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The Early Days of Yeast Genetics edited by Michael N. Hall and Patrick
Linder, Cold Spring Harbor Laboratory Press, pp 477, $75

With modern eyes to see, yeasts are ideal organisms for studying genetics
– they grow simply and are easily manipulated. Take a haploid cell (one
containing a single set of chromosomes) of the brewer’s yeast, Saccharomyces
cerevisiae. It can reproduce asexually by budding or it can get together
with a cell of the opposite mating type to give a diploid cell. This too
may reproduce asexually, forming a diploid population. Alternatively, it
may undergo meiosis, producing a sac-like structure, the ascus, containing
four ascospores which then germinate into further haploid cells.

But our knowledge of these and other genetic properties of yeast did
not emerge without difficulty, confusion and controversy. That is the story
told here by some 30 authors, many of whom have played central roles in
the painstaking compilation of our picture of yeast genetics, from early
studies on recombination and mutation to much later work on the cell cycle
and molecular biology. This is a splendid book that can be highly recommended
as an atypically vivid portrait of science in action. I have just one caveat:
the title obscures the fact that several of the later chapters come very
close to present-day developments.

Yeast genetics certainly got off to a vigorous start in the hands of
its two principal pioneers, Ojvind Winge of the Carlsberg Laboratory in
Copenhagen and Carl Lindegren of the University of Southern Illinois, Carbondale.
Where Winge saw his yeast behaving according to strict Mendelian principles,
Lindegren found non-Mendelian segregations. Where Winge was solid and thorough,
Lindegren was imaginative – and sometimes a little sloppy in his publications.

Each certainly made many major contributions to the nascent science
of yeast genetics. For example, the Dane developed reliable instruments
to dissect out ascospores and established that yeasts alternated between
haploid and diploid phases. The American discovered the mating type system
of yeast and ‘gene conversion’ which, though based initially on faulty
reasoning, later proved to be central to the now well-recognised process
of recombination. But in all of this and much more besides the two pioneers
were contestants rather than collaborators. As Robert Mortimer observes,
their disagreements were so extensive that it was amazing that yeast genetics
got off the ground at all.

Nevertheless, several decades later, yeast occupies a place in genetic
science as significant as that of Drosophila or Escherichia coli, and Hall
and Linder have assembled a tome as comprehensive and colourful as John
Cairns, Gunther Stent and James Watson’s Phage and the Origins of Molecular
Biology (Cold Spring Harbor Laboratory Press, 1992). With the exception
of Boris Ephrussi’s 1953 essay on ‘nucleo-cytoplasmic relations in microorganisms’
and a reminiscence by Herschel Roman from the Annual Review of Genetics
1986, all the chapters have been specially written. There is much sheer
enthusiasm, lots of flavour of the atmosphere of particular laboratories,
and the delightful embellishment of many individual and group photographs
taken at gatherings large and small over the years.

One particular delight is the reminiscence by Gerald Fink from the Whitehead
Institute in Cambridge, Massachusetts, of the Cold Spring Harbor Yeast Course
which he and Fred Sherman taught every summer from 1970 until 1987. Housed
in the stifling conditions of the Davenport Laboratory, a former boathouse
on Long Island, it brought together groups of students to learn the exacting
and often frustrating techniques of yeast genetics.

Pestered by the bites of sand fleas spawned by the heat and humidity,
and with their nutrient agar ever threatened by contaminating white moulds,
the students used elderly microscopes and micromanipulators to dissect out
their ascospores. To make matters worse, Sherman would deliberately give
them a strain that sporulated terribly, while the inadequate air-conditioning
pumps thumped so strongly that delicate manipulation was out of the question.

The theory was, presumably, that anyone capable of overcoming all those
difficulties would be bound to do well in more salubrious surroundings.
At the same time, the ramshackle environment seemed to enhance the pioneering
spirit. As Fink writes: ‘There was the shared sense that we, both the students
and the teachers, were standing on the threshold of a gold lode – we knew
that yeast had great potential and we were eager to set about mining it.’

In much more recent times, in March 1992, it was Gerald Fink who reported
that S. cerevisiae can grow not only as the familiar oval cells but also
in a filamentous form. Publication of that discovery came just after European
collaborative efforts culminated in the announcement of the entire sequence
of chromosome 3 of the same organism. The contrast was instructive. Yeast,
the subject of the latest sophisticated molecular genetics, had also revealed
for the first time a mode of behaviour that might have been expected to
have been recognised long, long ago. Perhaps we are still in the early days
of yeast genetics.

Bernard Dixon is European editor of Bio/Technology.