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Simone Immler

Associate Professor


She researches breeding and sexual reproduction – with a particular focus on genetics and genomics.







Image for vimeo videos on Learning about hereditary diseases from zebrafish



Simone Immler is Associate Professor in Reproductive Biology in the School of Biological Sciences at UEA. She researches breeding and sexual reproduction – with a particular focus on genetics and genomics. She explores the genetic reasons for a specific individual sperm (among all the range of active sperm) to fertilise an egg. Her investigation is now looking at how to select a sub-sperm for in vitro assisted fertilisation technologies. Her work has initially involved the zebrafish – which produces large numbers of offspring and has similarities in some aspects of genetics with humans. An important earlier finding of her research was the demonstration of the long thought after trade-off between sperm size and number and how it may vary across taxonomic groups.

Simone has been awarded a Wallenberg Academy Fellowship in Sweden. She is the Reviewing Editor for eLife, an Associate Editor of Evolution and has been a Reviewing editor for the Journal of Evolutionary Biology. She is member of several bodies including the Society for the Study of Evolution (SSE) and the European Society of Evolutionary Biology (ESEB).

Areas of Expertise

Sexual ReproductionGenomicsReproductive BiologyGeneticsSperm


Wallenberg Academy Fellowship


Award for Outstanding Contribution, University of Sheffield



University of Sheffield

Ph.D., Evolutionary Biology


University of Basel

M.Sc., Evolutionary Biology



  • Member, Society for the Study of Evolution
  • Member, European Society of Evolutionary Biology
  • Member, Association for the Study of Animal Behaviour
  • Member, Society for Molecular Biology and Evolution

Media Appearances

Study finds ‘old’ sperm produces healthier offspring

Hindustan Times  online


Immler further added, “The sperm within an ejaculate vary not only in their shape and performance, but also in the genetic material that each of them carries. Until now, there was a general assumption that it doesn’t really matter which sperm fertilises an egg as long as it can fertilise it. But we have shown that there are massive differences between sperm and how they affect the offspring.”

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Offspring from older sperm are fitter and age more slowly

New Scientist  online


“I definitely do think this is relevant,” says team leader Simone Immler at the University of East Anglia in the UK. “We miss out on a lot of steps during artificial fertilisation technologies.”

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Women's bodies BLOCK weak sperm by creating a 'bottleneck' in the uterus where stronger swimmers force their way through

Daily Mail  online


Lead scientist Dr Simone Immler, from the University of East Anglia's School of Biological Sciences, said: 'We found that when we select for the longer-lived sperm within the ejaculate of male zebra fish, the resulting offspring is much fitter than their full siblings sired by the shorter-lived sperm of the same male.

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Not every sperm is sacred: Longer-lived sperm produce healthier offspring

Phys.Org  online


Dr Simone Immler, a European Research Council Fellow in UEA's School of Biological Sciences, said: "We found that selection for longer-lived sperm produced offspring which had increased chance of survival and performed better as adults than their siblings sired by non-selected control sperm. Thus, it is possible to get rid of the lower quality sperm within an ejaculate through selection on sperm performance.

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How Brexit is changing the lives of eight researchers

Nature  online


When the United Kingdom voted to leave the European Union on 23 June last year, the decision triggered a period of intense soul-searching and uncertainty, not least for a research community with strong and long-standing financial and social links to the continent. Worries about science funding, residency rights and even about racist attacks took root in laboratories across the country.

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Trade-off between somatic and germline repair in a vertebrate supports the expensive germ line hypothesis | Proceedings of the National Academy of Sciences


Limited resources and a possible trade-off between the repair and maintenance of the germ cells and growth and maintenance of the soma may explain the deterioration of the soma over time. Here we show that germline removal allows accelerated somatic healing under stress.

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Intrinsic post‐ejaculation sperm ageing does not affect offspring fitness in Atlantic salmon | Journal of Evolutionary Biology


Post‐meiotic sperm ageing, both before ejaculation and after ejaculation, has been shown to negatively affect offspring fitness by lowering the rate of embryonic development, reducing embryonic viability and decreasing offspring condition. These negative effects are thought to be caused by intrinsic factors such as oxidative stress and ATP depletion or extrinsic factors such as temperature and osmosis.

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Haploid Selection in “Diploid” Organisms | Annual Review of Ecology, Evolution, and Systematics


Evolutionary rates and strength of selection differ markedly between haploid and diploid genomes. Any genes expressed in a haploid state will be directly exposed to selection, whereas alleles in a diploid state may be partially or fully masked by a homologous allele. This difference may shape key evolutionary processes, including rates of adaptation and inbreeding depression, but also the evolution of sex chromosomes, heterochiasmy, and stable sex ratio biases.

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Effects of ovarian fluid on sperm traits and its implications for cryptic female choice in zebrafish | Behavioral Ecology


In polyandrous mating systems, females maintain the opportunity to bias male fertilization success after mating in a process known as cryptic female choice. Mechanisms of cryptic female choice have been described both in internal and external fertilizers, and may affect fertilization processes at different stages before, during, and after fertilization.

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The effects of male social environment on sperm phenotype and genome integrity | Journal of Evolutionary Biology


Sperm function and quality are primary determinants of male reproductive performance and hence fitness. The presence of rival males has been shown to affect ejaculate and sperm traits in a wide range of taxa. However, male physiological conditions may not only affect sperm phenotypic traits but also their genetic and epigenetic signatures, affecting the fitness of the resulting offspring.

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