The phases of the cell cycle, particularly that of mitosis, were taught in college as part of my studies in biology. The cell cycle is a fundamental process for all organisms and constantly happens within our bodies. While cells generally spend most of the time in interphase, many scientists focus on what happens as the cells prepare to divide from one cell into two. Mitosis, the part of the cell cycle that refers to cell division, is subject to extensive regulation to ensure all materials and genetic information are sound and ready to segregate correctly. If there is damage to the chromosomes, the cells will halt cell division. Continue reading “Stop Targeting Lasers on My Chromosomes!”
General
From Gray Wolf to Bulldog: Changes to the Dog Brain as Humans Reshape it’s Head
We humans are masters of reinvention. And we love our dogs. Over the past 12,000 years we’ve mixed that love of innovation and love of dogs, to create a species with more physical variation than any other species on Earth.
Much of this innovation has served us well. Domesticated dogs have protected our livestock and our homes, helped us hunt and retrieve game, and carried our belongings. And come the cold, snowy weather season, or a pesky avalanche, it’s nice to know that a Saint Bernard dog may be nearby with a cask of brandy on it’s collar. Seriously, rescue dogs have aided many a lost, stranded or endangered person.
Dog breeding has served to enhance the good traits as well as to remove from a dog breed, certain bad genetic components, such as predisposition to genetically-linked diseases, as well as traits such as hip dysplasia, and eye or cardiac anomalies.
As for the variations in type, dog breeding has developed such variety as a nearly hairless dog, dogs with highly shortened faces, and dogs with so much hair that their faces are difficult to distinguish.
The extremes affect height, weight, hair (or lack of hair, as is the case of the Chinese Crested dog). For that matter, many dogs have a haircoat that is shed, similar to wolves, coyotes and fox, while others (poodles and many terriors) have hair, that is not shed, but rather must be trimmed.
If you know a greyhound or collie dog, you know the long–headed feature, similar to that of the original dog ancestor, the gray wolf. This morphological feature is described as dolichocephalic (long-skulled). On the other hand, if you happen to be supporting the habits of, say a Neopolitan Mastiff or a Pug dog, that makes you in the caregiver of a brachiocephalic canine, that is a short-skulled dog. Such dog breeds show a greater deviation from the ancestral gray wolf than a long-skulled dog. And as a recent study shows, more than just the head shape of brachiocephalic dogs has changed.
A July 2010 report in PLos ONE (Roberts, T., et al.; 1), noted that the extreme diversity in shape and size found in domestic dogs extends to the canine skull.
The authors set out to determine if these apparent physical features, skull shape differences, translated to differences in brain structure.
Cephalic index (CI) of the study dogs was calculated from digital measurements of length and width of the skull. As a starting point, the authors used the the gray wolf, for which various reports listed a cephalic index of 50.9 to 51.9.
Eleven dogs, representing various breeds and crossbreeds were used. The dogs were from shelters, and had been recently euthanized, for reasons other than the purpose of this study. An additional two dogs used were English Springer Spaniels, who were also not euthanized for this study, rather were measured while under sedation.
The cephalic indices reported ranged from 42.2 in a greyhound to 87.2 in a shih tzu cross, the higher number indicating a shorter skull shape. The authors noted that body size and weight were closely related to CI in the domestic dogs studied.
The rather dramatic sagittal scans in the report, show a comparison of a brachiocephalic and dolichocephalic dogs with the brain outline and center of mass marked in red, and the olfactory bulb in yellow. The authors (in Figure 2) showed the two extremes of very short and very long-skulled dogs, with the brain positional differences no less striking.
The olfactory bulb was found to be positioned differently in dogs with a shortened skull. These dogs showed a definite ventral or forward (looking at a cross-section from the front of the nose to the back of the skull) shift of the brain, as well as of the olfactory bulb. Thus the authors note a strong correlation between a high CI and both central axis rotation ventrally, as well as a ventral rotation of the olfactory bulb.
This dog owner would be very interested in whether shorter–skulled dogs have behavorial changes that could be connected to their breeding. Let’s face it, the next time our dogs lunge at the dog walking by, it would help to be able to shrug and call out, “Sorry, short head”. Or, “He can’t help it, he was bred that way.”
Sadly, that’s not how it works. Once assuming ownership of a certain type of dog, the onus is on the owner to teach the dog what is and is not acceptable behavior.
But if future studies may show a connection between cephalic index of particular dog breeds and behavioral characteristics, that information might be useful in choosing a dog. Say you wanted a dog for protection and it had been proven that a pug’s head shape was not ideal for guard dog-type behavior. You would instead choose a Collie. Umm… make that a Doberman Pinscher. Of course Italian Greyhounds are also long-headed dogs, although known more for speed of flight, than for protective tendencies.
Reference
1. Roberts T, McGreevy P, & Valenzuela M (2010). Human induced rotation and reorganization of the brain of domestic dogs. PloS one, 5 (7) PMID: 20668685
Prairie Dogs: Small Creatures, Big Vocabulary
It is summer, July already! Vacation time for kids and the people that love them.
Though many years past, I recall fondly one of our first family trips to the Black Hills of South Dakota. While en route, we stopped in the Badlands National Park. Though the Badlands might appear a barren, treeless desert (and believe me, in the western summer sun it feels that way), the area is loaded with animal life. Particularly intriguing to me were some small rodent residents, the prairie dogs.
Continue reading “Prairie Dogs: Small Creatures, Big Vocabulary”There’s an Evil Hand Afoot and Other Ways to Spice Up Your Technical Literature
The Bulwer-Lytton Fiction Contest challenges entrants to compose the opening sentence to the worst of all possible novels. Dennis Pearce, the runner up in the 2010 Detective story category, penned the following words:
As Holmes, who had a nose for danger, quietly fingered the bloody knife and eyed the various body parts strewn along the dark, deserted highway, he placed his ear to the ground and, with his heart in his throat, silently mouthed to his companion, “Arm yourself, Watson, there is an evil hand afoot ahead.”
Pondering this particularly good piece of bad writing, I found myself wondering what would happen if we used this over-the-top style in tehnical literature including scientific articles and protocols. Could it help to draw attention to important details and entertain the reader at the same time? But since the goal of instructional materials is to be clear, concise and to the point, there’s not usually much room for just-for-fun content.
Or is there?
Continue reading “There’s an Evil Hand Afoot and Other Ways to Spice Up Your Technical Literature”The Ongoing Legacy of the Human Genome Sequence
When the first draft sequence of the human genome was announced, I was a research assistant for a lab that was part of the Genome Center of Wisconsin where I created shotgun libraries of bacterial genomes for sequencing. Of course, the local news organizations were all abuzz with the news and sought opinions on what this meant for the future, including that of the lab’s PI and oddly enough, my own. While I do not recall the exact words I offered on camera, I believe they were something along the lines of this is only the first step toward the future of human genetics. Ten years later, we have not fulfilled the potential of the grandiose words used to report the first draft sequence but have gained enough knowledge of what our genome holds to only intrigue scientists even more.
Continue reading “The Ongoing Legacy of the Human Genome Sequence”
Mate Selection at Frog Cocktail Parties: Keep it Short, Low, Loud, and Stand Out from the Crowd (Oh, and have a colorful vocal sac, too)
When I lived in Sioux City, IA, I had the opportunity of hanging out with a zoologist who studied the Plains Spadefoot Toad (Spea bombifrons). I would go out with her on nighttime listening surveys, and we would slowly drive the gravel farm roads in the middle of nowhere, weaving from one side to the other as we dodged hopping frogs and toads, and I would be amazed as the clamor of these calling anurans rattled my eardrums.
Just last week in Madison, as I took my lunchtime walk, I passed by a roadside wetland, and my ears filled with the calls of Chorus frogs, singing with all their one-inch might in hopes of attracting a mate. And, later that evening, as my daughter and I weeded our garden at home, I heard the crisp bell trill of two American toads carrying over the chorus frogs in the neighborhood.
Congresses of snoring Spadefoot Toads. In-your-face Copes Gray Tree Frogs. Peepers, Chorus Frogs and and Leopard Frogs. The evenings are noisy when the temperatures moderate and these frogs and toads come out to call. The din of the local roadside wetland begins to resemble the din of the local roadside bar, in more ways than one as it turns out.
Continue reading “Mate Selection at Frog Cocktail Parties: Keep it Short, Low, Loud, and Stand Out from the Crowd (Oh, and have a colorful vocal sac, too)”An Interview with Ed Himelblau, Scientist and Promega Cartoonist
Many visitors to the Promega Web site enjoy the Cartoon Lab, the repository of the creative illustrations of Ed Himelblau updated several times a year. Recently, I had a chance to gain some insight about the man behind the cartoons.
Sara Klink: Could you give some background information about yourself?
Ed Himelblau: I was born in Chicago but grew up in San Diego. I went to UCSD [University of California at San Diego] and majored in biology and minored in art. I liked molecular biology and working in labs so I decided to go to grad school. I went to the University of Wisconsin at Madison to get a Ph.D. in the Cell and Molecular Biology program. My first academic job was teaching biology at Southampton College in New York. After several years on Long Island, I moved to my current job teaching and doing research in the Biological Sciences Department at Cal Poly [California Polytechnic State University] in San Luis Obispo, CA.
S.K.: Why did you decide to become a scientist?
E.H.: Playing in tidepools as a kid had something to do with it. As an undergraduate I thought working in a lab sounded cool. When I started working in a lab, I thought the work was interesting and the people were a lot of fun to be around. Then I started to appreciate what it really meant to do experiments and learn about how plants grow and develop.
Use Parallel Structure to Guide the Reader
Getting What You Want from Your Science Writing Part X
Parallel construction signals to the reader that two ideas are of equal importance. If two or more ideas or items are connected by a coordinating conjunction such as “and”, “but” or “or”, then those ideas should be expressed in parallel or equivalent grammatical constructs. Items and ideas of equal importance should be presented using equivalent grammatical structures. Items in a list should be parallel: all verbal phrases, all nouns, etc. Parallel construction guides your reader and helps your reader organize concepts on a first read of your text. Continue reading “Use Parallel Structure to Guide the Reader”
Antibody Art
There are many levels on which science can be a beautiful thing. Some of these are quite abstract, like the experimental result that exactly proves the theory, the perfect order revealed in a mathematical equation, or the exquisite sensitivity seen in regulation of a signaling pathway. On another level the output of an experiment itself can have a physical beauty of its own. For example, immunofluorescence and immunocytochemistry technologies can generate results that not only reveal information about the subject of the experiment, but also can be quite spectacularly beautiful. Here are a few favorites of mine:
Degrees of Silence
Listen carefully. Do you hear that?
“What am I trying to hear?” you might ask.
Nothing.
In life, there is constant noise. At home, there is the the hum of the refrigerator, furnace or air conditioner, the faint sounds of traffic outside and a dozen other sources of background noise. At my desk at work, I hear muffled voices of people in the hall, computer printers printing and the clicking of keyboards as people type. Noise is so pervasive that often I don’t notice it anymore. Continue reading “Degrees of Silence”
