Welcome to the new students!

Great to welcome our new (and largest ever) cohort of students last week with a trip to Treborth Botanic Gardens!

Now I’d better actually write some lectures…

New paper published!

How do genes on sex chromosomes evolve in Timema?

In our new paper, we identify and examine patterns of sequence evolution and gene expression on the X chromosome across five Timema species.

Overall we find consistent evidence for relaxed selection on the X and complete dosage compensation in somatic tissues but not the reproductive tracts.

Interestingly, we also find that genetic diversity is much lower on the X than expected (X to autosomes ratio of 0.19 to 0.48, much lower than the expectation of 0.75), which may be due to a combination of a lower effective recombination rate on the X and population bottlenecks.

Finally, we find that dosage compensation in Timema seems to be due to the upregulation of the X chromosome in males. This mechanism is also common to all other XX/XY or XX/X0 insect systems yet studied, suggesting that this mechanism may be universal for insect species with heterogametic males.

MEEB biannual meeting

MEEB-ers assemble!

Yesterday we held the MEEB biannual meeting to discuss updates and problems, and to assign roles to group members.

Surprisingly fun and great to meet with (almost) all the MEEB members in person!

New paper published!

Does developmental strategy influence the development of sex-biased gene expression?

In our new paper, (led by PhD student Jelisaveta Djordjevic) we take a first look at this question in insects by examining sex-biased gene expression across development in a hemimetabolous insect (Timema californicum). We find that sex-biased gene expression develops more gradually and to a lesser extent than in holometabolous insects.

This suggests that hemimetabolous development may constrain the evolution of sex-biased gene expression, but we need more developmental gene expression studies in hemimetabolous insects to verify this!

New preprint – Facultative parthenogenesis in Timema

Does obligate parthenogenesis evolve via facultative parthenogenesis?

In our new preprint (led by ChloĆ© Larose and Guillaume Lavanchy) we describe facultative parthenogenesis in several populations of Timema douglasi – a species previously thought to be obligately parthenogenetic. Parthenogenetic offspring seem to be produced in a similar way as in obligate parthenogenetic populations (via automixis), suggesting that obligate parthenogenesis (in Timema at least) may evolve via a facultative parthenogenetic stage.

New paper, new position.

Last week our paper on the convergent consequences of parthenogenesis on Timema genomes came out, nicely marking my last full day in Lausanne! Work on this paper spanned my entire 6 (SIX) year stay in Lausanne, through Brexit, Covid, and other big life changes, so very nice to see it finally out (see SIB press release here, Timema photo from Bart Zijlstra).

I have now moved to take up a lectureship in the School of Natural Sciences at Bangor University where I will work on the genetics of reproductive strategies in Timema and other critters.