re-coloured picture of Darwin

Extinct Giant Tortoise May Still Be Alive in Galapagos

A hybrid C. becki tortoise. Photo: Claudio Ciofi

From Wired.com
by Brandon Keim

Genetic traces of a supposedly extinct giant tortoise species have been found in living hybrids on the Galapagos island of Isabela.

A few pure Chelonoidis elephantopus almost certainly still exist, hidden in the island’s volcanic redoubts. The hybrids have so much C. elephantopus DNA that scientists say careful breeding could resurrect the tragically vanished behemoths.

“To our knowledge, this is the first rediscovery of a species by way of tracking the genetic footprints left in the genomes of its hybrid offspring,” wrote researchers led by Yale University biologists Ryan Garrick and Edgar Benavides in a Jan. 9 Current Biology paper.

At the beginning of the 16th century, before humans arrived, an estimated 250,000 giant tortoises representing 15 different species lived in the Galapagos. Once fully grown, the tortoises had no natural predators — except people.

For whalers and pirates, the slow-moving animals were like walking grocery stores. They weighed up to 900 pounds; their flesh was tasty and rich in oil. They could survive for months, even years, without eating or drinking, and sailors stored tortoises alive in the hulls of their ships for future consumption.

By the time a young Charles Darwin surveyed the tortoises, they were being indiscriminately slaughtered. (“The inhabitants believe that these animals are absolutely deaf; certainly they do not overhear a person walking close behind them,” he wrote.) Five species, including C. elephantopus, would eventually go extinct. But the tortoises’ long-term storage convenience had one unexpected benefit.

“If a ship was under siege, sailors would unload it by throwing things overboard,” said Garrick. “The first thing to go was stuff stored in the hull. Tortoises don’t swim, but they float like wine corks, and it so happens that the prevailing current runs northeast through the islands. The last place a tortoise might catch land before being swept into the ocean was the northern part of Isabela island. This is where they would have washed up.”

Three years ago, Garrick and Colleagues sequenced the genomes of museum specimens of C. elephantopus and Chelonoidis becki, a closely related tortoise found on the northern part of Isabela island. They found C. elephantopus genes in a few C. becki, suggesting that some castaway tortoises historically made landfall and mated with the locals.

For the new study, the researchers traveled to Isabela island. On the island’s northern tip, on the slopes of Volcano Wolf, they took genetic samples from 1,600 C. becki individuals. Of these, 84 contained so much C. elephantopus DNA that at least one recent ancestor must have been a purebred C. elephantopus.

None of the purebreds was spotted, but because of the genetic signals’ strength and the hybrids’ youth — many were juveniles — the researchers estimate that about 40 purebreds still survive. Given that individual tortoises from other giant Galapagos species have lived for 170 years in captivity, some of the survivors could conceivably have been thrown from ships themselves.

Later this year the researchers will return to Isabela, where they hope to establish a captive breeding program using hybrids and, if they can find them, a few true C. elephantopus. The tortoises could roam again, their slaughter an evolutionary chapter rather than an end.

“The way they were moved around creates a rare opportunity to resuscitate a species that we thought we’d lost,” said Garrick.

Citation: “Genetic rediscovery of an ‘extinct’ Galápagos giant tortoise species.” By Ryan C. Garrick, Edgar Benavides, Michael A. Russello, James P. Gibbs, Nikos Poulakakis, Kirstin B. Dion, Chaz Hyseni, Brittney Kajdacsi, Lady Márquez, Sarah Bahan, Claudio Ciofi, Washington Tapia, and Adalgisa Caccone. Current Biology, January 9, 2012.

Skateboard wheel art - the Darwin series

My friend Jim F (of Don Ernesto fame : http://dernesto.tumblr.com/) sent me these super cool skateboard wheels he had comissioned before he moved to the field

You can find out more about them here (and scroll down, there are also T shirts!)

Darwin’s Struggle: The Evolution of the Origin of Species

From Top documentary films

Documentary telling the little-known story of how Darwin came to write his great masterpiece, On the Origin of Species, a book which explains the wonderful variety of the natural world as emerging out of death and the struggle of life.

In the twenty years he took to develop a brilliant idea into a revolutionary book, Darwin went through a personal struggle every bit as turbulent as that of the natural world he observed.

Fortunately, he left us an extraordinary record of his brilliant insights, observations of nature, and touching expressions of love and affection for those around him.

He also wrote frank accounts of family tragedies, physical illnesses and moments of self-doubt, as he labored towards publication of the book that would change the way we see the world.

The story is told with the benefit of Darwin’s secret notes and correspondence, enhanced by natural history filming, powerful imagery from the time and contributions from leading contemporary biographers and scientists.

CLICK HERE TO WATCH FREE ONLINE

Epigenetics: How Evolution Is Evolving

For me, epigenetics has to be one of the most exciting developments in genetics recently, its elegant and complex, its an amazing reminder of how our own actions will effect others in the future (an excellent metaphor) and also how often scientists will all too quickly dismiss (and sadly, mock) a theory (in this case Lamarckism) only to revist the ideas a century later and find truth and value in some aspects of the original work...-MA

from the National Geographic blog
By ANDREW HOWLEY

Ever since the 1940s, the "modern synthesis" has presented evolution as the result of random mutations to DNA creating altered versions of living creatures that live and reproduce or die childless based on how well they happen to fit into their environment. This idea has served well in many ways for the generations since then, but now there's a new kid in town.

Meet the "New" Kid
"Epigenetics" addresses the increasing evidence that things other than DNA can control the appearance and function of living things, can be passed on to future generations, and most importantly, can arise in direct response to external environmental conditions. It's been covered in Science and TIME, on NOVA, Science Daily, and in an exposé-like series of articles from Scoop.co.nz.

This means that scientists should make room in the pantheon next to Darwin for the often ridiculed "stretch-your-neck-to-become-a-giraffe" Lamarck, who proposed that organisms change throughout their lives and pass on acquired traits to their offspring.

A closer look at history shows we also need to make a little more room next to Darwin for... Darwin himself.

The modern synthesis included certain of Darwin's theories, but discarded others, including that of "pangenesis," his idea that each body part somehow contributes "gemmules" of information to the sex cells to pass on traits acquired through use or disuse in the parent's life.

Tiny Prions, Major Changes
Recent work is showing that Darwin was more correct than he's been given credit for. In "Epigenetics in the Extreme" from the October 29 Science magazine special issue on epigenetics, Randal Halfmann and Susan Lindquist discuss protein molecules called prions, which turn out to be remarkably similar to his hypothetical gemmules.

The magic happens when prions interact with the rest of the cell.

Prions are found inside cells and can take on different shapes, based on environmental conditions such as temperature or the presence of certain chemicals. Once altered, these proteins can bump into other prions and cause them to take on the new shape as well. When the cell divides, both daughter cells will contain prions of both states, and the chain reaction can keep occurring in that new generation.

The magic happens when prions interact with the rest of the cell, and even with DNA itself. The different shapes can cause different proteins to be made, or different parts of the DNA to be read or ignored, which can then trigger different actions or developments in the cell or the whole organism. If the external conditions change though, the other form of the prion will take precedence, and once again perform the original function.

Some may actually become incorporated into the DNA.

Halfmann and Lindquist even state that "these traits can ultimately become hardwired by subsequent genetic changes," meaning some prion alterations may actually become incorporated into the DNA, thus blurring the line between genetics and epigenetics and raising intriguing chicken-and-egg type questions.

Whale-Size Implications
The broader implication of prions on epigenetic inheritance and evolution in general is that the ability to form different structures or perform different functions can be selected for at one time, and then kept around though unexpressed for generations, just waiting for the appropriate environmental trigger to reappear. When it is next expressed, other changes to the species may cause the original effect to take on slightly new forms, thus the organism responds to the environment with an existing toolkit, but continues to take on new appearances.

As a purely hypothetical example, the appearance of webbed fin-like appendages in birds or mammals in aquatic environments could thus be a result of the ancient fish-fin programming being kicked into a new usage as a result of a return to an ancestral environment.

Evidence of epigenetic adaptation and inheritance opens up many new doors of speculation about evolution. In early whales for example, could the particular effects of limb use for paddling, or simply living in a more buoyant environment have had epigenetic influences on the cells of adults or developing offspring? (

Time for a More Modern Synthesis?

The overriding significance of these discoveries is that we now see concrete illustrations of how living things actively adapt to their environment even at a cellular level and can in at least some cases pass on those adaptations to their offspring. While theorized by many in the past, this is fairly new ground for modern discussions of evolution.

Prevailing view now clearly too narrow
The prevailing view that variation in a species is simply the result of a DNA program locked off from the world and altered only through random errors in transcription is now clearly too narrow. The study of epigenetics shows us that life and evolution are dynamic processes, based on the complex back-and-forth relationships between organisms and their entire environment.

And a Hint of Mind-Blowing Context
Finally, while these experiments and observations have been made mostly with single-celled organisms like yeast, or simpler animals like fruit flies, it's important to remember that even the most advanced organisms are still made up of individual cells. Most remarkably, you yourself started out life as a single-celled organism, developing in an environment rich in chemical inputs and signals being produced by your mother in ever-changing response to her environment.

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References
Halfmann R and Lindquist S (2010) Epigenetics in the Extreme: Prions and the Inheritance of Environmentally Acquired Traits. Science 330 (6004): 629 - 632 DOI: 10.1126/science.1191081

ABSTRACT
Prions are an unusual form of epigenetics: Their stable inheritance and complex phenotypes come about through protein folding rather than nucleic acid–associated changes. With intimate ties to protein homeostasis and a remarkable sensitivity to stress, prions are a robust mechanism that links environmental extremes with the acquisition and inheritance of new traits.

My name is DarWIN Not DarLOSE

Dana Carvey is "DARWIN" - watch more funny videos

Thanks to Cleve H. for the link

Creation trailer

Darwin coming to the big screen in "Creation"

image from "Beware the Believers"

From Iwatchstuff.com
Real-life couple Paul Bettany and Jennifer Connelly will be playing Charles and Emma Darwin in Creation, a biopic based on the book Annie's Box. From THR:

Bettany will play the British father of evolutionary theory, and Connelly will play his wife, Emma, in the big-screen take on the life of the controversial "On the Origin of Species" author.
Amiel's film portrays Darwin as a man torn between his love for his deeply religious wife and his own growing belief in a world where God has no place. The scientist finds himself caught in a struggle between faith and reason, love and truth.

This film is going to be so adorable with these two--like looking at a gossip magazine, but with Bettany wearing a giant beard. They should have a baby or two to promote it.