Thursday, April 3, 2014

Black of Hair: The Genetics of Westeros

It's back! SundaySundaySunday!

*Fangirl scream!*

Are you a Game of Thrones fan? I certainly hope so. We'll have so much more to talk about that way. I've been squirreling this topic away for a while now, but with the return of the show I thought I'd air it out. If you are a fan of the books and the show then you'll know that amongst the plethora of characters in Westeros there are some rather dubious things going on. This is where I yell SPOILER ALERT in the hopes that I won't ruin the surprises for the unsuspecting. You've been warned.

Westeros doesn't exactly have genetic profiling, but there are some features that don't really need it so much (ahem...all those blond Lannisters). Although, considering the protection and money you get from being a Lannister, the importance of being related to the Targaryens, and if you are a child of Robert Baratheon, it is probably good to know your genetic make up a bit better.

Way back in Season 1, Eddard "Ned" Stark started investigating the death of Lord Jon Arryn. This led him to The Lineages and Histories of the Great Houses of the Seven Kingdoms, an old book detailing the sigils, lineages, and appearances of the members of each noble House. This ultimately lethal path culminates in three simple words: "Black of hair..." Words that not only spelled out death for Ned but also led to the demise of most of his relatives. Ned was actually very clever, taking those words and employing the same logic behind those lovely Punnet Squares we all had to learn in biology class, drawing conclusions about Baratheon and Lannister genetics. A genotype from phenotype approach, if you will.

In the above comic, we are assuming that Robert was homozygous dominant (BB) for black hair. Had there been a relative that passed on a recessive blond hair allele (b) to him then he would be heterozygous (Bb) for the hair color trait. As a heterozygote, Robert would have black hair, but each of his children from a homozygous recessive (bb) mother would have a 2 in 4 chance of being blond. It is important to point out that this fifty percent chance is applied to each child independently, not that half of his children would be blond.

When it comes to an evidence-based conclusion, Ned didn't exactly have a large sample size. Considering Robert's philandering ways, the number of children produced was most certainly very large. But, Ned only looked at Cersei's children (Joffrey, Tommen, and Myrcella...all blond), the story of Cersei's first child ( hair), Gendry (black haired bastard of Robert by a tavern wench - her hair color unknown), and (sorta) Barra (bastard child by Mhaegan - a blond - of Petyr Baelish's employ). If Robert was homozygous dominant (BB) and the mother of each of his children was homozygous recessive (bb) then 100 percent of his children would be heterozygous (Bb) and black haired.

That said, Ned did have a good source in the Lineages and Histories book that describes all members of House Baratheon as "black of hair," except for the "golden headed" Joffrey (some minor TV vs. book differences here, but that lead to the same conclusions on my and Ned's part). By all members, I'm assuming this counts siblings, aunts, uncles, cousins, etc. Had there been a blond in there somewhere it would have given more credence to the heterozygous argument.

For the sake of length, and the fact that I really just wanted to post that funny little comic, I kept things simple. Genetics is oh-so-much-more complicated. If you want to read more about the genetics of Westeros then I'll draw your attention to two very well written articles over at Mad Art Lab:

The first nicely lays out the argument that "after enough generations of marrying into families like Lannister and Targaryen, we would expect some of the Baratheon kids to have blond hair, but they don't. That doesn't sound like Mendelian inheritance. What it does sound like is another phenomenon, called paramutation."

check out Genetics in Game of Thrones: "The Seed is Strong"

The next brings up many of the same points that I do. However, it spends more time asking what if you could look at the genes of the families? Essentially, what if we could give Robert, Cersei, Jamie, their children, etc. paternity tests? And how do you interpret the results?

check out Genetics in Game of Thrones: Forensics

And finally, for all you need to know about Game of Thrones check out the Game of Thrones Wiki

Monday, March 24, 2014

Interactive Lunar Mosaic

Are you ready for some interactive spacey goodness? Stupid question, I know.

NASA recently released their Lunar Reconnaissance Orbiter Camera (LROC) Northern Polar Mosaic (LNPM). Using two Narrow Angle Cameras aboard their Lunar Reconnaissance Orbitor (LRO) along with additional information about the moon's topography from LRO's Lunar Orbiter Laser Altimeter and gravity information from NASA's Gravity Recovery and Interior Laboratory (GRAIL), they were able to create the largest high resolution mosaic of our moon’s north polar region. This mosaic is comprised of 10,581 six-and-a-half feet (two-meters)-per-pixel images covering an area equal to more than one-quarter of the United States. Put together, the entire image measures 931,070 pixels square. Do the math? That's almost 867 billion pixaels total!

And here's the interactive part: web viewers (that's you) can zoom in and out, and pan around an area. There is enough detail in these images that you can see textures and subtle shading of the lunar terrain, and the consistent lighting throughout the images makes it easy for you to compare different areas.

Also check out more information about LRO at NASA's LRO website

and look through the complete collection of LROC Images

and NASA's Press Release "NASA Releases First Interactive Mosaic of Lunar North Pole"

(image via NASA's press release)

Tuesday, March 18, 2014

Monday, March 17, 2014

Friday, March 14, 2014

The Charge of the Crazy Ant: Chemical Warfare Between Invading Species

LeBrun, Jones, and Gilbert (2014) Figure 1A
I’ll be the first to admit that I've been a little blog-negligent lately. Even when all of the ice and snow we've gotten here on the East Coast forced me to stay inside I just binge watched shows on Netflix instead. I’m not sure what brought me out of my procrastination funk and compelled me to do a little reading and writing. If you've been following the Facebook page then you've been getting a lot of yummy sciency tidbits, but it’s time for me to get back on the hard science wagon. I think I’ll start off with a great couple of papers about ant chemical warfare.

These papers focus on invasive ants, a big problem in many regions. To really grasp one of the underlying aspects of their warfare strategies, you must first understand the basics of an invasive species. Start by recognizing the difference between a native species and an exotic species. Put simply, a native species occurs naturally (or natively) to a habitat and an exotic species does not. Exotics can come in any biological form, but they are not necessarily a problem to their new habitat (think: earthworms). It’s when an exotic species becomes an invasive species that there is a problem because invasives cause environmental, economic, and/or human health harms. The reason for this is that they did not evolve together with the ecosystem in which they find themselves. There are no checks and balances in place to curb their population growth, things like predators, parasites, and competitors. Their unnaturally large population numbers then become harmful to the native species that suddenly have to deal with and compete against them, dramatically altering the community and habitat.

It is often the case that multiple species invade a region. Throughout the rest of this post I’ll be discussing new papers by Michael Kaspari and Michael Weiser and by LeBrun, Jones, and Gilbert (specifically at the latter) that take a look at just such a case in ants. The red imported fire ant (Solenopsis invicta) first came to the United States from South America around 1930. This species is far more aggressive than your typical American ant, not only in how they like the bite the hell out you (that’s a lot of personal experience talking) but also in their predatory abilities and landscape re-engineering. Now enter the tawny crazy ant (Nylanderia fulva). This new exotic invasive species was transported to the southeastern U.S. in the early 1980s and has begun to spread.. These two species have common source assemblages, their native ranges overlapping in northern Argentina, Paraguay, and southern Brazil. Until the introduction of crazy ants, the fire ant has enjoyed an uninterrupted domination of the native grassland ant assemblages. But now that the crazy ant has arrived on the scene they are displacing the fire ants. Why is this?

Since the fire and crazy ants have overlapping native habitats, they have evolved to compete directly for resources. The tawny crazy ant easily expels the fire ant from any food items it controls, up to 93 percent of the time. Also, tawny crazy ants have often been found living inside fire ant mounts, having usurped the mound and evicted the owners. Fire ants are strong and resilient and so the crazy ants must have a strong competitive advantage.

Now, finally, we get to the meat of the post: chemical warfare. If you've been stung by a fire ant (or ants, plural, as is usually the case) then you know that they pack a wallop! They have an alkaloid venom called Solenopsin that to humans causes a painful, fiery sting, and to other ants acts as a topical insecticide. The crazy ants do not have stingers but instead possess an acidopore (a specialized exocrine gland) on the end of the abdomen that sprays their venom into a mist of formic acid. They will charge into masses of fire ants misting as they go. But the fire ants don’t just stand by idly to be sprayed with venom and die, they fight back. The fire ants “gaster flag,” extruding venom from their stingers and dabbing it onto a nearby attacking ant. Normally this would result in the death of said ant. However, LeBrun and his colleagues have observed what they are calling a “detoxifying behavior” in the attacking tawny crazy ants. In this behavior, an afflicted ant stands on its hind legs, run its front legs through its mandibles, and grooms itself vigorously, periodically reapplying its acidopore to its mandibles (check out the video!).

To test this behavior the researchers conducted a series of experiments to see if there is really a detoxifying component, to see where it is coming from, and to evaluate the species-level specificity of the behavior. For the first they staged antagonistic interactions between the two species, sealing a portion of the crazy ant acidopores, and then observing afflicted individuals for behavior and survivorship. They found that those tawny crazy ants that had had their acidopores sealed had a low survival rate (only 48 percent). However, those with working acidophores had a 98 percent survival rate, supporting the detoxifying hypothesis. The Dufour’s and venom glands (exocrine glands used for communication and defense) both duct to the acidopore in this species. To see where the detoxifying agent was coming from they applied solutions of fire ant venom and tawny crazy ant glandular products to Argentine ants (Linepithema humile), which are morphologically similar to crazy ants but do not have the detoxifying capability. These tests showed the venom gland of the crazy ant to contain the detoxifying agent. When the crazy ant’s formic acid was tested it was found to be the compound responsible for detoxifying fire ant venom.

The production and application of this antidote is a potentially costly endeavor for the crazy ants. Yes, it is the difference between life and death, but when to apply it must be considered. Why use a costly resource if you don’t have to? The authors conducted a series of ant interaction tests where they had crazy ants interact independently with eight Texas ant species including fire ants, observing when the crazy ants chose to apply their detoxifier. They found that after chemical conflict with fire ants, crazy ants detoxified themselves with almost 7 times more frequently than the average response to other ant species. This suggests that this detoxifying behavior is specifically adapted to competition with fire ants, and it is probably a key factor in the displacement of invasive fire ants now underway in the southern United States.

ResearchBlogging.orgLeBrun, E., Jones, N., & Gilbert, L. (2014). Chemical Warfare Among Invaders: A Detoxification Interaction Facilitates an Ant Invasion Science, 343 (6174), 1014-1017 DOI: 10.1126/science.1245833

ResearchBlogging.orgKaspari, M., & Weiser, M. (2014). Meet the New Boss, Same as the Old Boss Science, 343 (6174), 974-975 DOI: 10.1126/science.1251272

U.S. Fish and Wildlife Service's page on Invasive Species
The University of Texas at Austin Fire Ant Project
Texas A&M AgriLife Research Extension page on Tawny Crazy Ants

Wednesday, March 5, 2014

Science Heroes

I recently received this video in a promotional email by Life Technologies. I haven't posted a creative, sciency ad in a while. Although, I've yet to find an ad that surpasses BioRad's The PCR Song or even Eppendorf's epMotion ad.

Tuesday, March 4, 2014

Science Knitting

Science Dump recently posted some creative science knitting projects. Here are a few of my favorites from their selection.

Happy Bacteria

Frog Dissection






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