Tag Archives: genomics

Surprises From the Past: The Revelations of Ancient DNA

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Forest Tundra on the Taymyr Peninsula between Dudinka and Norilsk near Kayerkan, Russia, taken in 2016. Was it always look like this? Should it look like this?
Image Credit: Ninaras, CC BY 4.0, Image Cropped

Although obtaining ancient DNA can be quite a headache, it is a very rewarding headache. After all the work that goes into obtaining DNA from a bone, fur, hair, or Viking’s leftover meal, researchers have to make sense of the apparent random sequence of nucleotide bases. But once that’s taken care of, there are a series of really interesting questions we can start to answer. Were DNA strands that are present in the modern times inherited from the past? How similar are today’s species to their forebears? Where is my pet velociraptor?

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Preserving Biological Heritage: The Importance of Type Specimens

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Museum collections may seem like they’re just for display, but they often house important biological information (Image Credit: Andrew Moore, CC BY-SA 2.0, Image Cropped)

Last September, the devastating news of a fire in Brazil’s National Museum in Rio de Janeiro hit the world. The fire destroyed most of the collection, including about 5 million insect specimens. Many of the samples were holotypes, a subset of type specimens which are particularly valuable to the scientific world. If you want an indication of just how valuable, some researchers even charged back into the building while it was on fire to rescue these specimens, saving about 80 % of the mollusc holotypes.

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Does Invading Change You?

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The red lionfish, an aggressive, fecund, and competitive species invasive to the Atlantic Ocean (Image Credit: Alexander Vasenin, CC BY-SA 3.0, Image Cropped).

The genomics of invasion: characterization of red lionfish (Pterois volitans) populations from the native and introduced ranges (2019) Burford Reiskind et al., Biological Invasions, https://doi.org/10.1007/s10530-019-01992-0(0123456789

The Crux

Invasive species are one of the most destructive forces and largest threats to native ecosystems, second only to habitat loss. The “how” and “when” of a species invading new habitats is obviously important, and as such many studies focus on if invasive species are present and if they are spreading. Yet these studies often disregard the mechanisms behind why a species is spreading or succeeding in these new environments. The mechanisms are important here, because by and large most invasive organisms will have very small populations sizes, leaving them vulnerable to stochastic events like environmental flux, disease, and inbreeding depression.

Two key paradoxes of invasive species are that these small groups of invasive organisms tend to not only have more genetic diversity than the native species (making them more adaptable to environmental change), but they are also able to outcompete the native organisms, despite having evolved in and adapted to what may be a completely different environment. The authors of this study used genomic approaches to address and try to understand these paradoxes.  Read more

Changing with the Climate

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An immature female blue-tailed damselfly (Ischnura elegans)

An immature female blue-tailed damselfly (Ischnura elegans) (Image Credit: Charles J Sharp, CC BY-SA 4.0, Image Cropped)

Signatures of local adaptation along environmental gradients in a range-expanding damselfly (Ischnura elegans) (2018) Dudaniec et al., Molecular Ecology http://doi:10.1111/mec.14709

The Crux

Terrestrial organisms aren’t always stationary entities, they often move around the landscape searching for food, potential mates, or more ideal environments. Over time, these movements may introduce the species into new environments, as some change allows the species to expand their historical range.

An interesting aspect of this shifting of the species range is how the organisms at the edge of the distribution are maladapted to the novel environments, as most of the species will be adapted to conditions at the core of the species range. To overcome this, they must adapt to the new conditions. Successful adaptation is dependent on changes in gene frequencies away from the historical genotypes, with an increase in genes that promote survival in the new habitats. The authors in this study used molecular techniques to identify genes that new environments might select for.

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