Our Tangled Family Tree

Consider Homo naledi.  A humanoid species whose remains were found several years ago in a cave in South Africa, it had a smaller brain than our direct ancestors, walked upright, and may have used tools.  And, scientists now believe, it lived between 236,000 and 335,000 years ago — which means it would have been alive and kicking when early humans were, too.

mm8345_20150306_134-3The dating of the remains of Homo naledi suggests that the family tree of human beings is a lot more tangled than people once thought.  As scientists focus more and more on searching for fossil evidence of human-like species, they are uncovering new information that reveals a number of different species romping around the pre-historic world.  The Smithsonian page on human ancestry now shows more than 15 early human species.  With so many variations of humanoids, there are bound to be evolutionary dead ends — and, the more human-like remains that are found, the more likely it is that the different offshoots of the evolutionary tree overlapped in time and may have interacted.

Scientists already believe that, around 300,000 or so years ago — or about the same time as the dates suggested for Homo naledi — there were three different offshoots of one of the root humanoid ancestors, Homo heidelbergensis.  Humans remained in Africa, Neanderthals ventured from Africa into Europe, and Denisovans moved east, into Asia.  We know that, for many years thereafter, there was physical interaction between human ancestors and Neanderthals, because many modern humans have a small percentage of Neanderthal DNA.  With three groups of humanoids around, it’s not much of a stretch to imagine Homo naledi existing in that same time frame.   And who knows whether scientists will unearth evidence of other distinct, humanoid species that also date from that same time period?

The intriguing question is:  what happened to those other species?  Did the human ancestors simply prove to be superior in brainpower, body design, tool-making ability, and other attributes that gave them an evolutionary advantage and allowed them to simply out-compete the other species for food, living space, and other conditions that made humans more successful in reproducing . . . or did the early humans slaughter those who were different and drive them into extinction?  Maybe there is a reason that the remains of Homo naledi were found in a cave — they were desperately hiding from our ancestors.

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Learning From The Strangest Creatures On Earth

Tardigrades are extremely weird, extremely small creatures — but it looks like they’ve got a lot to teach us.

tardigrade_imagelargeTardigrades are eight-legged microscopic creatures that were first discovered about 450 years ago.  They are undeniably ancient, having diverged from precursor animal species more than 600 million years ago.  That makes them one of the oldest species on Earth.  In close-up photos, they look like manufactured animals . . . or perhaps characters in a video game.  They’re also called water bears, and some people curiously describe them as “adorable.”

But here’s the most interesting part:  tardigrades are the ultimate survivors.  In fact, they might be the hardiest species in the world.  Recently, scientists successfully revived a tardigrade that had been frozen solid for more than 30 years — that’s since the Reagan Administration, in case you’re counting — and the species also can withstand dehydration and a total vacuum.  Of particular interest to scientists, tardigrades also can survive radiation levels that are lethal to most organisms.

Scientists studying one of the toughest tardigrades learned that the little guys have a special protein that provides protection against radiation.  Dubbed “damage suppression” or “Dsup” by researchers, the protein envelops tardigrade DNA and protects it from radiation injury while allowing it to maintain all of its normal functions.  Even more intriguing, scientists think “Dsup” could be developed in human beings, and provide protection for humans engaged in space travel or that need extreme radiation therapy.  It may be that, in the future, humans are thanking our little water bear friends for providing us with a method that allows us to safely explore the far reaches of our solar system and the galaxy beyond.

Well . . . maybe they are kind of cute and cuddly after all.

Where Do Dogs Come From?

The New York Times recently published a fascinating article on ongoing research into the origin of dogs.  By collecting and analyzing the DNA of current dogs and the remains of their long-dead forefathers, scientists are hoping to determine when man’s best friend first appeared on the scene, and where.

When people have thought about the origin of dogs at all, they’ve assumed that dogs are simply domesticated wolves, first developed long ago when hunters shared food with wolves and trained them to become reliant on, and loyal to, humans.  Scientists now believe that’s probably not what happened.  They note that, although dogs and wolves are so closely related they can interbreed, there are important differences in their physiology and especially their behavior.  Some scientists now hypothesize that dogs were, in effect, self-selected, and some variation of ancient wolf began to follow tribes of early human hunter-gatherers because scraps of food were readily available, and became tamer and tamer in their interactions with humans because the friendlier wolves were much more successful in getting food and breeding — which is the ultimate key to evolution.

IMG_0548But where did the domestication process happen, and when?  Most scientists believe it happened 15,000 years ago, and the process was so rapid that by 14,000 years ago people were burying dogs, sometimes along with humans.  Others believe that dogs are much older and that the domestication may have occurred as long as 30,000 years ago.  As for where dogs first developed, the candidates range from Europe to Africa to Siberia.  To try to answer some of the questions, scientists are collaborating on a vast world-wide DNA collection process and are hoping that, if they assemble enough data, they may be able to trace origins and find useful clues to answer these questions.

They are important questions, and not just for the dog lovers among us.  (In fact, one of the scientists involved in the project, far from being a warm and fuzzy dog fan, contends that the modern house dog “may have evolved into a parasite.”)  The period of human evolution from 30,000 to 15,000 years ago is shrouded in mystery, but clearly something was happening as humans progressed from roving bands of hunter-gatherers to multi-family tribes that formed settlements, built permanent structures, grew crops, and eventually created the first cities and organized civilizations.  It is not far-fetched to speculate that the training and domestication of dogs, and their assumption of their familiar roles of protector, fellow hunter, and treasured friend, may have been an important part of that settling down process.  Those of us who have and love dogs certainly can attest that there is a strong bond between humans and canines and that, in many respects, the bond makes dog owners better people.

Where did Kasey, and Penny, and Dusty and George before them, come from, and how did their distant ancestors affect the development of human culture?  I’d like to know.

Testing For Jack The Ripper

“Jack The Ripper” is arguably the most famous criminal — and certainly the most famous uncaught criminal — in world history.  The Ripper was a bloody serial killer who slit the throats and then horribly mutilated the bodies of prostitutes in the foggy Whitechapel district of London in the late 1800s.  His brutal murders were prominently reported in lurid detail in the London press of the day and terrified people throughout the world.

Now an amateur sleuth has published a book that contends that DNA evidence reveals that Jack the Ripper was a Polish immigrant barber named Aaron Kosminski, and a number of news organizations are reporting those findings as fact.  Should they?

Not so fast.  How do you use DNA evidence to conclusively prove who committed terrible murders more than 100 years ago — decades before DNA was even identified by Watson and Crick, much less before DNA tests were developed and DNA samples collected?  In this case, the conclusions are based on a single scarf that purportedly is linked to one of the Ripper’s victims named Catherine Eddowes.  The DNA test showed that bloodstains on the scarf were linked to distant relatives of Eddowes, while another DNA signature from another substance on the scarf is linked to the distant relatives of Kosminski.

But there are obvious problems.  Some people question whether the scarf really has any connection to Eddowes, and in any case it hasn’t been held in scientific isolation all these years; instead, it’s been subject to potential contamination.  And an even bigger problem is that the kind of DNA recovered from the scarf is not nuclear DNA, which scientists believe is unique to one human being, but rather mitochondrial DNA, which is passed down from mothers to children and can be shared by large groups of people.  The mitochondrial DNA linked to Kosminski is a common subtype — which means that the finger doesn’t point just at Kosminski.

For all of these reasons, Ripperologists are skeptical of this latest claim to have solved some of history’s greatest unsolved crimes.  Was Aaron Kosminski in fact the brutal Jack the Ripper?  I think we’ll never know.

My Kingdom For A Hearse!

William Shakespeare’s gravestone states, in part:  “Blessed be the man that spares these stones,  And cursed be he that moves my bones.”  Now the historical figure behind one of Shakespeare’s most famous literary creations — Richard III — might well share that sentiment.

Scientists in Great Britain launched a careful search for the remains of Richard III, and they are convinced they found them — buried beneath an ordinary parking lot.  King Richard III reined for only two years and was killed in the Battle of Bosworth Field, where Shakespeare’s Richard III famously cried:  “A horse!  A horse!  My kingdom for a horse!”  The dead king’s body was taken to Leicester, England, where it was buried in a church called Greyfriars.  But the church was demolished during the Reformation in the 16th century, and its exact location was lost in the mists of time.  Historians later determined the location of the church, which is now occupied by a parking lot.  They unearthed remains that had been buried in a hurriedly prepared, too small grave, compared the DNA of the remains to the DNA of a seventeenth-generation descendant of Richard III’s sister, and confirmed from the DNA match that the remains were indeed those of the former king.

The remains show that Richard III was not hunchbacked — as he is often depicted — but rather was the victim of scoliosis, a condition that causes a marked curvature of the spine.  The remains also show that Richard III was treated very rudely at the Battle of Bosworth Field.  His skull was pierced by a sharp blade, another part of it was cut away, and it bore the evidence of six other injuries to the face and head.  The rest of his skeleton revealed two injuries, including marks on the pelvis that suggests that the king may have taken a spear up the keister from one of the victors on the battlefield.  No wonder he wanted a horse!

I’ve always thought that Richard III was one of Shakespeare’s greatest plays, and that the Richard III he created was one of his most memorable characters.  (If you’re interested in the play but far away from Stratford-upon-Avon, the 1995 film of Richard III, starring Ian McKellen as a Richard transplanted into a modern fascist world, is excellent.)  The identification of the remains of the king — which now will be more appropriately interred — just add another interesting chapter to the tale of a fascinating historical figure.

The Genetic Snare

Recently a friend survived a heart attack.  He didn’t smoke, kept his weight down, ate the right things, and got exercise.  But his father had had a heart attack, and when my friend reached his mid-50s, so did he.

When something like that happens to a person you know, it shakes you.  You think about your own family medical history and wonder how many of those health problems were due to lifestyle and how many to awesome genetic forces lurking deep within our cells, like tiny time bombs that could explode with devastating consequences at any moment, irrespective of how much lettuce you eat?  Did my father, uncle, and grandfather die of cancer because they were heavy smokers, or because of some squamous anomaly in their mitochondria that was triggered by strands of DNA without regard to intake of tar and nicotine?

And, probing even deeper into the levels of introspection, what would you prefer the answers to these questions to be?  Are you a fatalist who is more comfortable thinking you’ve already been dealt all the cards and just have to play the hand as well as you can?  If you could take a test and determine, conclusively, that the raging fires of cancer were going to consume your body no matter what you did, would you want to know so you could adjust your lifestyle accordingly and move down the spectrum to enjoy the delightful but unhealthy things you’ve avoided?  Or would you rather hope that your good behavior and healthy lifestyle could win you a reprieve from the otherwise inevitable genetic snare?

I’m in the latter category.  I’d like to think that my decisions make a difference to the equation and might have an impact on whether I keel over in the near future.  My friend’s situation makes me think, however:  “Am I just kidding myself?”

Mona Ghoulish

Obviously, some people wonder about who Mona Lisa really was — but is it really worth digging up the remains of some woman who has been buried for centuries in the potentially forlorn hope that you can figure it out?

Italian authorities apparently have answered that question in the affirmative.  An art historian named Silvano Vinceti thinks that the model for Mona Lisa was a woman named Lisa Gherardini who died in 1542 and is buried in a convent in Florence.  He is going to start excavating at the convent Saint Orsola, searching for Ms. Gherardini’s bones.  When he finds her skull, he hopes to extract DNA that will allow him to “rebuild her face” using “scientific techniques.”  There is some skepticism that the results of the effort will be conclusive.  (No kidding!)

I’m all for science, but doesn’t anybody else think this effort is disturbing and ghoulish?  Ms. Gherardini was laid to rest more than 550 years ago.  Why should her bones be disturbed and used in some dubious science experiment in an effort to satisfy the idle curiosity of the art historians who want to know the subject of the world’s most famous painting?  Have we lost all notions of respect for the dignity of the dead?  And isn’t part of the allure of the Mona Lisa its enigmatic quality, anyway?