Research Focus
Why Sex?
This simple question is a
major conundrum in evolutionary biology.
major conundrum in evolutionary biology.
“
The central question is as follows: what selective forces maintain sexual reproduction and genetic recombination in nature?
Sex has many costs. Demographic costs of males, transmission costs, costs of mating (predator exposure and STDs), and so on. But why are then the huge majority of organisms mixing genomes through sexual reproduction involving males and females, when there is the straight-forward way of just producing asexual (parthenogenetic) females? What are the profound advantages of sex that offset its costs in most organisms?
READ MORE HERE
READ MORE HERE
One way to find out what the big benefits of costly sex are, is to compare sexuals with their asexuals relatives to identify the differences. In that way theoretical predictions can be empirically tested. Nowadays this happens via the generation and analyses of (population) genomic data.
Ancient Asexual Scandals In our lab, we focus on animals that persisted in the absence of sex for millions of years. Normally, asexual lineages are thought to be driven to extinction because of ineffective selection. However, many species of asexual oribatid mites are able to adapt, diversify and get rid of harmful mutations. They are evolutionary scandals, because they escape their fate of extinction. Such incidences of ancient asexuals are important to study, because identifying the singularities that allow for their evolutionary persistence through time will help vice versa to identify the benefits of sex. |
“All you really need to know for the moment is that the universe is a lot more complicated than you might think, even if you start from a position of thinking it’s pretty damn complicated in the first place." — Douglas Noel Adams
Projects we are working on right now
Meselson effect
In asexual mites, do intra-individual haplotypes diverge over time (Meselson effect)?
-> It seems so!
-> It seems so!
Speciation
How do asexuals speciate? What are genomic features of speciation? Do asexual species occupy ecologically different niches and are these signatures found in genomes?
Escape extinction
How can asexual mites maintain effective selection? Because of large and stable populations and/or effective repair mechanisms?
Asexual Innovation
Is plasticity a feature of asexual genomes? Are they more free to evolve novelty? How do sexual and asexual genomes differ?
Single individuals
We use new sequencing technologies for generating chromosome scale genomes from very little DNA amount of single individuals
Sex determination
How do mites produce males and females? Are there sex chromosomes?
MSc and BSc theses
We are open for own project ideas.
Outreach
We communicate our results with the public and try to spark the excitement for science in kids.
Meet our team
This is the core research team.
- Jens BastPrincipal InvestigatorJens takes care of the big picture. He develops the direction of research, takes care of scientific needs of group members and the labs funding.
- Simo (Mohammed Errbii)PostDocSimo is interested in genome evolution on the population scale. He looks into sexual and asexual mites and nematodes.
- Shan GaoPhD student and Bioinfo lead高山 is interested in the bioinformatic side of things. He analyzes the genomic landscapes of asexuals and sexual relatives and identifies what makes them special.
- Nadège GuiglielmoniPostdoctoral researcherNadège is interested in assembling tricky animal genomes to chromosome and haplotype level using long reads and Hi-C, and she develops tools for assembly. She works in the Sex Lab and in the Worm Lab in a joint research effort about consequences of asexuality.
Our publications (selection)
Short description of selected published papers
The Meselson effect in mites
Haplotype divergence supports long-term asexuality in the oribatid mite Oppiella nova.
Brandt et al. 2021 PNAS
https://www.pnas.org/content/118/38/e2101485118
Brandt et al. 2021 PNAS
https://www.pnas.org/content/118/38/e2101485118
What are common features of asexual genomes?
Genomic Features of Parthenogenetic Animals
Jaron et al. 2021 J Hered
https://doi.org/10.1093/jhered/esaa031
Jaron et al. 2021 J Hered
https://doi.org/10.1093/jhered/esaa031
TEs are benign in asexuals
Asexual reproduction reduces transposable element load in experimental yeast populations
Bast et al. 2019 eLIFE
https://elifesciences.org/articles/48548
Bast et al. 2019 eLIFE
https://elifesciences.org/articles/48548
Selection works better for asexual mites than sexuals
Effective purifying selection in ancient asexual oribatid mites
Brandt et al. 2017 Nat Commun
https://www.nature.com/articles/s41467-017-01002-8
Brandt et al. 2017 Nat Commun
https://www.nature.com/articles/s41467-017-01002-8
Mutation accumulation and arrested gBGC in asexual Timema
Consequences of Asexuality in Natural Populations: Insights from Stick Insects
Bast et al. 2018 MBE
https://doi.org/10.1093/molbev/msy058
Bast et al. 2018 MBE
https://doi.org/10.1093/molbev/msy058
TEs load in nature is not influenced by reproductive mode
No Accumulation of Transposable Elements in Asexual Arthropods
Bast et al. 2015 MBE
https://doi.org/10.1093/molbev/msv261
Bast et al. 2015 MBE
https://doi.org/10.1093/molbev/msv261
Contact
If you want to discuss science with us, you can find us here.
Institute for Zoology, University of Cologne
Zülpicher Str 47b, 50674 Köln
Phone: +49 221 470 3119
E-mail: jbast [at] uni-koeln.de
We are located in the Biocenter.
The nearest trainstation is Köln Süd
Zülpicher Str 47b, 50674 Köln
Phone: +49 221 470 3119
E-mail: jbast [at] uni-koeln.de
We are located in the Biocenter.
The nearest trainstation is Köln Süd
