Download A “tail” of two sperm, and other stories 9th Biology of Spermatozoa

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TRAVEL REPORTS
A “tail” of two sperm, and other stories
9th Biology of Spermatozoa Meeting
14th – 18th September 2007, Losehill Hall, UK
Steve Ramm . University of Liverpool
Leeuwenhoek, gave a talk based on his book “The
Egg and Sperm Race”. This was a sweeping
historical survey encompassing everything from
Aristotle to Assisted Reproduction, describing
the best (and worst) achievements of several
thousand years of studying reproductive biology,
and reminded us all of the giants upon whose
shoulders we seek to stand. With the audience
suitably enthused, the rest of the meeting
comprised over fifty talk and poster
presentations, just a few of which I have space to
mention here.
Delegates at the Biology of Spermatozoa 2007 meeting.
T
he modern era in sperm
biology began in 1677
when the pioneering
microscopist Antoni
Leeuwenhoek plucked up the
courage to write to the Royal
Society and report the
surprising ‘animacules’ he’d
discovered in his semen. This
not being the sort of discovery
one might make by accident, he
delicately explained that his
subject had been “the excess
which Nature provided me in
my conjugal relations”.
Nevertheless, to guard against
any perception of
unseemliness, he took the
unusual step of writing his
letter in Latin. These days, of
course, things are rather
different, and we sperm
biologists will tell anyone and
The first scientific plenary of the conference was
delivered by Rhonda Snook (University of
Sheffield, UK) on sperm heteromorphism in
everyone who’ll listen about the Drosophila. As in many other animal groups,
male Drosophila produce two types of sperm,
often weird but always
only one of which is capable of fertilization. The
wonderful world of gametes.
Every two years, the Biology of obvious, and unresolved, evolutionary puzzle in
this is why they should bother with the other,
Spermatozoa meeting,
organised by Tim Birkhead and non-fertilizing type. One intriguing possibility,
the audience was told, is that they act as
Harry Moore of the University
of Sheffield, provides a window ‘sacrificial sperm’, being killed by females but
thereby increasing the likelihood that their
on that world, and is the
fertilization-capable kin will make it to the
premier forum for discussing
female’s sperm storage organs.
evolutionary aspects of
reproduction research. This
Sticking for the moment with Drosophila,
year’s meeting, the ninth since
199 and held at Losehill Hall in another highlight was the plenary given by
the Peak District National Park, Mariana Wolfner (Cornell University, USA),
revealing the exquisite detail to which she and
was no exception.
others have mapped the myriad effects of male
seminal fluid proteins (known as ‘Acps’) upon
The conference began, as I
female reproductive physiology and behaviour.
have, with a little historical
Every minute of the talk felt like the distillation
perspective. Matthew Cobb
(University of Manchester, UK), of weeks, months and probably even years of
painstaking research; the result was a master
from whom I’ve borrowed the
class on what I hesitate to describe as Prof.
above story about
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TRAVEL REPORTS
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Wolfner’s seminal contribution
to the field.
vanguard of this revolution has
been Steve Dorus (University of
Bath, UK), who spoke on the
I’m sure in many cases inspired proteomic and genomic
techniques that can
by the example of Drosophila
increasingly be brought to bear
Acps, a noticeable trend at the
on evolutionary questions,
meeting was the increasing
illustrated by his own work to
emphasis on seminal fluidelucidate the Drosophila
mediated effects in sexual
selection across a wide range of melanogaster sperm proteome.
The importance of a molecular
animal groups (the conference
perspective was also
heard about studies in social
emphasised by the final plenary
insects, mosquitoes, birds and
speaker of the conference,
mammals, and there are
Victor Vacquier (University of
undoubtedly many more
California San Diego, USA),
underway). For example,
who provided a comprehensive
Tomasso Pizzari (University of
overview of his lab’s groundOxford, UK) delivered some
fascinating early results from a breaking work on the molecular
evolution of gamete recognition
study in domestic fowl of the
proteins in marine
potential for seminal fluid to
act differentially on self versus invertebrates, principally
abalone and sea urchins. This
non-self sperm. The project
work was among the first to
arises from the paradox that a
major property of seminal fluid establish the unusually rapid
evolution of reproductionmay be to damage sperm, a
related genes compared to most
strategy which only really
seems to make sense if it can be other parts of the genome, and
continues to set the standard.
directed at the sperm of one’s
Work on vertebrate fertilization
rivals in contests over
lags in many respects some way
paternity. Work by Charlie
behind, but adopting a rather
Cornwallis from the same
different approach Eduardo
group suggests that seminal
Roldan (Museo Nacional de
fluid may also be responsible
Ciencias Naturales, Spain)
for social status-dependent
presented data on asymmetries
variation in ejaculate quality.
My own contribution also came in reciprocal cross-fertilization
in this area, when I spoke about experiments in closely related
rodent species that are
the molecular evolution of
attempting to uncover the
mammalian seminal fluid
degree to which sperm
proteins, and in particular the
rodent mating plug protein SVS competition and sexual conflict
may be responsible for the
II. In fact, another unifying
theme of the conference for me rapid divergence of
was this increasing integration reproductive proteins.
of a molecular perspective into
studies of sperm competition
An earlier molecular revolution
in behavioural ecology, that of
and sexual selection research.
DNA fingerprinting (and the
One of the scientists at the
consequent ability of researchers to assign
paternity and thus determine the outcome of
sperm competition), continues to lead to
important discoveries. This was amply
illustrated at the meeting, for example by Mats
Olsson’s (University of Wollongong, Australia)
analysis of male colour morphs in the Australian
painted dragon lizard Ctenophorus pictus, or by
Marco Demont’s (University of Zürich,
Switzerland) study of sperm sorting in yellow
dung flies, Scathophaga stercoraria. Paternity
data will also shed light on the fascinating
pattern of reproductive investment reported by
John Fitzpatrick (McMaster University, Canada)
in the cooperatively breeding cichlid fish
Neolamprologus pulcher, in which helper males
appear to be reproductively suppressed but then
rapidly and dramatically increase sperm
production if the dominant breeder male is
removed from their group. All of these examples
highlight the value of measuring how phenotypic
diversity translates into reproductive success, in
order to understand the complexities of natural
populations.
I’ll end with two final thoughts that arise from
the conference: one, that things are often much
more complicated than one might at first expect
(neatly illustrated by Joachim Wistuba (Institute
of Reproductive Medicine, Muenster, Germany)
and Stefan Luepold (University of Sheffield, UK),
both of whom gave talks on the important but
often ignored intricacies of testicular
architecture); and two, that they are often also
more beautiful (who would have thought that
watching Drosophila sperm heads flit from one
female sperm storage organ to another – as was
shown by Scott Pitnick (Syracuse University,
USA) – could be quite so captivating? Or that, as
demonstrated by David Woolley (University of
Bristol, UK), and explaining my title, when two
sperm meet each other they put on a display of
synchronised swimming equal to anything you’re
likely to see at the Olympics? Capturing the
complexity and beauty of sperm biology is what
this meeting does best and long may it continue.
My thanks to the organisers of BoS 9 for a
wonderful meeting, and to the Genetics Society
for the funds that enabled me to attend.
www.genetics.org.uk . 25