Ants, Bees, Genomes & Evolution

@ Queen Mary University London

Posted to bioRxiv: Degenerative Expansion of a Young Supergene

May 23, 2018

We have just posted a new manuscript to bioRxiv, where we describe the structural differences between the SB and Sb versions of the fire ant social chromosome pair.

We find that Sb is larger than SB and discuss how the suppression of recombination of Sb would lead to this type of ‘degenerative expansion’, as hypothesised for Y chromosomes and other non-recombining chromosomal regions. Read the manuscript, and tell us what you think!

The Wurmlab at the Tower Hamlets Festival of Communities

May 18, 2018

Fantastic Minibeasts and where to find them

This year the Wurm Lab were out in force at the annual Festival of Communities held in Stepney Green Park on Saturday 12 May. We brought some of our lab colonies of social invertebrates to demonstrate differences in social complexity including: Messor barbarus ants, Bombus terrestris bumblebees, and Stegodyphus dumicola social spiders. We had a fantastic time talking to the public about our research, taking groups around the park on minibeast safaris, and running a kids’ craft table where solitary bee hotels made from recycled drinks cartons were beautifully decorated. It was an immensely enjoyable day meeting people from the local community and some very enthusiastic and inspiring future scientists.

Keeping up with reading newly published articles

February 20, 2018

What is it? We called it the Index, it is our monthly reading review, tailored to our areas of interest and research.

Why do you do it? Because there are so many articles being published it can be quite difficult to keep up with reading new material. We want to increase our general knowledge of important questions, techniques and discoveries in our wider research areas while decreasing the likelihood of missing any relevant “key papers”. We are also keen to efficiently help each other out by sharing our readings. Finally, we are getting to read more broadly - including topics outside our comfort zone.

How does it work? Each month, each Wurmlab member gets a list of three journals to review from our own journal generator. The script is on Github here. Three articles that are relevant to the group or a particular lab member are picked form each journal’s table of contents. These articles are added to a document that anyone in the lab group can read at any time.

Great, where can I see an example? See the last instalment of the Index here.

Brazil! IUSSI symposium on the evolution of social organization

February 15, 2018

Join us in Guarujá!

We (Emeline, Carlos & Yannick) are excited to host a symposium on the evolution of social organisation at the upcoming IUSSI conference.

We welcome a diversity of approaches and study systems. If you’re unsure about the relevance of your work, don’t hesitate to get in touch.

Full symposium title and abstract below:

Evolution of social organization

How an insect society is organized varies tremendously between but also within species and populations. Such diversity includes variation in numbers of reproductive individuals, modes of reproduction and of dispersal, relationships with neighboring colonies, degrees of morphological and behavioral caste specialization, and interactions (mutualistic, parasitic, predatory…) with closely or distantly related species.

Understanding how and when changes in social lifestyle occur is central to the study of social evolution. More specifically, can we measure the evolutionary pressures involved in changes of social organisation? Are particular ecological conditions involved? Can molecular, genetic or physiological features constrain or facilitate social evolution? What are the effects of a change in social interactions on how natural selection can act?

Encompassing the complexities of such multifaceted topics requires interdisciplinary discussion. This symposium will thus include both theoretical and empirical research addressing the topic from a variety of scales and angles.

Easy mistake comparing numbers in R

January 3, 2018

It shouldn’t really be necessary to share this. But it keeps popping up (in particular when students are learning to program in R).

It is nonsensical to compare text to numbers. But R will let you. For example:

> "a" > 1
[1] TRUE
> "A" > 1
[1] TRUE
> "bob" > 99
[1] TRUE

I suspect that this is a remnant of the desire to be able to compare letters (e.g., for sorting ASCII characters alphabetically “A” < “D”).

Problem comparing numbers and “text as numbers” in R

When new to programming in R, you might ask the user to input a number. For example with

input_number <- readline(prompt="Enter a number: ")

This comes into R as text, not as a number. Unless you run as.numeric() or strtoi() on the input, it will remain text. Comparisons are then equivalent to the following

> 1 == "10"
[1] FALSE
> 10 == "10"
[1] TRUE
> 100 == "10"
[1] FALSE
> 11 < "10"
[1] FALSE
> 1 < "10"
[1] TRUE
> 9 < "10"   # <- uh-oh
[1] FALSE
> 3 < "10"
[1] FALSE

Note that some of these comparisons yield the result that you would expect if only comparing numbers. But some of them (e.g., the last 2) give you an incorrect response. This is dangerous.

R does not show an error message; it acts as is everything is ok, and gives you a response that looks reasonable (i.e., TRUE or FALSE). It would thus be easy for this type of mistake to go undetected.

How can this type of number comparison problem in R be prevented or detected?

  • Always check/force the type. If you run as.numeric() or strtoi on something text that is not unambiguously a number, R will show an error message or return NA.
  • Use a testing framework such as testtthat to ensure that even the small pieces of code you write behave as you would expect.

Brief end of year update - publications and presentations

December 27, 2017

Despite the lack of updates, things have been happening!

Analyzing the genomes of all the ants

After our discovery of extremely low genetic diversity in the Sb variant of the fire ant social chromosome, we asked what is going on with Gp-9? This is the original odorant binding protein that Ken Ross found - using starch gel electrophoresis - to be fully associated with single vs multiple-queen colonies.

The patterns described back then still hold, but surprisingly we find that nine additional Gp-9-like odorant binding protein genes are in the social chromosome region of suppressed recombination. The descriptions of all 23 fire ant Odorant Binding Proteins, their expression profiles, and the differences between social chromosome alleles are detailed in Evolution Letters:

In a different paper, we review findings from the most recent analyses of the 23 ant genomes and 38 ant transcriptomes.

Conference presentations

Lab members had the opportunity to present at many occassions, including:

  • Roddy Pracana presenting at the London Epigenetics Club meeting on Gene-Environment interactions in non-traditional model organisms.
  • Recently finished MSc student Gino Brignoli presenting his Lasius flavus at the Northwest europe IUSSI meeting in York
  • Current BBSRC Lido rotation student Isabel Fletcher showing the impact of pesticide on gene expression in bumblebees at the Northwest europe IUSSI meeting in York
  • Yannick’s giving a Keynote at the annual meeting of the french section of society for the study of social insects, as well as presenting at ENS Lyon, the London Next Generation Sequencing Congress and the joint Genome 10k and Genome Sciences conference in Norwich. The latter was elegantly Illustrated by Sanger’s Alex Cagan:

Degrees degrees degrees

Finally, we congratulate Gino Brignoli & Abdoulie Kanteh for the high marks achieved for their MSc disserations, and Roddy Pracana for submitting his PhD:

Performance and user centric updates to Afra's annotation editor

August 29, 2017

Written by Hiten Chowdhary, cross-posted from (http://www.hiten.io/blog/articles/gsoc-17/)[http://www.hiten.io/blog/articles/gsoc-17/]

This is a summary of the work done during this summer as part of Google Summer of Code 2017 under the organisation Open Genome Informatics under the guidance of my mentors Yannick Wurm and Anurag Priyam.

About the project

Problem Statement: Performance and user centric improvements to Afra’s annotation editor.

Brief explanation: Gene prediction models are visually inspected and manually corrected for any mistakes. Curation of gene models is carried out on Afra, a crowdsourcing platform. Afra has two models - an annotation editor and a task processor. The annotation editor is build using JBrowse and WebApollo. This project focuses on migrating Afra to the latest JBrowse and getting a unit test suite ready to optimize the annotation editor and ease the learning curve of manual curation.

Project Summary

Before the project started, I was fairly acquainted with javascript and ruby. Initially, I got familiar with JBrowse’s codebase and understood the upgrades along with changes made in different versions. We planned to get the test suite ready before the migration of Afra takes place. With the test suite in place, the migration would take place without any hassle. One can run tests to ensure annotation editing functionality is working properly.

For migration of Afra, we took a look at JBrowse and Afra’s codebase. We examined the files added to Afra’s codebase, which exhibited the annotation editor functionality along with additional features of Afra. These differences in codebase were carried over to JBrowse as a plugin. This provided the annotation editor functionality which could be easily plugged into JBrowse or any other Genome browser.

Test Suite

Annotation editor uses Jasmine for unit tests. Jasmine was easy to setup and can be executed using a simple web server. I examined the already implemented tests for different functionalities of Afra. This provided me an insight into the processing of tests implemented in Afra. Further, I added some tests for the annotation editor functionality. These tests were:

  • Flip strand : Checks whether the annotation editor is correctly changing the genome’s strand.
  • Set longest ORF: Checks whether annotation editor adequately implements the longest open reading frame for a given transcript.
  • Mark non canonical splice sites: Checks whether the annotation editor is duly marking the non canonical splice sites for the transcript.
  • Mark non canonical translation start site: Checks whether the annotation editor is duly marking the non canonical start translation sites for the transcript.
  • Mark non canonical translation stop site: Checks whether the annotation editor is duly marking the non canonical splice sites for the transcript.
  • Filter features: Checks whether the annotation editor is properly filtering a given type of transcript (say exons) from a given set of transcripts.
  • Copy feature: Checks whether annotation editor is making an exact copy of features passed to it.
  • Merge exon: Checks whether annotation editor suitably merges two given exons and returns a new transcript.
  • Create transcript: Checks whether annotation editor creates a new transcript using Simple feature, for the provided features.
  • Resize exon: Checks whether annotation editor adequetely resizes the exons.
  • Get CDNA coordinates: Checks whether the annotation editor provides correct cdna coordinates for a given transcript.
  • Delete exon: Checks whether annotation editor properly deletes a exon from a given transcript.

Here is the link to my commits for the test suite.

Migrating Afra to latest JBrowse

We started building a plugin for the JBrowse to carry over the annotation editor functionality to JBrowse. This would provide Afra’s annotation edition functionality to use the latest JBrowse features, making the migration process smoother. The plugin development took place in the following steps :-

  • Edit track implementations : First task was adding a new track to JBrowse’s browser for plugin’s initialization.
  • Adding drag and drop feature : Next task was including proper jquery scripts and modifying the properties of existing tracks, so that they can be dragged along the y axis and dropped to edit track for annotating them.
  • Edit track drop capabilities : Subsequently, we initialized the edit track and made it capable to accept the incoming features and make them available for annotation editor for further modifications.
  • Accessing annotation editor’s functionality : Now that we could successfully dragged and dropped a feature in edit track, it was time to use the annotation editor functionality to make required changes to the track. This list of functionality is available upon right clicking the feature in edit track.
  • Getting right click menu items working: By this stage we had got a front end in place to access the annotation editors functions. Now it was time to get those functionality such as get sequence, send to Gene Validator, resize exon, etc ready.

Now we had a basic plugin in place that had implemented the basic annotation editing functionality. (commit)

Now additional features of Afra had to be carried over. These feature are :-

  • We implemented triple click on track to zoom to base pair level directly. (commit)
  • Following this, we replaced the JBrowse’s reference sequence track with Afra’s. Now, when the feature in edit track is selected, the corresponding track in reference sequence gets highlighted. (commit)
  • We added a feature to view the residues (actual genomic sequence ‘atgc’) of the feature in edit track when it is selected. (commit)
  • We implemented an additional feature to validate the feature dropped in the edit track. We checked for non canonical translation start and stop sites and marked them with orange exclamation marks. This will help the user easily look for non canonical splice sites without looking into the sequence of the feature. (commit)

Finally, we had successfully implemented the annotation editor of Afra as a plugin of JBrowse, along with extra features of Afra too. Further, to test whether all the annotation editing functionalities are working properly we implemented the test suite for the plugin.(commit)

Emeline and Natalia at Evolution meeting (Portland, Oregon)

July 10, 2017

The Evolution meeting took place this June in Portland, Oregon. This meeting is organised every year and is one of the largest conferences in our field.

Creating their schedule from an incredibly rich program of up to 13 parallel sessions, Natalia and Emeline caught up with the latest on social systems, genomics and evolutionary stories. They also participated in the conference:

  • Emeline presented the results of her first year of PhD on the genomics of the socially polymorphic ant species Pheidole pallidula
  • Natalia gave a talk on the DNA methylation on bees. This was the final presentation before her PhD viva. We are very happy to congratulate her on successfully defending her thesis - congratulations Dr Natalia Araujo!

The meeting was a wonderful occasion to catch up with collaborators and presenting the Wurmlab research to this (mainly) North American audience. Next year, Evolution will join ESEB in Montpellier (France), for a joint meeting.

Joe, Carlos and Priyam present at Insect Genomics meeting

May 16, 2017

The Royal Entomological Society’s Insect Genomics Interest Group meeting took place on May 16th at the Rothamsted Research Centre.

The speakers to this event included highly relevant researchers from all over the world, covering a wide range of subjects in insect genomics, from pest control to evolutionary biology. Of course the Wurmlab could not miss this chance and Carlos Martinez-Ruiz, Joe Colgan and Anurag Priyam attended the event to disseminate our research:

  • Joe gave a talk on the signatures of positive selection in the genomes of bumblebees (Bombus terrestris) from populations around the UK
  • Carlos presented the preliminary results of his PhD project on the signatures of evolutionary conflict in the transcriptome of the fire ant Solenopsis invicta
  • Priyam presented a poster explaining the benefits of using SequenceServer as a BLAST interface and using GeneValidator to determine quality of gene predictions.

The meeting was very fruitful, and offered exciting opportunities for collaborations between the Wurmlab and other researchers from institutions in the UK and abroad.

We look forward to the next meeting!

Paper on Social Chromosomes Accepted

February 21, 2017

Our paper on the genetic diversity of the fire ant social chromosomes has been accepted in Molecular Ecology and is now available online!

The fire ant social chromosomes carry a supergene that controls the number of queens in a colony. We describe a few features of this supergene system:

  • The two variants of the social chromosomes are differentiated from each other over the supergene region, but without any evidence of evolutionary strata.
  • There is a large number non-synonymous substitutions between the two variants.
  • The never recombining variant Sb is almost fixed in the North American population.

You can check out the press release, which covers some of the details about our work.

The full reference is: R Pracana, A Priyam, I Levantis, RA Nichols and Y Wurm. (2017) The fire ant social chromosome supergene variant Sb shows low diversity but high divergence from SB Molecular Ecology. DOI: 10.1111/mec.14054

All posts

Scientific writing (2015/02)
Reference Letters (2014/01)