Posts tagged DNA
Asian migrants stuck on land bridge for milleniums
Feb 27th
likely a long-term refuge for early Americans
A new study led by the University of Colorado Boulder bolsters the theory that the first Americans, who are believed to have come over from northeast Asia during the last ice age, may have been isolated on the Bering Land Bridge for thousands of years before spreading throughout the Americas.
The theory, now known as the “Beringia Standstill,” was first proposed in 1997 by two Latin American geneticists and refined in 2007 by a team led by the University of Tartu in Estonia that sampled mitrochondrial DNA from more than 600 Native Americans. The researchers found that mutations in the DNA indicated a group of their direct ancestors from Siberia was likely isolated for at least several thousand years in the region of the Bering Land Bridge, the now-submerged plain that lies between northeast Asia and Alaska once exposed by a significantly lower sea level.
CU-Boulder researcher John Hoffecker, lead author of a short paper article appearing in the Feb. 28 issue of Science magazine, said the Beringia Standstill model gained little traction outside of the genetics community after it was proposed and has been seen by some scientists outside of the field as far-fetched. But the new paper by Hoffecker and co-authors Scott Elias of Royal Holloway, University of London, and Dennis O’Rourke of the University of Utah adds credence to the Beringia Standstill idea by further linking the genetics to the paleoecological evidence.
“A number of supporting pieces have fallen in place during the last decade, including new evidence that central Beringia supported a shrub tundra region with some trees during the last glacial maximum and was characterized by surprisingly mild temperatures, given the high latitude,” said Hoffecker of CU-Boulder’s Institute of Arctic and Alpine Research. The last glacial maximum peaked roughly 21,000 years ago and was marked by the growth of vast ice sheets in North America and Europe.
While a debate rages on about when early humans first migrated into the New World, many archaeologists now believe it was sometime around 15,000 years ago after retreating glaciers opened access to coastal and interior routes into North America.
The relatively mild summer climate in Beringia at the time was caused by North Pacific circulation patterns that brought moist and relatively warm air to the region during the last glacial maximum. Geologists believe the Beringia gateway between Siberia and Alaska was more than 600 miles wide at the time.
Hoffecker and others are now theorizing that a population of hundreds or thousands of people parked itself in central Beringia for 5,000 years or more. One key to the extended occupation may have been the presence of wood in some places to use as a fuel to supplement bone, which burns hot and fast. Experiments have shown that at least some wood is necessary to make bone practical as a fuel.
Elias, a paleoecologist and also an INSTAAR affiliate, said research using fossil pollen, plant and insect material from sediment cores from the now submerged landscape show that the Bering Land Bridge tundra environment contained enough woody plants and trees like birch, willow and alder to provide a supplement to bone.
Work by Elias and others included the analysis of certain beetle species that live in very specific temperature zones, allowing them to be used as tiny thermometers. The insects indicated that temperatures there were relatively mild during last glacial maximum that ran from about 27,000 years to 20,000 years ago, only slightly cooler than temperatures in the region today.
“The climate on the land bridge and adjacent parts of Siberia and Alaska was a bit wetter than the interior regions like central Alaska and the Yukon, but not a lot warmer,” said Elias. “Our data show that woody shrubs were available on the land bridge, which would have facilitated the making of fires by the people there.”
Evidence from the 2007 study indicated a set of genetic mutations in mitochondrial DNA, which is passed down from mother to offspring, clearly accumulated after the divergence of people from their Asian parent groups in Siberia but before their dispersal throughout the Western Hemisphere, said O’Rourke. In addition, ancient DNA from human skeletal remains found at a 24,000-year-old archaeological site in southern Siberia also appears consistent with the divergence of Native American groups from their Asian forbearers by that time window, he said.
“The genetic record has been very clear for several years that the Native American genome must have arisen in an isolated population at least by 25,000 years ago, and the bulk of the migrants to the Americas really didn’t arrive south of the ice sheets until nearly 15,000 years ago,” O’Rourke said. “The paleoecological data, which I think most geneticists have not been familiar with, indicate that Beringia was not a uniform environment, and there was a shrub tundra region, or refugium, that likely provided habitats conducive to continuous human habitation.”
“From my view the genetics and paleoecology data come together nicely,” said Hoffecker, who co-authored a 2007 book with Elias titled “The Human Ecology of Beringia.” While the weakest link to the Out of Beringia theory is the lack of archaeological evidence, Hoffecker believes future research on now submerged parts of Beringia as well as lowlands in western Alaska and eastern Siberia that still remain above water may hold clues to ancient habitation by Beringia residents, who eventually moved on to be the first group to inhabit the Americas.
Hoffecker also believes that the Beringia inhabitants during the last glacial maximum could have made successful hunting forays into the uninhabited steppe-tundra region to both the east and west, where drier conditions and more grass supported a plentiful array of large grazing animals, including steppe bison, horse and mammoth.
There is now solid evidence for humans in Beringia before the last glacial maximum, as geneticists first predicted in 1997, said Hoffecker. After the maximum, there are two sets of archaeological remains dating to less than 15,000 years ago. “One represents a late migration from Asia into Alaska at that time,” he said. “The other has no obvious source outside Beringia and may represent the people who are thought to have sheltered on the land bridge during the glacial maximum.
“If we are looking for a place to put all of these people during the last glacial maximum, Beringia may be the only realistic option,” said Hoffecker.
A video news story on the research is available at http://www.colorado.edu/news.
-CU-
Indictments: Parents aided in JonBenet’s death
Oct 25th
Grand Jury and Boulder Police say John and Patsy Ramsey murdered their kid. Straight Up
Court documents released Friday show that a Colorado grand jury voted in 1999 to indict the parents of murdered 6-year-old JonBenet Ramsey on charges of child abuse resulting in death and being accessories to a crime.
The district attorney decided that year, however, not to file charges against John and Patricia Ramsey, saying there was insufficient evidence. In 2008, a new district attorney said new DNA evidence cleared the parents and their son in the death.
The court documents, which were previously sealed, show how the grand jury sought to charge each parent with two identical counts.
“The grand jury had alleged that Patsy Ramsey and husband John Ramsey “did … permit a child to be unreasonably placed in a situation which posed a threat of injury to the child’s life or health which resulted in the death of JonBenet Ramsey.”
The grand jury also had alleged that each parent “did … render assistance to a person” who “has committed and was suspected of the crime of murder in the first degree and child abuse resulting in death.”
The documents provide no further details on who that “person” was. The grand jury had accused the couple of committing the offenses “on or between December 25 and December 26, 1996.” JonBenet was found murdered in the basement of the family’s Boulder home the day after Christmas 1996.
The Boulder District Attorney claimed in 2008 that new DNA evidence ruled out the Ramsey’s as JonBenet’s murderer. But new DA Stan Garnet gave the case back to police in 2011. He told Boulder Channel 1s Jann Scott in May that the Ramsey’s were not exonerated by him and that the case was fully in Boulder Police departments hands.
Boulder Police believe that John and Patsy Ramsey were involved with their childs murder and that there was no intruder. The new DA Stan Garnet seems to believe that too.
by Ron Baird
Jann Scott contributed to this story
some information was gathered from CNN
JonBenet Ramsey’s murder front burner
Oct 24th
One of the most notorious unsolved murders in Boulder, not to mention U.S. history, has recently been moved to the front burner, at least for the time being.
On Dec.26, 1996, six-year-old JonBenet Ramsey was found murdered in an obscure basement room in her family home in the University Hill neighborhood. She had been sexually assaulted, then strangled with a garrote.
Due to the fact that JonBenet was a child beauty-pageant star, the case captured the world’s interest and spawned nearly unprecedented media coverage for several years, never going completely away.
The case began as a suspected kidnapping due to an oddly written ransom note, which demanded $118,000 for her safe return. Late in the day, John Ramsey discovered her body and brought it upstairs to a roomful of shocked police officers and Ramsey family friends.
In the course of the investigation, District Attorney Alex Hunter empaneled a grand jury in 1999 to consider the case. The grand jury handed down indictments of JonBenet’s parents—John and Patsy Ramsey—but the indictments were never reported until the Daily Camera published a story earlier this year quoting members of the grand jury saying it had indicted the couple for child abuse resulting in death.
Hunter was quoted as saying he had declined to prosecute the Ramseys at that time because he didn’t believe he could prove the case “beyond a reasonable doubt.”
Daily Camera reporter Charlie Brennan and a group known as the Reporters Committee for Freedom of the Press filed a lawsuit in Boulder District Court in September, claiming:
“The plaintiffs believe… that the indictment is a criminal justice record that reflects official action by the grand jury, and accordingly that it is subject to mandatory disclosure upon request.” Brennan and the RCFP also argue that the indictment should be made public in the interest of government transparency.
The Boulder DA’s office said unsealing the indictment would be “breach of promise” to the jury, citing the importance of maintaining the integrity of grand jury secrecy.
But last week, Weld County Judge Robert Lowenbach, the judge hearing the lawsuit by Brennan and RCFP, ruled that current Boulder District Attorney Stan Garnett must show why the indictment must remain secret.
Not surprisingly, John Ramsey opposes the move unless the entire Grand Jury records are released.
Whatever the grand jury transcripts might show, in 2008, then District Attorney Mary Lacy declared that new DNA technology proved the Ramseys innocent of any wrongdoing.
The genetic material matches came from a drop of blood found on JonBenet’s underwear early in the investigation. The authorities determined then that the blood was not from a member of the Ramsey family but could not say whether it came from the killer.
In 2006, Lacy’s office announced the arrest of John Karr , after several months of investigation. But Karr’s DNA did not match, and less than two weeks later Lacy announced that he was no longer a suspect.
Hal Haddon and Bryan Morgan, attorneys who represent John Ramsey said in a letter to the Camera: “Public release of the allegations of an un-prosecuted indictment only serves to further defame (John Ramsey) and his late wife Patricia. Mr. Ramsey will have no access to whatever evidence the prosecutors presented to the grand jury and will have no ability to disprove those allegations in a court of law. Nor will the public have any ability to evaluate the propriety of the indictment unless the entire grand jury record is unsealed and opened to public view.”
From the beginning, investigators believed someone in the household was responsible, citing the lack of evidence of a break in, the complex layout of the house, the amount of time it took to write the two, 400 +/-word ransom-demand letters and similarities to Patsy’s hand writing. But a key detective, Lt. John Eller, who was the ranking investigator, would not press the Ramseys to be interrogated separately; insisting that the parents were victims, not suspects.
Under pressure, Patsy finally provided writing samples but a forensic handwriting expert ruled that, while very similar, the writing in the sample did not rise to the legal standard required to determine it was hers.
On Wednesday, the judge ordered the grand jury record to be released.
BC1 Editor Ron Baird covered the JonBenet Ramsey investigation for the Colorado Daily, when it was a real newspaper.
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