DNA Evidence Prevents the Extermination of a Species of Iguanas

    In this NY Times article, a Mexican island has been invaded by these spiny-tailed iguanas, or so they thought. Clarion Island houses these iguanas, who were assumed to arrive on the island through humans around the late 20th century. This has never been tested, but because they were considered invasive, the government planned on exterminating them to help the ecosystem. Dr. Mulcahy had seen the iguanas and collected DNA to find that they don't match the sequence of the spiny-tailed iguanas on the mainland. Once he heard about the plan to exterminate, he went to publish the analysis he found to prevent the elimination.

    To analyze the DNA, Dr. Mulcahy and his colleagues compared the mitochondrial DNA of the Clarion iguanas to the mainland iguanas to find a 1.5% difference in the DNA. This meant that the iguanas on the island were distinct enough that they couldn't have recently been introduced to the island. They used data and fossils to find when the split between the two species had happened and found it may have been around 425,600 years ago. This was well before humans arrived in the Americas and implies that the iguanas came to the island on the second-longest known aquatic journey iguanas have gone through.

    These findings came in time to prevent the eradication of these animals and, ironically, the disruption of the ecosystem. The question of how these iguanas went unnoticed has been asked. This could possibly be because of the change in landscape on the island, as settlers brought livestock onto the island that ate away at much of the vegetation. Iguanas are naturally scared and wary of humans and hide when close by, which would leave people unaware of their presence until these hiding spots started running out. 

    This kind of situation happens when the assumption of an animal's role in the ecosystem isn't tested. Research on these iguanas was necessary to prevent a mistake from coming out of extermination, and if it had never been done, there would have been many problems coming about on the island. Assumptions without proof can hurt, and I am glad that someone was able to piece the puzzle together on why they looked and were genetically different from the mainland species.

New Species of Clam Found in Michigan River

A new invasive clam was found in the Illinois River, about 80 miles west of the Michigan River. This new rn aside species brings a lot of questions to mind regarding how exactly it got to the United States of America. Research indicates the species to be in the genus Corbicula, descending from Vancouver and making its way to North America by Asian immigrants. The clams themselves remained a vital source of food for those traveling to America, but the new discovery does not see to be a good one. For starters exact identification is tricky because the sexual reproduction of these clams can start from just a single clam, as a clam can self fertilize itself if it has both male and female sex organs. These clams are also capable of mating with clams within the same taxa, not just species. Another problem this clam brings is a change to the current ecosystem in which it resides. It provides a challenge to other species of clams, even a recently federal endangered species, as they share the same nutrients and food supply. It is marvelous that this one clam species has made its way thousands of miles for new habitation, but undoubtedly it reals havoc on current and future ecosystems in this area and across the nations coast.

Original Article

Don't eat them raw if at all, deadly bacteria!!!

Squirrels Spread by Humans

Grey Squirrel

People have played a bigger role in the spread of grey squirrels in the United Kingdoms than grey squirrels themselves did. DNA profiling has revealed that different squirrel populations in the UK are genetically distinct, or are more closely related to squirrel populations some distance away than to populations close by.  Instead of the squirrels expanding into new habitats themselves, humans have been responsible for their movements, sometimes intentionally and sometimes accidentally.

Red Squirrel

These findings could mean hope for the native red squirrel, which is outcompeted by the grey squirrels in many places. If the spread of squirrels by humans can be stopped, red squirrels in places with no grey squirrel populations may have a chance at surviving.  Can all transport of squirrels by humans actually be stopped? Probably not, because even if all the people actively transporting squirrels (out of good intentions or as pets) were somehow stopped, accidental squirrel transport (in cars, for example) cannot really be controlled.  However, just slowing the spread of grey squirrels may create chances for other solutions to be found.

Genetic Engineering to the Rescue Against Invasive Species

     Invasive species are a major issue when it comes to native ecosystems. There are many factors that come into play when trying to control an invasive species, as where most humans will describe them as just an “exotic” species, in reality they are consuming the resources of the native species and wreaking havoc on the ecosystems. Invasive species are also costly; they cost the United States alone $120 billion dollars annually. Even with the technology that we have today, the invasive species, such as mosquitos, snakes, and carp, are still racking up the damage costs.

     The use of “gene drives” are now being used as an attempt to decline the invasive species’ population numbers by triggering their genetic machinery. Gene drives allow the extinction of a targeted species, in this case the species that is causing the issue. It allows the native ecosystem to return to normal. 

     Kevin Esvelt is a genetic engineer at Harvard University and is the head of using “gene drives.” He and his team warn, however, that this method of genetic modification can cause a lot of issues. They want this technology to be used responsibly. 

     Genes reducing pesticide resistance, hindering a population’s ability to reproduce, or some other desirable impact on a target species is how this technology starts. Previously, the geneticist would insert the target gene into the genome of the invasive species, however there is not guarantee that the modified gene will work. Gene drives come into play here, as they act as a “chauffeur” for the alteration through a population. In most animals, there are two versions of a gene, and thus there is a 50-50 chance of an altered gene being passed onto the next generation. 

     Genetic modification is not a new topic, however CRISPR is. CRISPER (clustered regularly interspaced short palindromic repeats), allow geneticists to target specific genes in the genome. As Esvelt says, “we think that it can engineer the genes in any [sexually reproducing] species.” This technology is as simple as engineering an individual to contain CRISPR and the desired alteration of a targeted gene.

     There are two scenarios how this technology will help with invasive species. The first is that it will increase the likelihood that progeny are males. Because females are imperative to reproduction, having all males will lead to the eventual extinction of the species. The second scenario is knocking out genes that are important for fertility. This means that no progeny will be being produced, thus resulting in the extinction of the species. 

     I feel that this article is very interesting because I want to be a conservation biologist after college. Invasive species is a real issue for conservationists as they are hard to control and they are hard to get rid of once they settle into a new habitat. Having new, groundbreaking techniques like this can help ecosystems get back to their native state, which in turn helps the environment be happy and healthy. 

Original Article

Article about Gene Drives

New Genetic Data for Invasive Lion fish Populations

The popular belief was that the Red Lionfish was introduced to the Western World via an incident in Florida. New genetic research is indicating that that fact is false. The research suggests that there were multiple introduction sites throughout the Caribbean basin.

The red lionfish is a non-native invasive predatory species in the Western hemisphere originally from the Indo-Pacific region. Since they have no native predators in the Atlantic/Caribbean/South Atlantic they are quickly destroying habitats and wreaking havoc across already unstable marine environments, especially coral reefs.

This data is helping researchers track the Red Lionfish populations as well as if there are more/new introduction sites. The USGS recently conducted a survey taking animals from 14 countries within the Greater Caribbean Basin and Western Atlantic. The genetic differences between fish from difference sites are great enough to suggest they were dispersed from multiple introduction sites. This genetic data is helping scientists understand how the lionfish are spreading and what would be the most effective method of removal.

I think that this article was important because our coral reefs are already struggling with climate change as well as pollution as it is. The reefs do not need another factor to make them even more barren. It is important to monitor and control these populations as the lionfishes' ranges are beginning to expand past the warm tropical waters into more of the Northern Atlantic.

Link: http://www.sciencedaily.com/releases/2015/04/150423154631.htm

Genetics Provides New Clues about Lionfish Invasion

                The U.S. Geological Survey has reported that new genetic data suggests the red lionfish invasion in the Caribbean Basin and Western Atlantic started in multiple locations and not just one as previously believed. Genetically unraveling the progression of the red lionfish invasion and determining if introductions are still occurring could assist in guiding response and control efforts for this and other invasive species. Lionfish are native to the indo-Pacific region and are well known as a predatory invasive species that could disrupt local marine food webs. Researchers found that unique regional genetic patterns separated the studied area into northern and southern regions, with the split occurring near the Bahamas. Due to these regional genetic differences, researchers suspected multiple introductions. Studying the genetic strains across the regions gives researchers insight to how these fish are spreading. Continued releases would increase the potential for more genetically diverse red lionfish to join the current population and expand their range beyond current boundaries.  The broad dispersal of the red lionfish may in part be due to their reproductive habits. Following spawning, larvae can disperse long distances via ocean currents.  In the United States, federal and state agencies are working together to control this invasive species through the Aquatic Nuisance Species Task Force.

                It’s interesting to see how the genetic data was used to determine if there were multiple locations of introduction for this invasive species. This was done by comparing the different genetic strains and identifying the regional subpopulations. Similar use of genetic data could be useful in other cases that involve invasive species.

http://www.usgs.gov/newsroom/article.asp?ID=4194#.VTAs-CHBzGc

http://www.telegraph.co.uk/travel/destinations/centralamericaandcaribbean/saintlucia/11384301/Fighting-the-Caribbeans-lionfish-invasion.html