Newsletter #7
Roots of Human Family Tree Shallower Than Previously Believed
Santa Fe New Mexican/Associated Press
July 1, 2006
By Matt Crenson
Humphrey Bogart
Brooke Shields is probably a descendant of Lucrezia Borgia. Humphrey Bogart is probably a descendant of the prophet Muhammad. And so it goes. Geneticists used to believe that "everybody on earth descends from somebody who was around as recently as the reign of Tutankhamen," according to an article titled "Brotherhood of Man." But revised thinking on their part puts the most remote common ancestor(MRCA)in a much more modern timeframe, so that nearly everyone alive can claim Charlemagne and Ghengis Khan as an ancestor, if statistics and random mating hold true.
The reason is that many, many lines die out. Those that survive have huge numbers of descendants within a few generations, and all of us have huge numbers of ancestors going back to a small genetic pool about a thousand years ago. So a 13-marker Y-STR match such as those reported in Male DNA Ancestry products from DNA Consulting relates to a relatively recent timeframe, unlike previous theories that a match went back many thousands of years to a common male ancestor.
A Monkey's Uncle
From Nature Alert, 28 June 2006
According to an article titled, "Genetic evidence for complex speciation of humans and chimpanzees," by Nick Patterson et al., humans and chimpanzees may have once interbred. The evolutionary split between humans and chimpanzees is much more recent than was thought, according to a new comparison of the complete genome sequences of the two species. The data show that the split occurred no more than 6.3 million years ago, probably less than 5.4 million years ago. The speciation process appears to have been rather unusual � possibly involving an initial split followed by later hybridization before a final once-and-for-all separation.
DNA Shows Man a Descendant of Genghis Khan
By JILL LAWLESS
The Associated Press
Tuesday, June 6, 2006
LONDON -- Tom Robinson had long wondered about his family tree. He never suspected its roots might lie in the Mongolian steppe.
The Florida accountant knew that his great, great-grandfather had come to the United States from England -- but beyond that his research drew a blank. So he turned to the burgeoning field of "bioarchaeology," having his DNA tested to see what it revealed about his origins.
Genghis Khan
He was in for a surprise. According to a British geneticist who pioneered the research, Robinson appears to be a direct descendant of Genghis Khan, the Mongol warrior who conquered vast tracts of Asia and Europe in the 13th century. Read more.
Genetics and Psychiatry
Mood disorders (for instance, depression) and schizophrenia have traditionally been approached as unrelated extremes or opposites on a continuum of psychiatric disorders. But now it seems the genes causing them, and the linkage disequilibrium associated with them, extend from one end of the spectrum to the other. In a report by Nick Craddock and Liz Forty in the European Journal of Human Genetics (2006) 14, 660�668, the gene for bipolar disorder has been shown to also be implemented in other disorders, while manifestation depends more than previously believed on the interaction between one's environment and genetic susceptibility. The title: "Genetics of affective (mood) disorders." This entire issue is devoted to genetics and behavioral psychology/psychiatric medicine.
Oprah a Zulu?
From The Guardian (London), February 17, 2006
G2: New roots: Wealthy African-Americans are using DNA kits to trace their roots - all the way back to Africa
By GARY YONGE
Oprah is a Zulu. Never mind that she was born and raised in Mississippi and her great grandparents hailed from no further away than Georgia and North Carolina, Ms. Winfrey, the queen of the televised confessional, is not just suggesting her lineage might stretch back thousands of years to a specific African tribe. She is asserting it as a definitive fact.
"I always wondered what it would be like if it turned out I am a South African. I feel so at home here . . . Do you know that I actually am one?" she told an audience of 3,200 in Johannesburg last year. "I went in search of my roots and had my DNA tested, and I am a Zulu."
This month in the US, Oprah has been joined by eight other African-American luminaries, including Quincy Jones and Whoopi Goldberg, in tracing their genealogy.
In reality, however, the truths this science reveals are no less selective than those you will hear from a politician.
Science can only tell you so much. Stop the genealogical wheel at an inconvenient moment and some of the world's greatest black icons could be rendered not African, but European. Muhammad Ali's great grandfather was Irish; Bob Marley's father was British.
DNA Doesn't Lie, But People May
According to most historical accounts, the Zulu nation was consolidated only after the departure of slaves from West Africa to the Americas. Moreover, there is little in the way of genetic lineage that comes close to matching a particular linguistic group such as the Zulu nation.
When Oprah had her DNA tested for the programme, the results suggested her most likely match was from the Kpelles tribe of Liberia. Indeed she was told that she could not have come from South Africa. None of this is likely to stop her claiming the Zulus as her kith and kin. "I'm crazy about the South African accent," she said. "I wish I had been born here."
Neanderthal DNA Sequenced More Fully
By Rex Dalton
From Nature vol. 441 no. 7091 p. 260ff. (April 2006)
After the mitochondrial DNA was reconstructed by German scientists about 10 years ago, Neanderthal DNA now yields to a more complete genome foray. Genetic material was sequenced from a 45,000-year-old male.
Genes Implicated
In Cancer, Human Fitness
Reported in Breakthrough
The DNA sequence and biological annotation of human chromosome 1
By S. G. Gregory et al.
From Nature 441, 315-321 (18 May 2006)
ABSTRACT:
The reference sequence for each human chromosome provides the framework for understanding genome function, variation and evolution. Here we report the finished sequence and biological annotation of human chromosome 1. Chromosome 1 is gene-dense, with 3,141 genes and 991 pseudogenes, and many coding sequences overlap. Rearrangements and mutations of chromosome 1 are prevalent in cancer and many other diseases. Patterns of sequence variation reveal signals of recent selection in specific genes that may contribute to human fitness, and also in regions where no function is evident. Fine-scale recombination occurs in hotspots of varying intensity along the sequence, and is enriched near genes. These and other studies of human biology and disease encoded within chromosome 1 are made possible with the highly accurate annotated sequence, as part of the completed set of chromosome sequences that comprise the reference human genome.
Surname Studies
and Y-Chromosome Matches
Validate Each Other
Y-chromosomal STR haplotype analysis reveals surname-associated strata in the East-German population
By Uta-Dorothee Immel et al.
European Journal of Human Genetics (2006) 14, 577�582.
In one of the first large scale studies of its kind, a team of German geneticists concludes that the structure of populations as revealed in Y-STR haplotype clusters corresponds to surname groupings by country of origin. Both means of analyzing a population point to a relatively recent historical timeframe -- as has long been assumed by DNA Consulting and other testing companies.
COMPLETE ABSTRACT:
In human populations, the correct historical interpretation of a genetic structure is often hampered by an almost inherent inability to differentiate between ancient and more recent influences upon extant gene pools. One method to trace recent population movements is the analysis of surnames, which, at least in Central Europe, can be thought of as traits 'linked' to the Y chromosome. Illegitimacy, extramarital birth and changes of surnames may have substantially obscured this linkage. In order to assess the actual extent of correlation between surnames and Y-chromosomal haplotypes in Central Europe, we typed Y-chromosomal short tandem repeat markers in 419 German males from Halle. These individuals were subdivided into three groups according to the origin of their respective surname, namely German (G), Slavic (S) or 'Mixed' (M). The distribution of the haplotypes was compared by Analysis of Molecular Variance. While the M group was indistinguishable from group G (PhiST=-0.0008, P>0.5), a highly significant difference (PhiST=0.0277, P<0.001) was observed between the S group and the combined G+M group. This surprisingly strong differentiation is comparable to that of European populations of much larger geographic and linguistic difference. In view of the major migration from Slavic countries into Germany in the 19th century, it appears likely that the observed concurrence of Slavic surnames and Y chromosomes is of a recent rather than an early origin. Our results suggest that surnames may provide a simple means to stratify, and thereby to render more efficient, Y-chromosomal analyses of Central Europeans that target more ancient events.
Letter to Newsweek Editor about Jewish Diseases
You write that "Ashkenazic Jews have an unusually high risk of certain cancers, as well as Gaucher and Tay-Sachs diseases. Men and women who inherit the mutation that causes Tay-Sachs are unaffected, but if they mate, they have a one-in-four chance of having an afflicted child. That's why Jewish parents-to-be are offered a panel of genetic tests before conceiving."
In fact, traditional Judaism prohibits abortion, yet encourages having children. Thus, genetic testing after marriage, before conceiving, would be futile in the Orthodox community, where genetic tests are administered prior to marriage and to becoming "parents-to-be."
In fact, there is a fairly sophisticated network in place that ensures that no one marries a partner with whom testable genetic defects will manifest. It is a great example of using technology for compassion and to support religious values.
Elisheva Rubin, Cleveland, Ohio
Calling All Heirs
From The Press (Christchurch, New Zealand),March 25, 2006
By JO McKENZIE-McLEAN & BENJAMIN SLADE
An eccentric British millionaire from the landed gentry is casting his eye to New Zealand for an heir.
Sir Benjamin Slade, 59, who is childless, is hunting for a successor to his ancestral $13 million estate in Somerset, including Maunsel House -- a 13th century manor.
None of Slade's army of relatives in England was willing to take on the estate when he died, so he was searching for an heir overseas.
Slade believed that some of his lineage travelled to New Zealand in the distant past.
Genealogists had been employed to hunt Slades down and would be using DNA technology to prove the bloodline.
Wild, Wooly World of DNA
May Create, As Well As Solve, Problems
Abstracted from The New York Times, April 13, 2006
The first in a series of articles in the New York Times, titled "The DNA Age" presents case histories of people whose DNA tests are turning out to be mixed blessings, arousing more expectations than may be justified. From the adopted twins who are looking for financial aid after finding out they are part African and part Native American to the man raised a gentile attempting to invoke the law of return to Israel following the revelation his DNA matched Ashkenazi Jews, the series by Amy Harmon apparently intends to explore the two sides of DNA -- the answers it brings, along with the new questions it raises.
On another front, Indian tribes routinely refuse to accept DNA evidence. According to the article, though, this has not deterred prospective new enrollees. "It used to be 'someone said my grandmother was an Indian,' " says Joyce Walker, the enrollment clerk who regularly turns away DNA petitioners for the Mashantucket Pequot tribe, which operates the lucrative Foxwoods Resort Casino in Connecticut. "Now it's 'my DNA says my grandmother was an Indian.'"
The title of the first of the series is "Seeking Ancestry in DNA Ties Uncovered by Tests." One of the featured DNA test takers was a customer of DNA Consulting.
Tracing dad online;
One teenager's detective work has shown that promises of anonymity for sperm donors may now be worthless
By ALISON MOTLUK for New Scientist Magazine (UK)
Nov. 5, 2005
LATE last year, a 15-year-old boy rubbed a swab along the inside of his cheek, popped it into a vial and sent it off to an online genealogy DNA-testing service. But unlike most people who contact the service, he was not interested in sketching the far reaches of his family tree. His mother had conceived using donor sperm and he wanted to track down his genetic father.
The teenager tracked down his father from his Y chromosome. The Y is passed from father to son virtually unchanged, like a surname. So the pattern of gene variants it carries can help identify which paternal line an individual has descended from and can also be linked to a man's surname.
"This is the first time that I know of it being done," says Bryan Sykes, a geneticist at the University of Oxford and chairman of OxfordAncestors.com , a genetic genealogy service. The case raises serious questions about whether past promises of anonymity can be honoured, he says. . . .
According to the article, around 90,000 donor inseminations take place in the U.S. annually, although not all result in pregnancies.
Mitochondrial Disease? Editor's Summary
Nature
30 March 2006
The notion that the evolution of the eukaryotes (single and multicellular organisms with a nucleus) can be summed up by a single 'universal tree' has taken a battering from recent discoveries. It's looking much more complex now, and the nature of the primitive host that first acquired a free-living microbe as a mitochondrion is as big a mystery as ever. What is certain, though, is that mitochondrial mutations can cause human disease. Some researchers go further, and suggest that the hundreds of 'missing' genes that have moved from mitochondria to other parts of the genome may be linked to common diseases such as diabetes and Parkinson's.
News Feature: Mitochondrial disease: Powerhouse of disease
Many of the genes affecting mitochondria � tiny energy suppliers of cells � reside in the cell nucleus. Nick Lane joins the hunt for these sequences that may underpin diseases such as diabetes. Read about in the March 30 issue of Nature.
High Mutation Rates in Human Y Chromosomes
Although much polymorphism in the human genome has been catalogued, and more suspected, a new estimate of the mutation rate is surprisingly high, according to a letter in Nature Genetics of 26 February 2006 by Sjoerd Repping et al.
The team investigated each of 47 branches (male haplogroups) of the world Y chromosomal tree and searched for large-scale variation. They found large-scale mutations combined paradoxically with limited variation and selective constraints.
Internet Encyclopaedias Go Head to Head
Jimmy Wales' Wikipedia comes close to Britannica in terms of the accuracy of its science entries, a Nature investigation finds.
Published in Nature online: 14 December 2005; Updated online: 22 December 2005 ; Updated online: 28 March 2006
By JIM GILES
One of the extraordinary stories of the Internet age is that of Wikipedia, a free online encyclopaedia that anyone can edit. This radical and rapidly growing publication, which includes close to 4 million entries, is now a much-used resource. But it is also controversial: if anyone can edit entries, how do users know if Wikipedia is as accurate as established sources such as Encyclopaedia Britannica?
An expert-led investigation carried out by Nature � the first to use peer review to compare Wikipedia and Britannica's coverage of science � suggests that there are numerous errors in both encyclopaedias, but among 42 entries tested, the difference in accuracy was not particularly great: the average science entry in Wikipedia contained around four inaccuracies; Britannica, about three.
Considering how Wikipedia articles are written, that result might seem surprising. A solar physicist could, for example, work on the entry on the Sun, but would have the same status as a contributor without an academic background. Disputes about content are usually resolved by discussion among users. Read more. . .
UPDATE (28 March 2006): The results reported in this news story and their interpretation have been disputed by Encyclopaedia Britannica. Nature responds to these objections at this link. Seems Nature is right and EB wrong.
Children of Parents with Alzheimer's
Want to Know If They Have the Gene
March 31, 2006
Genetic screening for the apolipoprotein E gene associated with Alzheimer's Disease appears to be beneficial and welcome to nonsymptomatic adult children of people with the disease, according to an article by Kerri Wachter in this month's Adult Psychiatry. Dr. Robert Green made the announcement at an international conference by the Alzheimer's Association.
Dr. Green said he was surprised by the results of his study, which determined that knowledge of having the gene, not having the gene and not wanting to be screened for it made no difference in levels of depression or anxiety.
Revealing such genetic risk information to asymptomatic patients is not usually done, because the gene is only a marker for susceptibility, not for the disease itself. Another reason for not sharing knowledge of the gene's presence is that there is no treatment at present, and it was feared that screening might increase people's anxiety.
Happily, Dr. Green's study showed that people want to know and can seemingly deal with the results of that screening.
DNA Fuels Dynastic Dilemma
By David Cyranoski, Nature 439/7079:892-3
The Japanese imperial succession is in trouble because of the Y chromosome. Will Japan have a queen?
NEWSWEEK COVER STORY: DNA Testing
It is connecting lost cousins and giving families surprising glimpses into their pasts. Now scientists are using it to answer the oldest question of all: where did we come from?
We Are Family: Father Bill Sanchez (back row, right) learned that his genes share characteristics of an ancient Jewish line. Some of his relatives closely match the signature, too.
By CLAUDIA KALB
Newsweek
Feb. 6, 2006 issue - Brian Hamman had always wondered: what was up with his great-grandfather Lester? Hamman, an avid genealogist, could trace his patrilineal line back to 19th-century rural Indiana, but there was a glitch in the family records. Great-Grandpa Lester, the documents showed, was born before his parents were married. So was Lester really a Hamman? Was Brian? Three years ago DNA tests confirmed the lineage and a simple family mystery was solved: Lester's parents had hooked up before they walked down the aisle on July 25, 1898. Lester was indeed a Hamman, and so is Brian. "I'm delighted," he says....
Are You Native American?
Only Your Ear Wax Knows for Sure
It has long been known that one trait Native Americans share is a tendency toward excessive, dry ear wax production causing inner ear infections. Now a SNP test to determine whether you have a gene for dry earwax characteristic of Asians and Native Americans was announced by K. Yoshiura et al. in a letter in Nature Genetics 38 (Feb. 2006) 324-330. Here is an abstract:
Human earwax consists of wet and dry types. Dry earwax is frequent in East Asians [and Native Americans], whereas wet earwax is common in other populations. Here we show that a SNP, 538G right arrow A (rs17822931), in the ABCC11 gene is responsible for determination of earwax type. The AA genotype corresponds to dry earwax, and GA and GG to wet type. A 27-bp deletion in ABCC11 exon 29 was also found in a few individuals of Asian ancestry. A functional assay demonstrated that cells with allele A show a lower excretory activity for cGMP than those with allele G. The allele A frequency shows a north-south and east-west downward geographical gradient; worldwide, it is highest in Chinese and Koreans, and a common dry-type haplotype is retained among various ethnic populations. These suggest that the allele A arose in northeast Asia and thereafter spread through the world. The 538G right arrow A SNP is the first example of DNA polymorphism determining a visible genetic trait.
Europeans and Neanderthals Didn't Have Much Time to Get Acquainted, Much Less Interbreed
According to a report in the New York Times by
John Noble Wilford published February 23, 2006, new advances in radiocarbon dating are threatening to upend old theories about when modern humans migrated to Europe from Africa and how rapidly they advanced.
The research casts new light on significant patterns of human migration into Central and Western Europe in the crucial period from 50,000 to 35,000 years ago, scientists say. It suggests that the dispersal of anatomically modern Homo sapiens into Europe was more rapid than previously thought.
That, in turn, would mean that their coexistence with Neanderthals was briefer and that their introduction of cave art, symbolic artifacts and personal ornamentation occurred much earlier.
For years, it had been thought that modern humans from Africa began arriving in Western Europe at least 40,000 years ago, and so could have competed and mingled with the local population for at least 12,000 years. The revised dating of fossils and artifacts leaves much less time for two species to have been in close contact.
It can be assumend now from the revised chronology that the overlap between Neanderthals and new arrivals must be shortened to about 6,000 years in Central and Northern Europe, perhaps only 1,000 to 2,000 years in regions like western France.
Some Case Histories
By JENNIFER ALSEVER
From The New York Times, February 5, 2006
THE past comes at a price for Georgia Kinney Bopp. Retired and living in Kailua, Hawaii, Ms. Bopp has spent about $800 on tests to trace her ancestry, using samples of DNA from inside her cheek and from possible relatives.
She and her husband, Thomas, even plan vacations around genealogy research, seeking DNA samples from distant cousins.
"If we travel, we keep a DNA kit with us, just in case we meet someone who might help identify an ancient ancestor," Ms. Bopp said. "You just never know."
Several years ago, the Internet helped to encourage a greater American fascination with genealogy. Now DNA testing has added a new twist that has people like Ms. Bopp paying hundreds if not thousands of dollars to look at genetic information in order to uncover details about their heritage.
Read the whole article.
KENNEWICK MAN:
Court Battle Ends, Bones Still Off-Limits
By Constance Holden
From Science 30 July 2004: Vol. 305. no. 5684, p. 591.
When Native American tribes decided last week not to fight an appeals court ruling, it looked as though the way was clear for scientists to study the 9300-year-old skeleton called Kennewick Man, which has been tied up in legal battles for the past 8 years. But scientists say that although the ruling sets a favorable precedent for studying other ancient skeletons, they are not optimistic about getting to study Kennewick Man himself anytime soon. The government continues to find fault with outside scientists' research plans and to deny access to the remains. Negotiations are in progress, but the lawyer for the eight scientist-plaintiffs in the suit, Alan Schneider of Portland, Oregon, says, "we are still far apart." Going back to court, he adds, "is definitely a possibility."
The Kennewick case finally appeared to have come to an end on 19 July when the defendants, four tribal groups, decided not to appeal to the U.S. Supreme Court a decision by the 9th U.S. Circuit Court of Appeals....