Meleagris gallopavo (Wild turkey)
We hardly knew ye.
In autumn 2006 a team of researchers went on an expedition to Iceland, where they discovered something that made the headlines across the world. The discovery even made it into the Guinness Book of World Records.
One of the Arctica islandica bivalve molluscs, also known as ocean quahogs, that the researchers picked up from the Icelandic seabed turned out to be around 405 years old, and thus the world’s oldest animal.
However, after taking a closer look at the old mollusc using more refined methods, the researchers found that the animal is actually 100 years older than they thought. The new estimate says that the mollusc is actually 507 years old.
The mollusc’s 507-year-long life came to an abrupt end in 2006 when the British researchers – unaware of the animal’s impressive age – opened up its shell to put it under scientific scrutiny.
Image: Bangor University
A new study from Cornell shows that complex molecules that could potentially aid in the rise of cells can be built from reactions embedded deep in clay:
“We propose that in early geological history clay hydrogel provided a confinement function for biomolecules and biochemical reactions,” said Dan Luo, professor of biological and environmental engineering and a member of the Kavli Institute at Cornell for Nanoscale Science.
In simulated ancient seawater, clay forms a hydrogel — a mass of microscopic spaces capable of soaking up liquids like a sponge. Over billions of years, chemicals confined in those spaces could have carried out the complex reactions that formed proteins, DNA and eventually all the machinery that makes a living cell work. Clay hydrogels could have confined and protected those chemical processes until the membrane that surrounds living cells developed.
The trouble is that reports like this are becoming all too common. I don’t think a week goes by that there’s not a new report of interesting compounds arising in the deep sea, in hydrothermal vents, in ice, on volcanoes, under lightning strikes, in tidal pools, on comets, on Mars…
But if ostensibly life-giving compounds can spring up practically anywhere, that leaves us precisely nowhere on the question of where it actually did so.
It has been the subject of intense study since time immemorial, and is known quite intimately by each of us, and yet the human body is still a mystery in its details. In this day and age, new discoveries about the human body are usually made at the microscopic or the physiological scale, but here’s a genuine new discovery in gross anatomy: a whole new ligament in the human knee that had previously gone unnoticed. Ligaments are bands of fibrous tissue that “tie” bones to other bones. The newly discovered anterolateral ligament was found by Belgian surgeons looking for clues as to why some patients still have particular trouble after ACL repair surgeries—and they started with speculation from 1879 about a yet-unknown ligament.
The discovery is reported in the Journal of Anatomy: Claes, S., Vereecke, E., Maes, M., Victor, J., Verdonk, P. and Bellemans, J. (2013), Anatomy of the anterolateral ligament of the knee. Journal of Anatomy, 223: 321–328. doi: 10.1111/joa.12087
One of the changes that was happening in biology at the time this blog was started was the realization that the importance of the gene had been somewhat overemphasized in the previous decades; in addition to learning more and more about the genome, biologists have also been learning more and more about how the gene needs to be understood in a wider organismal context, and life can’t be simply reduced to the expression of genes.
Here’s a new story from UC Davis that illustrates how extranuclear genes, that is, the DNA found in the cell’s organelles (such as mitochondria), have a disproportionate effect on the cell’s activities relative to their small number.
“The influence of genes outside the nucleus was known to an earlier generation of field ecologists and crop breeders, said Dan Kliebenstein, professor in the UC Davis Department of Plant Sciences and Genome Center and senior author on the paper published Oct. 8 in the online journal eLife. This is the first time that the effect has been quantified with a genomic approach, he said.
Bindu Joseph, a postdoctoral researcher in Kliebenstein’s lab, and Kliebenstein studied how variation in 25,000 nuclear genes and 200 organellar genes affected the levels of thousands of individual chemicals, or metabolites, in leaf tissue from 316 individual Arabidopsis plants.
They found that 80 percent of the metabolites measured were directly affected by variation in the organellar genes — about the same proportion that were affected by variation among the much larger number of nuclear genes. There were also indirect effects, where organellar genes regulated the activity of nuclear genes that in turn affected metabolism.”
Since these genes aren’t transmitted in the ordinary Mendelian fashion through the nucleus, I find it interesting to ask what role these extranuclear genes and their patterns of descent may play in evolutionary processes.
On the other hand, knowledge of these genes also plays a role in current attempts to “treat” mitochondrial genetic diseases through IVF; I say “treat” because, rather than treating a developed individual who already has the disease, the technique actually involves creating embryos from the start without the disease-carrying genes, by replacing the mother’s mitochondria with mitochondria from a third individual, hence the “three-parent” embryos that have been in the news lately. Rebecca Taylor writes more about these techniques here.
” In 2 milliseconds it has bulleted skyward, accelerating at nearly 400 g’s—a rate more than 20 times what a human body can withstand. At top speed the jumper breaks 8 mph—quite a feat considering its body is less than one-tenth of an inch long.
This miniature marvel is an adolescent issus, a kind of planthopper insect and one of the fastest accelerators in the animal kingdom. As a duo of researchers in the U.K. report today in the journal Science, the issus also the first living creature ever discovered to sport a functioning gear. ‘Jumping is one of the most rapid and powerful things an animal can do,’ says Malcolm Burrows, a zoologist at the University of Cambridge and the lead author of the paper, ‘and that leads to all sorts of crazy specializations.’”
The strikingly mechanical nature of the adapatation has found its way into the design debate. I leave this, for the moment, for the reader to ruminate for himself.
We found this tiny fellow sitting on the bricks next to the basement stairwell a few nights ago; a young Hyla versicolor, or Gray Treefrog. Certainly one of the smallest frogs I’ver ever seen in person, although there are tinier species elsewhere. The key, for scale, is just an ordinary sized house key. He was likely attracted to the insects near the light in the stairwell, although this put him in danger of being snapped up by the larger toads in the same area. After the kids got to see him, we let him go safely elsewhere. The treefrog’s call is a familiar sound in the summertime woods around here.
…Life and Man may be, that is.
The first story here is from the University of Oregon, where geologists claim to have identified land-dwelling fossils from 2.2 billion years ago, four times older than the generally accepted date of the first land life. From the university:
A new study, led by geologist Gregory J. Retallack of the University of Oregon, now has presented evidence for life on land that is four times as old — at 2.2 billion years ago and almost half way back to the inception of the planet.
That evidence, which is detailed in the September issue of the journal Precambrian Research, involves fossils the size of match heads and connected into bunches by threads in the surface of an ancient soil from South Africa. They have been named Diskagma buttonii, meaning “disc-shaped fragments of Andy Button,” but it is unsure what the fossils were, the authors say.
“They certainly were not plants or animals, but something rather more simple,” said Retallack, professor of geological sciences and co-director of paleontological collections at the UO’s Museum of Natural and Cultural History. The fossils, he added, most resemble modern soil organisms called Geosiphon, a fungus with a central cavity filled with symbiotic cyanobacteria.
This is not the first time that Retallack has argued for earlier land life, and with its vastly older age the new claim will certainly not be one that is accepted uncritically.
Elsewhere, genetics has revealed something interesting: the discovery of a new Y-chromosome lineage. Y-chromosomes are passed down through male generations, preserved from the sort of mixing that happens to the other chromosomes. They can thus be used to identify clear lineages, much like mitochondrial DNA can be used to establish matrilineal lineages. Geneticists have previously been able to trace the Y-chromosome lineage back to about 200,000 years ago to a hypothetical figure called “Y-chromosome Adam” who would represent the individual from whom all modern humans have inherited their Y-chromosomal DNA (although not the only human living at that time, or the only human to contribute to all modern human DNA.) Now, however, something new has turned up.
The DNA of Albert Perry may change the story of human origins. Perry, an African-American, approached a DNA testing company to find out more about his ancestry. The results would have come as quite a surprise (had he lived to see them), and have raised questions for geneticists around the world.
It turns out that Perry carried a very different type of Y chromosome, never seen before. Every male has a Y chromosome, which is a piece of DNA inherited by sons from their fathers. But, unlike most DNA, the Y chromosome is not shuffled as it is passed down, and changes only slowly through mutation. Tracking these mutations allows scientists to create a genetic tree of fathers and sons going back through time.
As a man may have several sons or none, some branches of the genetic tree die out each generation, while others become more common. Going back through time it is therefore inevitable that all modern Y chromosomes must descend from from one man at some point in the past. He has become known as “Y-chromosomal Adam”.
This Adam was not the first man, or the only man, from his time to contribute to modern human DNA. It is just that, by chance, his Y chromosome was the only one to survive until today.
What is surprising about Perry’s Y chromosome is that it did not descend from Y-chromosomal Adam’s. Or rather that the established “Adam” has lost his title to a new “Adam”, further back in time, where Perry’s branch split from the tree (see figure). While the former-Adam is estimated to have lived around 202,000 years ago, the revised one is thought to be about 338,000 years old.
We’ve had a lot of rain recently, and I found these popping up in my backyard last week. While not quite rare, these “ghost plants” or “Indian pipes” (Monotropa uniflora) are sufficiently uncommon to be a pleasing find. They look like fungi but are in fact plants—plants with no clorophyll. Instead they are a kind of saprophyte, a parasitic, nonphotosynthetic plant that feeds off of a host instead of producing energy directly. In this case, the ghost plants absorb nutrients from fungi that themselves feed on tree roots. Thus the tree produces energy through photosynthesis, which is fed upon by the fungi, which are fed upon in turn by the ghost plants.
One of the more deplorable signs of cultural degeneration is the rise of the so-called “vodka martini.” I am, in this matter, a follower of Judge Bork, who in a famous essay for National Review wrote that “a drink made with vodka is not a martini. A martini means gin.” (I respectfully dissent from Judge Bork’s dismissal of bourbon. Also, pace James Bond, a proper martini is to be stirred, not shaken.)
In any case, the true gin martini, as well as the gin-and-tonic, may soon be threatened by more than vodka, as it seems that a fungus is now attacking the junipers from which gin takes its characteristic flavor. Popular Science reports:
“A fungus-like pathogen, first discovered just five years ago, now is wreaking havoc on juniper trees in the U.K. This is the first time that this mold, called Phytophthora austrocedrae, has ever been seen in Europe. It threatens a tree that’s native to the U.K. and important to ecosystems there. Junipers are known for the berries, which give gin that piney flavor. Most gin companies don’t get their juniper berries from the U.K. nowadays, ABC News reports, but the infection may cross onto mainland Europe.”
I suppose I will just have to stick to my favorite instead: the bourbon Old Fashioned.