasfavorableamaterial
for studies on geographic variation as its more widely known relative is
unfavorable (Dr. melanogaster). If nothing unexpected happens, I hope to be
able to furnish you in the future with some more information on the subject.
In turn, I feel the deficiency of my knowledge of the studies in the same field
by taxonomists; our library here has no taxonomic literature at all. Hence,
I would like to conclude this my discourse with a request to you to include my
name in your mailing list. I think you have some of my older reprints, and in
a few days I shall send you another bunch.
Sincerely yours, Th. Dobzhansky.
Both Dobzhansky and Mayr followed a continental European tradition in evolutionary
research and systematics studying geographical changes of populations
leading to speciation and macroevolution, i.e., the “horizontal” (geographical)
dimension of evolution. Other representatives of this tradition were Plate,
Stresemann, Rensch, Stegmann, Mertens, Reinig, Wettstein, Baur, Philipchenko,
Timoféeff-Ressovsky, and, prior to 1933, Goldschmidt. This list includes not only
evolutionary systematists but also several continental geneticists (see also Harwood
1993: 129–137). On the other hand, an Anglophone tradition emphasized
the study of adaptive genetic change in populations through time, i.e., the “vertical”
dimension of evolution, indicated by the names of T.H. Morgan, H.J. Muller,
S. Wright, R. A. Fisher and J. B. S. Haldane. Of course this distinction is not always
clear-cut. Several scientists in North America and Britain also studied problems
of diversity and the “horizontal” aspects of evolution like F. Sumner, L.R. Dice,
D. S. Jordan, J. Grinnell, E. B. Poulton, E. B. Ford, and Karl Jordan (Mayr 1992i,
1993a).