Searching for heroic MHC genes in the fight against fungal takeover

Frogs have been disappearing all around the world in the past few decades. The reasons for these declines have been complex, but one of the biggest players is a nasty disease with an even nastier-sounding name: chytridiomycosis.

I don’t know much about fungus, but I’m pretty sure this is typical chytrid morphology. Artwork via Ethan Kocak, author of The Black Mudpuppy


Batrachochytrium dendrobatidis (Bd) is the particular fungus responsible for chytrid in frogs, and while hundreds of amphibian populations (and species!) have already been lost to this pathogen, there are many other populations that are doing just fine*.
So chytrid is a big problem, but predicting susceptibility to chytrid in natural populations is tricky business. A major focus of this effort is understanding how immunity is conferred to amphibians populations, and this process starts with the heroic genes that are most responsible for fighting chytrid: those of the major histocompatibility complex (MHC).
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Posted in adaptation, association genetics, selection | Tagged , , | Leave a comment

hyRAD and museum genomics

While the RAPTURE may have arrived, the development of novel restriction digest-based library prepartation techniques — and portmanteaus — continues unabated. In a paper published in PLoS ONE last month (and previously available as a preprint on bioRxiv), Tomasz Suchan and colleagues describe the latest of these methods, introducing “hyRAD” to the molecular ecology lexicon.
hyRAD (from hybridization RAD sequencing) differs from its predecessors in employing fragments generated from a standard double-digest RAD protocol as biotinylated probes. These probes are then hybridized with fragments from shotgun genomic libraries, capturing homologous sequences for PCR enrichment. By sequencing both the original ddRAD library and the enriched shotgun library, short reads from the latter can be assembled into contigs and mapped onto the former. (Because its protocol differs significantly from other RADseq variants, hyRAD requires a unique bioinformatic pipeline, which is also presented in the paper.)

Figure 1 from Suchan et al. (2016), providing an overview of the hyRAD approach

Figure 1 from Suchan et al. (2016), providing an overview of the hyRAD approach


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Posted in genomics, methods, natural history, next generation sequencing, phylogenetics, phylogeography, population genetics | Tagged , , , , , | 3 Comments

A note about e-mail subscriptions

Screen Shot 2016-03-31 at 2.11.13 PM
If you recieve The Molecular Ecologist by e-mail, you’re far from alone — we have almost 650 subscribers recieving e-mailed posts via the Feedburner service. (How do you know if you’re one of them? You are if you’re reading this in your e-mail inbox, as a message sent by noreply+feedproxy@google.com.) Feedburner has been a pretty reliable service for this over the years, but it does some things that are a little less than ideal, mangling the formatting and leaving off critical information like the byline.
So a little while ago, we replaced the Feedburner e-mail signup in the sidebar with a signup form for e-mails delivered by a WordPress plugin. The plugin sends Molecular Ecologist posts as e-mail messages with formatting better preserved, and with author bylines right up front; people have started signing up for that service, and we’re ready to make the transition official. We’re going to discontinue the Feedburner e-mails, which means that if you’re one of the people receiving them, you need to sign up for the new system to keep getting TME by e-mail.
Signing up for the new e-mail system is as simple as navigating to www.molecularecologist.com and entering your e-mail address in the box in sidebar on the right — you should get a confirmation e-mail sent to that address immediately. Once you’ve confirmed your new subscription by clicking the link in that confirmation e-mail, you’re all set to recieve TME in the new, better format.

Posted in housekeeping, technical | Tagged | Leave a comment

How to Clone a Mammoth: When science fiction becomes reality

The Molecular Ecologist receives a small commission for purchases made on Bookshop.org via links from this post.

When I explain that I study the woolly mammoth, sooner or later (and usually right away) comes the question, “Are you going to clone a mammoth?” From childish excitement to real scientific interest, the idea of cloning a mammoth raises general enthusiasm.

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How to Clone a Mammoth: The Science of De-Extinction by Beth Shapiro.
Buy it on Bookshop.

Despite the fact that my research is not related to cloning a mammoth, I had to learn about the cloning efforts, so that I can answer the numerous questions.

Luckily, the book How to Clone a Mammoth: The Science of De-Extinction by Beth Shapiro was published last year. It’s essential reading for everybody interested in understanding the current state, future prospects, and all the challenges of cloning a mammoth.

Shapiro’s book was published at the same time as international headlines reported on the woolly mammoth genes being successfully inserted into elephant cells by Harvard geneticist George Church and his team. It was a media sensation similar to the one experienced in 2013 after the TEDxDeExtinction event and publication of Carl Zimmer’s National Geographic article, “Bringing Them Back to Life”.

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Posted in book review, Paleogenomics | Tagged , , , | 1 Comment

What makes a range?

Why do species have restricted geographic distributions?

Classic ecological perspectives tell us distribution limits occur where ecological parameters coincide with the boundaries of ecological niches. Evolutionary perspectives, on the other hand, surmise distribution boundaries reflect a failure of niche evolution. Though small population size and limited genetic variation in ecologically relevant traits likely limits a species’ distribution, few studies have investigated multivariate phenotypes.

© wikipedia

© wikipedia


 
Paccard et al. (2016) did just that in The American Naturalist. They investigated whether populations at latitudinal limits had different quantitative genetic architecture of ecologically relevant traits compared to those populations found in the middle of the range.
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Posted in adaptation, evolution, plants, selection, theory | Tagged , , , , , | Leave a comment

The dangers of not thinking about the relics

saint-erik-skull-crown

No, I’m not talking about Saint Erik’s skull from his beheading in 1160, which (as it turns out) might just be real. A hot topic in microbiology is a different kind of relic.

Amazing developments in microbial ecology in recent years have really opened up a new window to understanding the diversity of microbial communities and uncultivated organisms that are hanging out around us. As we continue to develop more affordable sequencing methods (and if you happen to sequence things, please take a few minutes to fill out a survey we posted earlier), the availability of sequence data has absolutely exploded.
Microbes play an important role in the environment, and linking specific lineages to what is actually happening involves figuring out who is metabolically active. Some studies previously been assumed that metagenomic data sets represent DNA from the living cells that drive biogeochemical processes, however, this is not the case.
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Posted in bioinformatics, community ecology, metagenomics | Tagged , , | 1 Comment

Thanks!

(NBC Universal)

(NBC Universal)


Our crowdfunding campaign wrapped up last night at midnight, with a total of $1240 pledged by 24 supporters — enough to support the basic costs of the blog, and to tackle some of our more ambitious plans for the future, too. On behalf of all the Molecular Ecologist contributors, I’d like to thank everyone who pledged and helped spread the word about the campaign.
What’s next? Well, Indiegogo will release the funds within a couple weeks — as soon as they do that, our first order of business will be to send out the thank-you gifts our contributors have earned, and to pay off our hosting bills for 2016. I’ll e-mail contributors for information like tee-shirt sizing and shipping addresses, as needed.
We’ll also be putting together an audience survey to help determine how we can best spend the remaining funds, and to identify the best approaches for supporting the site in 2017 and beyond. Keep an eye out for that!
How to fund science communication, like issues of funding newsmedia in general, has been a perpetual question since before I got into science blogging, and it’s a tricky one to navigate. Here at TME, we write about the science we know and love, and precisely because we think that what we write about is important, we want to make it available to anyone with a web browser. Still, I do believe that valuable work shouldn’t be done for free, and I hope that what TME provides to our fellow molecular ecologists, and to the general public, is valuable. I think this experiment in fundraising has given us the first part of an answer to that conundrum, and I’m grateful to everyone who helped us find that answer.
— Jeremy

Posted in community, funding, housekeeping | 1 Comment

The Molecular Ecologist's Survey on High-Throughput Sequencing

Last week we updated the Field Guide to Next Generation DNA Sequencers to better reflect the sequencing techniques of 2016. The NGS Field Guide is one of the most popular resources on the Molecular Ecologist web site, but we don’t know much about how our readers use the various new sequencing techniques.
In order to gauge the usage and interest in high-throughput (next-gen) sequencing, we ask you to kindly fill in this short, anonymous survey. Results will be compiled and posted shortly after!

Posted in bioinformatics, genomics, methods, next generation sequencing | Tagged , , , , | 2 Comments

Using R to mine species data

Many of us generate more data than we know what to do with (speaking of which: keep an eye out for the 2016 NGS Field Guide, coming soon!), so it’s easy to forget about the piles of data already at our fingertips. Research potential is hidden in online resources like GBIF, iDigBio, VertNet, and the IUCN database, and some great R packages make it possible to batch download enormous amounts of data at once.
Here’s an introduction to a few R packages that make it easy to mine data on species occurrences, conservation statuses, and more.

Species conservation data

Species conservation information is easy to retrieve using two R packages, available through ropenscilabs: rredlist and taxize. As an example:

library(devtools) #used to download packages from github
devtools::install_github('ropenscilabs/rredlist')
devtools::install_github('ropensci/taxize')
library(taxize)
library(rredlist)
iucn_summary('Gulo gulo')

The output from “iucn_summary(‘Gulo gulo’)” tells us that:

1) The status of Gulo gulo is “Least Concern”

2) Gulo gulo was reassessed as “Near Threatened” in 2008

3) Gulo gulo is found in 9 countries: Canada, China, Estonia, Finland, Mongolia, Norway, Russia, Sweden, and the United States

4) Gulo gulo‘s population trend is decreasing

Also note that the package taxize has several additional tools for taxonomists, such as species name verification and taxonomic hierarchy information.

Species occurrence data

Retrieving and visualizing species occurrence data is easy with the R packages dismo and maptools:

install.packages(c('dismo','maptools'))
library(dismo)
library(maptools)
Soug<-gbif("Sorex", "ugyunak", geo=T, removeZeros=T, args=c('originisocountrycode=US', 'originisocountrycode=CA')) #retrieve all occurrences of Sorex ugyunak from the U.S. and Canada
Soug_xy<-subset(Soug, lat !=0 & lon !=0) #retain only the georeferenced records. This can also be done by including geo=T in the previous command
coordinates(Soug_xy) = c("lon", "lat") #Set coordinates to a Spatial data frame
data(wrld_simpl)
plot(wrld_simpl, axes=TRUE, col='light green', las=1) #plot points on a world map
zoom(wrld_simpl, axes=TRUE, las=1, col='light green') #zoom to a specific region
points(Soug_xy, col='orange', pch=20, cex=0.75)

Which gives the following result:

Simple occurrence map for Sorex ugyunak

Simple occurrence map for Sorex ugyunak

Collection data

Other helpful R packages include ridigbio, rvertnet, and rgbif, which allow you to download data from (you guessed it!) iDigBio, VertNet, and GBIF. These are particularly useful for obtaining museum collection information, including record counts by year or by institution.
What’s your favorite tool for data mining in R? Let us know in the comments below.

Posted in howto | Tagged , , , , , | 12 Comments

The Fourth Reviewer: Help! A reviewer just contacted me directly.

It's worth your time to open up your Rolodex (TM) and recommend some reviewers — but give the choice some real thought. (Flickr: Ged Carroll)
It’s worth your time to open up your Rolodex (TM) and recommend some reviewers — but give the choice some real thought. (Flickr: Ged Carroll)

Tim Vines is an evolutionary ecologist who found his calling in the process of peer review. He was Managing Editor of Molecular Ecology from 2008 to 2015, he launched The Molecular Ecologist in 2010, and he’s the founder and Managing Editor of Axios Review. Now, Tim is also The Fourth Reviewer, taking on your questions about peer review and publishing. Got a question for the Fourth Reviewer? Send us an e-mail!

I’m just working through submitting a manuscript for review, and I’ve come to the page where the editorial system asks me to suggest some possible reviewers, and name any who would be inappropriate. Apart from collaborators and others with conflicts of interest, I don’t know of anyone in my field who shouldn’t review this paper. But I’m always a bit nonplussed by the request for suggested reviewers — it’s easy for me to pull up some appropriate names, but I feel like even making the suggestion taints their opinions with the perception that I think they’ll give a favourable review. Do editors actually use reviewer suggestions from authors? — Conflicted Contacts List

This is an endless source of discussion and dispute, both outside journals and within them. Some journals really like to use suggested reviewers, and even require that authors provide them at submission. Other journals won’t touch them with a bargepole.

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Posted in community, peer review, science publishing, The Fourth Reviewer | 2 Comments