(Roughly) Daily

Posts Tagged ‘genetics

“Not with a bang, but with a whimper”*…

 

death

Death Table from Tuberculosis in the United States, prepared for the International Congress on Tuberculosis, September 21 to October 12, 1908. Image: U.S. National Library of Medicine

 

Recent history tells us a lot about how epidemics unfold, how outbreaks spread, and how they are controlled. We also know a good deal about beginnings—those first cases of pneumonia in Guangdong marking the SARS outbreak of 2002–3, the earliest instances of influenza in Veracruz leading to the H1N1 influenza pandemic of 2009–10, the outbreak of hemorrhagic fever in Guinea sparking the Ebola pandemic of 2014–16. But these stories of rising action and a dramatic denouement only get us so far in coming to terms with the global crisis of COVID-19. The coronavirus pandemic has blown past many efforts at containment, snapped the reins of case detection and surveillance across the world, and saturated all inhabited continents. To understand possible endings for this epidemic, we must look elsewhere than the neat pattern of beginning and end—and reconsider what we mean by the talk of “ending” epidemics to begin with…

Contrary to hopes for a tidy conclusion to the COVID-19 pandemic, history shows that outbreaks of infectious disease often have much murkier outcomes—including simply being forgotten about, or dismissed as someone else’s problem: “How Epidemics End.”

* T. S. Eliot, “The Hollow Men”

###

As we contemplate the end, we might send insightful birthday greetings to Nettie Maria Stevens; she was born on this date in 1861.  A geneticist– and one of the first American women to achieve recognition for her contributions to scientific research– she built on the rediscovery of Mendel‘s paper on genetics (in 1900) with work that identified the mechanism of sexual selection: its determination by the single difference between two classes of sperm—the presence or absence of (what we now call) an X chromosome.

220px-Nettie_Stevens source

 

“Just as the twig is bent, the tree’s inclined”*…

 

Crown shyness

 

In certain forests, when you look up you will see a network of cracks formed by gaps between the outermost edges of the tree branches. It looks like a precisely engineered jigsaw puzzle, each branch growing just perfectly so it almost—but not quite—touches the neighboring tree. This beautiful phenomenon is called crown shyness.

Crown shyness doesn’t happen all the time, and scientists aren’t completely certain why it happens at all…

The forest keeps its secrets… Despite decades of study– and a profusion of postulation– no one yet fully understands “The Mysteries of Crown Shyness.”

* Alexander Pope

###

As we keep to ourselves, we might spare a thought for Gregor Johann Mendel; he died on this date in 1884. After a profoundly-unpromising start, Mendel became a scientist, Augustinian friar, and abbot of St. Thomas’ Abbey in Brno, Moravia (today’s Czech Republic).  A botanist and plant experimenter, he was the first to lay the mathematical foundation of the science of genetics (of which he is now consider the “Father”).  Over the period 1856-63, Mendel grew and analyzed over 28,000 pea plants.  He carefully studied the height, pod shape, pod color, flower position, seed color, seed shape and flower color of each– and from those observations derived two very important generalizations, known today as the Laws of Heredity.

 source

 

Written by LW

January 6, 2020 at 1:01 am

“History never really says goodbye. History says, ‘See you later.'”…

 

tiger

Surprised! Henri Rousseau, 1891

In An Autobiography, published in 1939, R.G. Collingwood offered an arresting statement about the kind of insight possessed by the trained historian. The philosopher of history likened the difference between those who knew and understood history and those who did not to that between ‘the trained woodsman’ and ‘the ignorant traveller’ in a forest. While the latter marches along unaware of their surroundings, thinking ‘Nothing here but trees and grass’, the woodsman sees what lurks ahead. ‘Look’, he will say, ‘there is a tiger in that grass.’

What Collingwood meant was that, through their familiarity with people, places and ideas, historians are often equipped to see how a situation might turn out – or at least identify the key considerations that determine matters. Collingwood’s musings implied an expansive vision of the role historians might play in society. Their grasp of human behaviour, long-term economic or cultural processes and the complexities of the socio-political order of a given region of the world meant that they could be more than just a specialist in the past. By being able to spot the tiger in the grass, historians might profitably advise on contemporary and future challenges as well…

Can the study of the past really help us to understand the present?  Robert Crowcroft argues that it can: “The Case for Applied History.”

* Eduardo Galeano

###

As we look to the past, we might spare a thought for Martha; she died on this date in 1914.  As she was the last known passenger pigeon, her death meant the extinction of the species.

(De-extinction efforts are underway.)

Martha

 source

 

Written by LW

September 1, 2018 at 1:01 am

“Energy is liberated matter, matter is energy waiting to happen”*…

 

We’ve certainly come a long way since the ancient Greek atomists speculated about the nature of material substance, 2,500 years ago. But for much of this time we’ve held to the conviction that matter is a fundamental part of our physical universe. We’ve been convinced that it is matter that has energy. And, although matter may be reducible to microscopic constituents, for a long time we believed that these would still be recognizable as matter—they would still possess the primary quality of mass.

Modern physics teaches us something rather different, and deeply counter-intuitive. As we worked our way ever inward—matter into atoms, atoms into sub-atomic particles, sub-atomic particles into quantum fields and forces—we lost sight of matter completely. Matter lost its tangibility. It lost its primacy as mass became a secondary quality, the result of interactions between intangible quantum fields. What we recognize as mass is a behavior of these quantum fields; it is not a property that belongs or is necessarily intrinsic to them.

Despite the fact that our physical world is filled with hard and heavy things, it is instead the energy of quantum fields that reigns supreme. Mass becomes simply a physical manifestation of that energy, rather than the other way around…

Modern physics has taught us that mass is not an intrinsic property: “Physics Has Demoted Mass.”

* Bill Bryson, A Short History of Nearly Everything

###

As we watch all that is solid melt into air, we might spare a jaundiced thought for Trofim Denisovich Lysenko; he died on this date in 1976.  A Soviet biologist and agronomist, he believed the Mendelian theory of heredity to be wrong, and developed his own, allowing for “soft inheritance”– the heretability of learned behavior. (He believed that in one generation of a hybridized crop, the desired individual could be selected and mated again and continue to produce the same desired product, without worrying about separation/segregation in future breeds.–he assumed that after a lifetime of developing (acquiring) the best set of traits to survive, those must be passed down to the next generation.)

In many way Lysenko’s theories recall Lamarck’s “organic evolution” and its concept of “soft evolution” (the passage of learned traits), though Lysenko denied any connection. He followed I. V. Michurin’s fanciful idea that plants could be forced to adapt to any environmental conditions, for example converting summer wheat to winter wheat by storing the seeds in ice.  With Stalin’s support for two decades, he actively obstructed the course of Soviet biology and caused the imprisonment and death of many of the country’s eminent biologists who disagreed with him.

Interestingly, some current research suggests that heritable learning– or a semblance of it– may in fact be happening, by virtue of epigenetics… though nothing vaguely resembling Lysenko’s theory.

 source

 

Written by LW

November 20, 2017 at 1:01 am

“All of today’s DNA, strung through all the cells of the earth, is simply an extension and elaboration of [the] first molecule”*…

 

The first biological teleporter sits in a lab on the lower level of the San Diego building that houses Synthetic Genomics Inc. (SGI), looking something like a super-sized equipment cart.

The device is actually conglomeration of small machines and lab robots, linked to each other to form one big machine. But this one can do something unprecedented: it can use transmitted digital code to print viruses.

In a series of experiments culminating last year, SGI scientists used genetic instructions sent to the device from elsewhere in the building to automatically manufacture the DNA of the common flu virus. They also produced a functional bacteriophage, a virus that infects bacterial cells.

Although that wasn’t the first time anyone had made a virus from DNA parts, it was the first time it was done automatically, without human hands.

The device, called a “digital-to-biological converter” was unveiled in May. Though still a prototype, instruments like it could one day broadcast biological information from sites of a disease outbreak to vaccine manufacturers, or print out on-demand personalized medicines at patients’ bedsides…

… or project life-as-we-know it into outer space. More at “Biological Teleporter Could Seed Life Through Galaxy.”

* Lewis Thomas, The Medusa and the Snail

###

As we beam up, we might spare a thought for Sidney Walter Fox; he died on this date in 1998.  A biochemist, he was responsible for a series of discoveries about the origin of life.  Fox believed in the process of abiogenesis, by which life spontaneously organized itself from the colloquially known “primordial soup,” poolings of various simple organic molecules that existed during the time before life on Earth.  In his experiments (which possessed, he believed, conditions like those of primordial Earth), he demonstrated that it is possible to create protein-like structures from inorganic molecules and thermal energy.  Dr. Fox went on to create microspheres that he said closely resembled bacterial cells and concluded that they could be similar to the earliest forms of life or protocells.

 source

 

Written by LW

August 10, 2017 at 1:01 am

%d bloggers like this: