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What is that Slime Animal?

1/24/2016

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Marine creatures look weird. We know what a fish looks like, and some people have seen a sea star, but some animals like the giant squid are 30 feet long and so elusive we have only caught them on video two or three times. Animals come in all different shapes, sizes and colors and each species has its own feeding behaviors and habitat they call home. Typically we categorize animals based on their morphology, if two creatures look similar they are probably related. But this doesn’t always work, if a creature has no features how can you determine who are its closest relatives?
 
We still don’t know very much about a lot of animals, for instance myxozoans are one creature in particular that has confused scientists for a long time. The name myxozoan is a combination of Greek words that mean slime animal! You have probably never heard of myxozoans because they are very small parasites that infect worms and fish in freshwater and marine habitats. These tiny parasites have confused scientists because there are very few morphological features to compare them to other types of life. A recent paper by Chang et al. uses advanced genetic techniques to show that myxozoans are a type of cnidarian, a phylum that includes jellyfish, anemones and corals.
 
So scientists found a creature that is slimy and related to jellyfish…who cares? Well probably the most exciting result of this paper is that these simple parasites have a very reduced genome, meaning they have lost many of the genes that are common to all animals between jellyfish and humans. A human genome consists of approximately 20,000 genes that are the basic blueprint for building a human. These genes are made up of strands of DNA that code for the material that runs every function in our body, and for the most part all animal genomes are made up of a very similar set of genes. Even though we look nothing like jellyfish we share 60% of the same genes with them.

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In the fish stage this parasite is called a myxospore.
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In the worm stage it is called an actinospore
There is a suite of genes that most animals share, and these serve basic functions that all animals need to survive. Think about how our body is laid out, we have limbs a trunk and a head, this body partitioning is created by a set of genes referred to as Hox genes. The genes Wnt program for cellular organization such as organs and the Sonic Hedgehog gene regulates the formation of limbs such as arms and legs as we develop from an embryo. These types of genes, the ones that are universally needed to make complex creatures are found in just about every animal. But what is exciting about myxozoans is that they have lost many of these ubiquitous genes. Humans have 20,000 coding genes and myxozoans only have 5,500. By reducing their size and complexity they can survive with a much smaller genome than even their most close relation, other cnidarians.
 
So we can start to ask some fundamental questions; what are the genes that are necessary for survival? The authors compared the gene functions to other cnidarians and found that the myxozoans had less genes for development, cell differentiation to make different tissues and cell to cell communication. This all makes sense, with less types of tissues to make and less cells in the body to communicate the myxozoans can survive even when these functions are removed from the genome. Basic genes that build complex body plans including HOX and Wnt and Hedgehog were all missing in the myxozoan genome.
 
This is really exciting; we are just beginning to understand what genes are absolutely necessary for complex life. Even more amazing is that we can sequence a genome at all! Twenty years ago it was impossible to look at the entire genome of an organism. In 2003 the first human genome took more than 10 years and 3 billion dollars to sequence. But now we can sequence a human genome for $1,000 and it takes about a week. Biology is going through a technological revolution, now we can sequence the genome of different organisms to really understand the building blocks of life even as we discover new wild and crazy creatures.

All photos from the website:
fishparasite.fs.a.u-tokyo.ac.jp

Original Article:
Chang, ES, Neuhof, M, Rubinstein, ND, Diamant A, Philippe, H, Huchon, D, Cartwright P (2015) Genomic insights into the evolutionary origin of Myxozoa within Cnidaria. Proceedings of the National Academy of Science, USA, 112:14912-14917.
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Biodiversity III: Extinction is Forever

10/27/2015

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Life has been on Earth for 3.5 billion years. But most of the familiar multicellular life related to modern plants and animals are 550 million years old. While we think there are currently close to 10 million species on our planet, over 5 billion species have existed but are now extinct. There are 99% more species that have died than are currently alive. When a species becomes extinct it is gone forever and no longer contributes to the maintenance of important ecosystem services including food webs. A mass extinction is when many species go extinct and entire ecosystems collapse.

So why do so many creatures go extinct? There is always a slow rate of extinction due to random events. The majority of species died during 5 mass extinction events that happened millions of years ago. The most recent event was 65 million years ago when dinosaurs were killed by an asteroid impact. This extinction probably killed 75% of the species that were on the planet. 200 million years ago an extinction event killed 50% of the living creatures and was caused by massive volcanic eruptions that produced toxic dust that blocked sunlight. The largest extinctions event on the planet was 252 million years ago and it caused more than 96% of marine and 70% of terrestrial species to go extinct. It is thought that high CO2 concentrations in the atmosphere caused widespread climate shift and increased ocean acidification enough to completely devastate food webs. The oldest known mass extinction event was 440 million years ago and also saw a huge reduction in species (60%, at that time there were no land species). This extinction event was caused by global cooling and a large-scale sea level drop. Common among all of these mass extinction events is that natural disasters caused a shift in the world’s climate. The species that exist on the planet are adapted to their current climate, species go extinct when climate changes.

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Currently the rates of extinction are much greater than normal. There is evidence that we are in the middle of the 6th mass extinction. Huge numbers of amphibian species are dying due to warmer temperatures and a fungal disease. More than half of Hawaiian birds have gone extinct due to habitat loss and a disease related to malaria. An entire group of 18 predatory bird species similar to a small ostrich went extinct in South America. The list goes on and on.

So many salmon have been caught and their rivers dammed up that many species are close to extinction. We created the Endangered Species Act (ESA) to protect species that are on the brink of extinction, but this legal mechanism does not fix habitat degradation, the root cause of extinction. For instance we built hundreds of dams in the Pacific Northwest during the 40’s for cheep electricity, to control flooding and for water security. We built way more dams than we needed and now these dams are blocking ancient spawning grounds of endangered salmon. Restoring essential habitat for these fish is critical to avoid their extinction. Many people don’t want to pay to remove dams, they say it is just not worth the money.  This type of short sighted outlook will continue our current rapid pace of extinctions, which could be slowed by the restoration of land and ocean habitats.

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But some people think that modern technology will save us from a mass extinction. You may have heard recent reports that we can use DNA to bring extinct animals back to life. Technically this is amazing, we can insert DNA in a cell and make it replicate itself to produce a living creature that has some of the genetic code of an ancient creature. This is basically cloning (remember dolly the sheep) but with DNA from a different species. Really a pretty major technical achievement, but fundamentally it does not help us, we need species that contribute to the larger complexity that makes the ecosystems we currently rely on for survival. We might be able to make a franken-creature that contains ancient DNA but we need healthy modern ecosystems, not to recreate ancient ecosystems.
 
So now we have caught ourselves in a pickle, we have created a changing climate that is causing mass extinctions! We are at a turning point in our history, if we wish to survive we must maintain ecosystem functions. We need clean air and water for survival, if we want to live on this planet we need the plants and animals that we have now. This life is what makes our planet habitable, makes it beautiful and richly complex. It would be a shame to cause a modern mass extinction that changes life as we know it. We need to actively protect the life on this planet to ensure that humans can continue to survive here.

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Biodiversity II: Why Save Diversity?

10/18/2015

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Scientists talk about how much life there is on the planet but why do we care? What is so important about having different species? If there are so many species what difference does it make if we let a few disappear?
 
Biodiversity is critical for life as we know it. Plants produce the oxygen we breath. Bacteria decompose waste. Coral reefs protect islands from eroding into the sea. Many different creatures have roles in keeping the planet clean and giving us important resources. When biology helps people to survive, we call this ecosystem services. These services come in many forms but they rely on the interactions among many different species. Think of these interactions as a chain, each link represents a species. As you break these links the chain breaks. When enough species are gone ecosystems stop functioning, stopping the services they provided for us. Imagine a planet without oxygen…not the easiest place to survive!

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 Clean water, air these types of services are critical for us but they are also critical for other organisms on the planet. We think of the inter relationships of different species as the threads of a spider web and each species are the connections. We often use this analogy to map out a food web. A food web shows which organisms each other organisms, typically with plants on the bottoms, herbivores above them and predators above the herbivores. As people we eat all of these levels of the food web, plants (like corn, broccoli, etc.), herbivores (cows, deer, etc.) and predators (tuna, etc.). As species go extinct connections on the web are broken and the organisms on higher levels no longer have as much to eat. If enough species from the bottom levels disappear then all of the upper levels collapse causing a cascade of species extinctions. Since we eat many of these organisms we should be actively working to preserve food webs to ensure we can feed people.

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Our health and survival is important, and medicines are one of the ways that we stay healthy. Most medicines come from natural sources, this makes sense, for thousands of years native cultures found plants and animals that had medicinal uses. Even now this is still true, approximately 60% of our medicines come from natural sources. We are constantly finding new chemicals from plants that cure a range of problems from headaches (aspirin comes from the bark of a willow tree) to cancer (taxol is currently the most used anticancer medicine and is derived from an evergreen tree). A cone snail like the one in the photo to the right contains a potent pain killer compound. But there are a huge amount of species that we don’t even know about (see the last blog). Many of these land and marine species might contain chemicals that are useful medicines but we have never tested this. We don’t even know the names of these creatures let alone how they might help us survive. This is a real problem, imagine if we let a species go extinct that had the cure to breast cancer. Once the species goes extinct there is no way for us to know what chemicals they contained. This is especially true for marine creatures, we have only been looking for medicines in marine animals for the last 40 years. This corresponds to our ability to scuba dive, before that we were really limited in our ability to find marine creatures. But we have always been able to walk around a forest and eat a plant (there must have been a lot of trial and error in the beginning). Currently there are 3 medicines made from marine animals, but you can imagine this is just the tip of the iceberg.

As our population increases more and more human actions are affecting the ability of different organisms to survive. We don’t often interact with most of the biodiversity that lives on the planet, but there is a huge amount of different creatures on the planet that all have a role to play in their habitats. It is critical that we appreciate diversity not only for its beautiful variety but also for the services that these creatures provide to us. Extinction is the biggest threat to these services because the species that die are gone forever. There have been 5 previous mass extinctions when life on the planet changed dramatically, for instance when the dinosaurs died. Some scientists think that we are in the middle of the 6th mass extinction. We have seen many species go extinct in the last 10,000 years, a relatively rapid rate for species to disappear. We should be very worried, all of the life on the planet helps us to survive so if we are causing a mass extinction we are breaking more links in the chain and disrupting food webs. We need to do everything in our power to stop extinctions and preserve biodiversity. We only live on one planet, and we need to actively preserve the rich biodiversity we have.
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Biodiversity I: How do you count life?

10/13/2015

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Biodiversity is a complicated thing, life comes in many shapes, sizes and forms. We are surrounded by an amazing diversity of plants, animals, fungus, bacteria and other weird microbes. Not only is the array of shapes and sizes dizzying, the variety of ways of getting food is crazy. For instance most consumers eat plants that produce energy from sunlight using photosynthesis. Some marine slugs actually steal chloroplasts from their plant food and harness photosynthesis for themselves. These little green slugs just need sunlight to eat. Imagine if we did this, green people that basked in the sun for food.
 
Biodiversity is amazing on many levels but we still don’t understand what we have on the planet. How many species are there? The truth is no one knows! Many scientists are interested in cataloging life and putting a name on species. This process is usually done by an expert called a taxonomist. Think of a taxonomist as a librarian, their job is to make sure the book is named appropriately and categorized based on its relationship with other books. A taxonomist names new species, which can be challenging since we want every species to have a unique name.
 
Since the beginning of naming (the idea that each species gets a unique two part name, a genus and species name was created by Carl Linnaeus in 1753) scientists have been adding more and more species to our library. We currently have named about 1.2 million species. This is pretty impressive, that is a lot of weird bugs. Literally almost a million of these species are insects, which is the most diverse group of animals. But that is just the tip of the iceberg, scientists are discovering many new species every day. Actually we are in the middle of describing all of the organisms on the planet and we probably haven’t even found 10% of them. This is a real problem, how can we hope to understand life if we don’t even know how many species are on the planet.
 
Most of the named species live in tropical rain forests, making this the most diverse habitat on the planet. The smallish country of Columbia hosts 10% of all the living species in a little more than 400,000 square miles. Coral reefs also hold a huge diversity of creatures, but no insects, so they come in second as the habitat with the most species. However, it is much more challenging to count the number of species underwater. To find creatures on reefs we need to scuba dive, but we are limited by the amount of air we can carry. This limits our time, most scuba tanks last me about an hour, and the most I usually do is four dives in a day, giving me 4-6 hours to look for creatures. This is not even close to the 16 hours (assuming the researchers sleep) that people can spend in a forest.
 
So what we need is a fast and easy method to quantify how many species are in an underwater habitat without actually being there. This is the topic of a recent paper “DNA barcoding and metabarcoding of standardized samples reveal patterns of marine benthic diversity”. In this paper marine biologist argue that using a standardized habitat is the best way to quantify the number of species in an area. They use autonomous reef monitoring structures (ARMS) as the habitat and these are built to resemble miniature apartment buildings. They have multiple plastic tiles stacked up to be about 10 tiles high, about 2-3 feet tall. If the ARMS are left underwater for 6 months or longer there are a ton of creatures that settle and grow on these plastic tiles. When the ARMS are brought out of the water and it can take a full day to sort all the weird creatures that they find. Then you have to count and put a name on everything you bring up, and preserve it so that the unknown creatures can be identified by taxonomists. Lots of work!!
 
Taxonomy is changing, now we can use genetics to identify a species, and compare the genetic code of two different individuals to confirm whether they are different species. This type of barcoding a species based on its genetics is how Leray and Knowlton counted the number of species they found in oyster reefs. Sequencing has recently changed enough to allow us to analyze hundreds of samples at the same time, which should revolutionize our ability to detect new species that were previously ignored.  This is really exciting, and allowed these scientists to determine that 8% of the species they found matched known species. ONLY 8%!! That means that more than 90% of the species they found have no genetic information in our databases. Some of these creatures could be new to science, or they might already have a name but we just don’t have any genetic data for them. We really don’t understand most of the life on our planet!
 
The great thing about ARMS is it is a standard method. So we have a standard way of comparing biodiversity across space and time…very cool. The disadvantage of ARMS is it is a standard method, it only represents one type of habitat. For instance these structures only attract species that like to live on plastic tiles. Other creatures that only live in coral will not be found in the ARMS. There is no way for ARMS to capture all of the creatures in an ecosystem. So we still can’t really answer the fundamental question of; how many species are there?
 
To discover biodiversity we can not replace putting people in the ocean and having them search for life. We also need more taxonomists, because without more experts there is no way for us to name and catalog all of the new species. Using genetic technology we are getting a much better idea of the biodiversity on our planet. Taxonomists continue to name and categorize life, and new technology is giving us a leg up on understanding how many creatures we have. At the same time our ability to catalog life is becoming more pressing as many species are disappearing even before we know what they eat or how they might help people.
 
Reference:
Leray, M. and Knowlton, N. (2015). DNA barcoding and metabarcoding of standardized samples reveal patterns of marine benthic diversity. Proceedings of the National Academy of Science, USA. 112: 2076-2081.



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Corals are Stressed Out! (Conservation Biology)

1/17/2015

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Do you feel stressed? Of course you have experienced stress, everybody has some sort of stress and stress happens to all types of plants and animals. Now this isn’t your bills adding up, broken car kind of stress…this is the world around us is changing and organisms are challenged to survive. As global climate change continues to grow unchecked the atmosphere, land and oceans continue to change in the physical conditions that animals are exposed to. For example lower elevations on a mountain are getting warmer, for some bird species that just means flying up a mountain, but trees can only move as seeds, taking generations to reach higher elevations. Even though a coral is an animal it very similar to a plant since it is cemented to the bottom of the ocean. This means that it can’t get up and move away when the going gets tough. Corals have to change their basic biology to survive changing conditions, and this is a natural process called adaptation. Adaptation has been going on for millions of years; however, climate is causing more rapid change and the pace of the increase in temperatures is unprecedented. Increasing temperatures directly threaten all the plants and animals that live in the oceans but corals are especially susceptible to temperature stress.

Corals are animals that live in tropical oceans around the planet. The tropical oceans don’t have a lot of food floating in the water so for 100’s of millions of years corals have learned to work with plants (some marine plants are called algae. You can see these algae as little brown spots in the coral polyp photo to the left) and bacteria to better survive in tropical waters. This collaboration called a symbiosis works because the coral provides a home for the algae and the algae pay rent in the form of sugar. This is easy for the algae, it captures sunlight and converts solar energy into sugar (the same photosynthesis that goes on in terrestrial plants). The sugar is a critical source of carbon for the coral and provides a large percentage of corals energy. Food for shelter has been a successful partnership for millions of years. 



But…of course there is a but. The algae can’t function in high seawater temperatures. The process of photosynthesis breaks down and they can no longer create the sugar they need to pay rent. In fact high temperatures cause so much stress to the algae they produce oxygen radicals. These toxins are bad, they are bad for people, zebras, and even corals.  These oxygen radicals damage cells, proteins, fats, all the basic building blocks of living creatures. Needless to say they are the source of much of the world’s stress! There are many ways to combat these toxins, a current diet fad for humans is to eat antioxidants…those are the chemicals that break down these toxins.

Unfortunately blueberries can’t protect corals from stress. In some cases corals produce enzymes that help to detoxify oxygen radicles. But often this isn’t enough and the symbiosis collapses. The algae leave the corals just as you would evict a tenant that doesn’t pay rent. This turns the coral from its normal yellow-brown color to a bright white (you can see this in the photos on the right, some coral colonies are still brown and some have bleached and are pale white). This is called coral bleaching because the coral has changed color to a bright white, just like bleaching your cloths. Ok, but if there are no algae then what do the corals get to eat? Very little…thus the big deal. Coral bleaching is a big deal, it is the break down of a critical symbiosis in a creature that builds habitat and reefs all over the world. This breakdown does not kill the coral immediately, but the corals do go hungry. If bleaching lasts for a few days to a few weeks, most corals can survive and regain their algae. But if high seawater temperatures persist for a long time corals will die. Talk about stress!


So bleaching is bad and corals are threatened by high seawater temperatures. Of course it is complicated…it's biology. Some species of corals bleach some don’t. Some corals live in really high seawater temperatures (like those found in the Red Sea) and don’t bleach. Some corals bleach every year even with little change in seawater temperatures. Some times every coral on a reef bleaches and other times two individuals of the same species that are right next to each other are bleached and unbleached (illustrated in the photos on the right). These are the kinds of questions that scientists are currently pursuing. We still don’t really understand why bleaching happens to some corals but not others and what we can do about it.


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So… why do you care? Some underwater creatures are stressed out and dying but you still have to drive to work and deal with bills and get your car fixed. Corals are critical creatures, just like trees they build habitat. They provide homes for thousands of other creatures including fish, crabs and shrimp. Corals build reefs that protect islands from storms. When the corals are dead the reefs erode away and no longer protect the shoreline, causing the loss of beaches and increased flooding of neighborhoods. Corals also provide important tourist revenue. This is a critical source of income for many people in developing countries. The great thing about tourists is they spend a lot of money but they don’t take anything home except photographs (hopefully). When the corals die, this source of revenue is gone and poverty increases, there is no seafood to eat, houses get destroyed by storms and a horrible cycle of poverty and destruction is created that causes the global economy to suffer.

Well coral bleaching is a threat and it is important for everybody to be aware of, but what can we do, this is a big problem. Well for one you can act locally. Recent research is showing that healthy corals are more resistant to higher seawater temperatures. This boils down to good local conditions ensure persistence of corals during extreme temperature events. Local habitat quality is an important issue for corals because they live in shallow waters next to tropical islands. This is right next to where all the people live. So how people take care of the land directly impacts the water quality of near shore habitats like coral reefs. If we cut down trees we create sediment run-off that goes into streams and is delivered right on top of corals often smothering them. If we dump oil down drains, this flows into near shore habitats contaminating corals. If we overfish a reef we change the dynamics of the ecosystem shifting the habitat away from corals towards fast growing algae. This means less space for corals and competition for the little bit of clear space that still exists. What we need to learn is even though we don’t see all the underwater creatures every day, they are directly impacted by the daily choices that we make. Our choices influence the amount of “stress” we create for many different organisms.

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Scaly Feet Give Lizards a Leg Up (Evolution)

11/23/2014

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What do lizards know, I mean really how could they teach us anything? A recent paper about lizards in Florida is a great illustration of evolution in action. The paper “Rapid evolution of a native species following invasion by a congener” written by Stuart et al., was recently published in the journal Science. This work is not only a great example of science done well but it highlights how fast selection can modify an organism’s body to survive a changing landscape.

A few quick definitions, I find that people don’t understand evolution because they don’t know the nuances of the definition. First evolution is change over time. No direction, no getting better, no superiority complex, just change. This is important because random mutations occur in populations and even if they aren’t beneficial they are still considered evolution (we call these random mutations genetic drift). Natural selection is a pressure that drives evolution in a direction (this is the heart of what Darwin and Wallace described in their research). When a habitat changes (gets dryer for example) an organism has to change (evolve) to survive the drought (a plant might have leaves with less evaporation). Any individual in the population that already has a random mutation that has less evaporation will be selected for, making that individual more successful and better able to pass its genes on to the next generation. So now you know that change (evolution) can happen by a pressure (natural selection) that makes an organism better able to survive and reproduce (the real currency in biology is reproduction because this is how genes persist) in a changing landscape.

Ok the lizards research, what did they discover? This study creatively used an occurring invasion by a novel lizard (Anolis sagrei) on a set of small spoil islands in Florida to test the impacts on a native lizard (Anolis carolinensis). These two species of Anolis eat the same thing, this creates a novel competition that the native lizards were never previously exposed to, a new selective pressure. This forced the native lizards to perch higher in the tree canopies. However, the features of these trees change as you go higher in the canopy, the branches are thinner and the bark is smoother. This makes it hard for the native lizards to hold on. The researchers found that over 10 years the native lizards changed their feet, they had larger toe pads and more lamellae (little scales on their feet that allow them to cling onto smooth surfaces better). This is incredible, in only 10 years these lizards evolved to take advantage of unoccupied space.

Ok into the nuts and bolts. So there are a few important considerations to understand when talking about natural selection. First, the absolute time is not really important, selection happens over generations, it is effectively selection of the fittest over many generations (this is because selection happens on heritable traits). So the researchers estimate that it took approximately 20 generations for these lizards to evolve these adaptive feet. This would only be a few weeks for some bacteria, or 500 years for humans (human generation time is somewhere between 20 and 30 years so for this estimation I’ve used 25 years). While this study is an impressive illustration of how fast evolution can work, the results are so striking because these researchers chose an animal with relatively short generation times.

There are some questions that I have that directly contribute to the speed of change in this system, but they aren’t mentioned in the study. What is the variation in toe size and lamellae number in a natural population? This gets at the very essence of how selection works. Natural variation is the raw material of selection.  If there were a wide variety of toe sizes in the lizards before the introduction of the invader, there would be a lot of raw material for natural selection to act on. However, if there was very low frequency of larger toes in the native lizards, you could imagine that it would take longer for these traits to develop. Also what is the selective pressure of competition? This is a very difficult thing to measure, how “powerful” is competition in driving change over time. In many ways this study shows that competition is a strong selective pressure. But we don’t know the relative effect in relation to other factors, novel diet, changing environment, etc. These questions don’t discount the importance of this published work, they just highlight important nuances that might have changed the rate of change in these lizards.

One of the reasons I really like this paper is the researchers’ approach to testing WHY the toes changed size. Instead of assuming that invasive lizards drive changing behaviors in the native lizards the researchers tested other potential explanations. First the authors tested whether toe size and lamellae number were variable during the life of a lizard but not necessarily heritable traits. To do this they took eggs from parents exposed to invaders and not exposed and raised newborn lizards in the same environment, called a common garden. Lizards from parents exposed to the invaders always had larger toes and more lamellae regardless of the environment they were raised in, showing a heritable difference among the lizards.

Next the researchers tested whether lizards with larger toes had migrated to the islands. Using genetic techniques that measure the number of mutations in gene sequences they found that each island contained lizards that were more related to each other than to lizards on any other island.  The researchers were able to measure 121,973 mutations in these lizards. This is an amazing amount of information, previously science relied on a handful of mutations to identify population level differences, but recent technology has allowed sequencing of many more mutations. This created a very strong test for lizard relatedness within and between islands. The researchers did find a few lizards that had migrated from different islands but overall there was a higher level of relatedness within an island and the islands were very distinct from each other. This is a very exciting result and this data could also be used to identify which genes influence toe size and lamellae number, I expect there will be some more interesting discoveries that come from this data.

Using multiple experiments this study is a powerful example of rapid evolution in response to an invasive species. This is an exciting study because it is actively occurring on a time scale that we can observe and in a real world situation. Many tests of evolution have been conducted in the laboratory but it is difficult to apply laboratory results to complex natural habitats. The invasion of lizards to the spoil islands in Florida offer a great natural experiment to study the mechanisms and speed of lizard evolution.

Here is the full citation for this paper:

Stuart, Y, Campbell, T., Hohenlohe, P., Reynolds, R., Revell, L., Losos, J. (2014) Rapid evolution of a native species following invasion by a congener. Science 346: 463-466.
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    I'm a marine biologist interested in demystifying science. Much of my writing focuses on highlighting recent publications that are especially novel or have promising implications.

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 Raphael Ritson-Williams                                                                             [email protected]



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