Sperm evolution across reproductive and fertilization modes

Main funder

Funder's project number: 335759

Funds granted by main funder (€)

  • 197 784,00

Funding program

Project timetable

Project start date: 01/04/2021

Project end date: 31/03/2023


First observed 350 years ago, spermatozoa diversity was soon recognized to be an evolutionary conundrum.
However, most studies addressing these questions have looked at taxonomic groups where the variation
in sperm is but a fraction, mostly showing quantitative (relative component size) vs. qualitative (component
type and presence/absence) interspecific difference. Not surprisingly, many questions remain unanswered.
Tardigrada are uniquely suited taxonomic phylum to conduct such research, by having unparalleled
diversity in sperm design but providing a view of reproductive evolutionary forces, less confounded
by huge phylogenetic spread. I propose an ambitious, forward-looking, yet attainable program, that
takes advantage of the exceptional opportunities the biology of this groups offers for present and future
(evolutionary) research. Tardigrades are small, transparent animals, with diverse reproductive biology:
there are hermaphroditic and bisexual species, the latter with or without sperm storage; both internal and
external insemination occurs. They are found globally, and terrestrial taxa can survive extreme conditions
by undergoing reversible cryptobiosis (ametabolic state). This project will use a combination of research
methods to investigate sperm evolution by comparing sperm form and function across the wide range of
selective forces: (i) run comparative analyses using both published (design) and new (function) sperm traits;
(ii) conduct experimentally controlled sexual interactions to monitor of mating behaviour and genetically
score paternity; (iii) use modern imaging techniques for in vivo and/or in toto monitoring of sperm function
from the testis to the egg across the wide range of insemination/fertilization paths. This project offers high
potential for immediate and significant contributions to some, so far fundamentally unanswerable, longstanding questions in reproductive evolution. Their peculiar appearance, their incredible biological feats (e.g.
survive outer Space) and their consequent promising role in medical applications (x-ray resistance), make
tardigrades the ultimate study organism for academic and societal impact purposes. This project will create
their first research centre in Finland.

Principal Investigator

Primary responsible unit

Last updated on 2021-17-03 at 12:06