The core dogma of conservation biology is clear: small populations are bad for species’ persistence. If we observe a population of endangered vertebrates harboring abundant deleterious mutations but without any reduction in fitness, what is happening there? I would like to bring up the curious case of the Channel Island foxes that was posted in the Molecular Ecologist blog a while ago and an interesting debate about using a small population as a source for genetic rescue that have been happening up until now.
First held in 1968 as a working group to discuss population genetics, the PopGroup conference is a yearly staple of UK-based evolutionary researchers (and increasingly researchers from further afield). However, this year there was to be no university student accommodation, no frigid lecture hall air-conditioning drama, and certainly no ceilidh dancing (although certain people – no comment – were perhaps not quite as devastated about this part), as the 54th ‘Liverpool’ edition of PopGroup was held online.
Although PopGroup is a small conference and lasts only 2.5 days it packs a punch – but a friendly punch, maybe something more akin to a fist bump. The meeting typically has an attendance of around 150-200, but for this year’s edition this number grew to around 400, with four parallel zoom sessions in contrast to the usual two or three. In addition to the the increased attendance was a notable, and welcome, increase in geographic breadth of attendees, from a typically UK-centric attendance (also reinforced by the fact that PopGroup is always held around the Christmas/New Year period), to this year’s edition, which included speakers based in over twenty different countries. This year’s plenary talks spanned a variety of topics including the spatial patterns of genetic variation, longevity and anticancer mechanisms in mammals, the evolutionary ecology of host-defence, and the impact of drosophila seminal proteins on fertilisation and fitness (a list of plenary speakers can be seen HERE).
The following is a guest post by Ornob Alam, a graduate student in Michael Purugganan’s lab at New York University. Ornob’s PhD projects examine the demographic and evolutionary history of domesticated Asian rice in the context of past climate change and human migrations.
In 1859, the English naturalist Henry Walter Bates emerged from the rainforests of Brazil after more than a decade of recording the natural history of the region. Among his many discoveries, the adaptive strategy of mimicry in butterflies has in particular become embedded as a key area of study in evolutionary biology.
Bates noted that some butterflies that were different enough to be classified as separate species (or subspecies) closely resembled each other in wing color patterns. He concluded that certain butterflies had evolved to mimic others that were poisonous and avoided by birds. Birds learn to interpret the wing color patterns of poisonous butterflies as warning signals to avoid eating them, and any non-poisonous species that resembles a poisonous one gains some protection from predation.
Bates, however, was not able to explain why different poisonous species living in proximity also sometimes resembled each other. In 1879 Fritz Müller, a German naturalist, finally explained this as a numbers game. Teaching birds to recognize warning patterns comes at a cost, in the form of a certain number of individuals being eaten. When two poisonous species evolve to share the same wing color pattern, they share this cost and reduce it for each individual species. If a bird learns to avoid one species, the other benefits, and vice versa.
All of that helps to explain the selection pressures that favor the evolution of these two types of mimicry. But how does one species come to resemble another? Does the mimicking species independently evolve genetic variants that produce similar wing color patterns to the mimicked species, or is there occasional interspecies mating and flow of genetic variants between different species? If they do independently evolve the same patterns, do the genetic variants underlying the patterns in the different species occur in the same regions of the genome?
There are multiple answers to these questions, depending on the colors, patterns, or species being considered. Let us attempt to answer them in the specific context of Müllerian mimicry, where different poisonous species share similar wing color patterns, in Heliconius butterflies. We will look at two (relatively) recent studies that come away with interesting but seemingly contrasting conclusions.
With the new year, we’re bringing on some new contributors to the blog, as promised. Please give a warm Molecular Ecologist welcome to Sabrinha Gita Aninta and Rishi De-Kayne, introducing themselves below. Keep an eye out for their first posts soon!
About six months after The Molecular Ecologist‘s tenth anniversary, we’ve hit another round-number milestone — this post is the one thousandth published on the site. I’ll refer you to that anniversary post for a rundown of highlights from the nine hundred and ninety nine that precede it. For this one, I thought I’d turn the focus outward — to our readers, and to what we’ve got to offer in the new year.
Yikes. This year has been a doozy, and while we all know that the hand on the wall (if you have one of those old fashioned things) that strikes midnight on December 31st will not put out the dumpster fires that we are living amongst, we can hope that 2021 will (maybe….possibly) bring something good… yes, I’m knocking on wood.
I know I’m not alone, but I’ve recently heard a bunch about viruses. Maybe it’s fitting to end this chapter of what has turned out to be a completely wild year, by learning even more about viruses…of the giant variety.
A new episode of The Molecular Ecologist Podcast is now out on Anchor.fm. In this episode, Stacy Krueger-Hadfield, R Shawn Abrahams, and Jeremy Yoder chat about their experiences managing research, teaching, and scientific conferences in the year of COVID-19.
(This episode was recorded back in October, but production’s been delayed because of, well, everything. It’s still a pretty good retrospective on a strange and challenging year!)
It was the Ides of March in 2020 when I moved from California to Europe. Thanksgiving marks March 271st. I was still a postdoc in Jonathan Eisen’s lab at UC Davis and my contract would have ended in the end of August 2020. In March 2020, my husband and I were in the process of booking a container to bring our belongings through the Panamá Canal to Europe. He was applying for jobs in Germany, I had already an offer, and we were looking at schools for our children. I was in the middle of analyzing my data I had collected during one of the many field trips to Central America in the months before, when my mom from Switzerland called and told us we have to come now. Switzerland is closing its borders in the next few days and many European countries are already closed!
Graphical abstract for Thanksgiving methods. Idea by Grace Ho @Gracegusta. Sorry Canadians, that this idea comes a bit too late!Continue reading →
Records for sequenced mollusk samples along the southern California coast (GEOME)
Infrastructure to make genetic data widely available for research beyond its initial publication has been a theme of the genomics revolution, from GenBank to the Sequence Read Archive. For molecular ecologists, though, genetic data is only half of our field — the other half is the ecological context in which that data is collected. This month, Molecular Ecology Resourceshighlights an initiative to bring that ecological context to genetic data archiving: the Genomic Observatories Metadatabase, or GEOME.
Led by Cynthia Riginos at the University of Queensland, Eric Crandall at Penn State, Libby Liggins at Massey University, and Michelle Gaither at the University of Central Florida, the GEOME collaborators present the case for creating yet another data deposition service: although there are a number of established databases for public deposition of genetic and ecological data, no one repository linked both types together. GEOME, which launched in 2017, offers a single metadata framework to link DNA sequence or marker data to sample locality and ecological measurements.
GEOME allows researchers to create records linked to sequence data they’ve already posted to a public repository — or, now, to upload samples to the International Nucleotide Sequence Data Collaboration SRA alongside ecological data through a single unified portal. Datasets are then searchable through the GEOME website, which includes multiple levels of search control alongside a useful map visualization, or through a new R package that interacts with the GEOME API.
Life as we knew it came to a screeching halt back in March. Almost a year ago, how is that possible??? Yet, at the same time it feels like several lifetimes have passed …
At a recent editorial meeting, we were talking about TME posts and in the past, I’ve written about fieldwork. I always felt fortunate to be able to travel to far flung places, but I don’t think I truly appreciated how much being out in the field really meant to me. In between bouts of existential dread and complete overwhelmed-ness over the last 9-odd months, I’ve realized how much I took for granted. Fieldwork was one thing that was simply part of the fabric of my life.
Our time in the field entails long days of driving hither and yon, sampling (often in hot, humid weather or the freezing rain – we like extremes I guess), and then processing late into the night. At some point Cher, Céline, or some other guilty pleasure musician make an appearance to get us through the slog – whether in the lab or on the road. Sometimes, we’re processing samples in a nice lab. Other times, we’re sitting backwards on a toilet in a Motel6 using the tank lid as a makeshift bench. We eat too much McDonald’s, go back for more and regret it immediately. Yet, these are the times of the year I find myself anxiously awaiting, counting down the days on my calendar until we are on the road.
