Monthly Archives: February 2013

Diversity and Variation .. the key to evolution

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Nicobar pigeon
Photo: Above features a Nicobar Pigeon (Caloenas nicobarica), not a Rock Dove.

The genome of the Rock Dove -aka Pigeon, flying rat, etc.- (Columba livia) has been sequenced. In this article, you can see the great diversity of this invasive species that originated in Eurasia and brought over as a food item.

Mouth full of feathers
Photo: Rock dove as a food item to a Buteo jamaicensis.

Fancy breeds of pigeon were developed over time since they also served as pets to humans. As with other pets, multiple breeds were developed that preferentially display different variations of traits. Sequencing genomes of other organisms is useful for us to understand the common toolkit that all life forms on this planet share and the effects of carrying specific variations of genes.

The article states:

But Dr Mike Shapiro says the pigeon may lead us to some very useful information about ourselves.

“Just about all animals use the same toolkit of genes to build their bodies and to control similar processes during development,” the University of Utah, Salt Lake City, researcher explained.

“By understanding how these processes work in other animals, we can in turn learn more about normal and abnormal variation in humans as well. If you take the gene we identified, this EphB2 gene – this is a gene that has also been implicated in particular types of cancers. It may also have a role in the progression of Alzheimer’s disease,” he told BBC News.

Balance

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Fall

Photo: A dead gray squirrel after a juvenile hawk dropped it in the Mill Pond of Van Cortlandt Park

Here’s an article about an invasive species and the effects on a native species.

In this article, we see that the Gray Squirrel (Sciurus carolinensis), a creature we are all too familiar with, invading the domain of the Red Squirrel (Sciurus vulgaris). These two squirrels are highly related. As we can see, they fall within the same Genus. While the Grey Squirrel species adapted to the North American environment, the red squirrel adapted to Eurasia. Here, we see the effects of introducing an invasive (in the late 1800s) and the effect on a native species. Both squirrels share a similar diet and physical form that is specialized for a very similar environment. So why are the Grays of North America out-competing the Reds? The article points to the resistance of the Grays to pox viruses.Some time in history, resistance to pox viruses was a selective pressure. Those who carried the resistance trait lived and propagated this feature. Now, it is a further advantage when competing with the native Red Squirrel species.

Where else have we seen something like this historically even within the same species? Think about the Columbian Exchange and how that reshaped the booming population of the world at that time.