01 September 2009

DNA: Dr. Michael Hammer, ancestor hunter

Many Jewish genealogists who utilize DNA genetic genealogy via FamilyTreeDNA.com have heard the name of the University of Arizona's Dr. Michael Hammer, 55.

Hammer is chief scientist for FamilyTreeDNA.com.

If you've ever wanted to know more about him, how he got involved in this field and much more, there's a great story here that spotlights him.

The University of Arizona's Michael Hammer is using advanced DNA techniques to figure out where we came from. Which, apparently, is not just one place, or even one species.
Some genetic genealogists think their own ancestors were aliens as they can't find a match.

Relative to Jewish genealogy, the story provides information on the Kohanim project and a paper he co-authored in 1997, there's information on both FamilyTreeDNA and the Shoah Project.

In other areas, the casually-clad scientist covers the deep anthropological roots of humans "out of Africa."

Maybe it's the scooter propped in the corner of his office, or the fact that he's wearing a T-shirt and denim cargo shorts while sporting a gold hoop in his left ear, but Michael Hammer definitely looks more like a surfer than one of the world's leading gene detectives. The maps are a giveaway, though. His tiny cell of an office, which looks out onto a grove of lazily waving palm trees, is decorated with several maps of the planet. He has more maps — colorful wall-sized affairs — in his various labs scattered around the University of Arizona campus. Standing back from one of these maps, Hammer can look deep into human history. He sees the movement of ancient Asians into the New World and the rapid expansion of seagoing peoples across the Pacific 3,000 years ago. He can even discern the migrations of our early ancestors out of Africa 60 millennia or so back in time.

For Hammer, a population geneticist, it is a story told in our DNA, the nucleic acid that transmits the information encoded in genes down through generations. Curled up tightly into chromosomes, DNA is a long, twisting ladder-like chain of thousands of simple molecules called nucleotides, lined up in pairs. These base pairs occasionally drop out or repeat in distinctive ways as the DNA is passed from parent to child.

Scientists can figure out when these base pair variations — single nucleotide polymorphisms — diverged from one another, allowing them to build elaborate family trees stretching back tens of thousands of years. In a 2008 paper, for example, Hammer found chromosomal evidence that throughout human history, men have generally produced more offspring than women. (He calls it the Clint Eastwood effect after the legendary actor/director, who fathered seven children with five women.)
The story covers cheek swabs, archaic hominids, the human genome, genetic code, technology, paleontology, Y-DNA, mtDNA, ancient migration, linguistics, anthropology, Japan, Korea, mathematical modeling, as Hammer always seems to be looking for the answer to "where do we come from?"

"It's genealogy at the level of families, genealogy at the level of distant cousins, genealogy at the level of populations that migrated in the last 3,000 years, all the way back to the genealogy of modern and archaic humans," Hammer explains.
Raised in Highland Park, Illinois, he was interested in marine biology but graduated from Lake Forest College with a liberal arts degree, but later was a molecular biology lab tech at the University of Chicago and then did grad work at UCBerkeley with late molecular biology pioneer Allan C. Wilson; he earned his PhD in 1984, did post-grad work at Harvard and Princeton and arrived in Tucson in 1991, where he developed the university's core genomics laboratory.

Eventually, he says, "I got interested in Jewish groups and the Jewish Diaspora and the peopling of Europe. It's like there are a million stories in the naked city."

"In most of our history, up through the past couple of hundred years, people really did sit where they were," Hammer says. "They really didn't move very far. So you get this nice gradient of variation that reflects these old, old migratory processes. I think it's one of the nicer examples of that."

Jews, whose Diaspora started with the Babylonian exile and continued through the Roman occupation, are something of an exception, having dispersed widely in western Eurasia and northern Africa. That prompted Hammer to wonder whether modern Jews retain close genetic links to their ancestors. "Are contemporary Jews descendants of Middle Eastern or biblical Jews?" Hammer asks. "Are they really converts? Was there so much intermarriage that the Middle Eastern genetic signal was diluted out?"

In a 2000 paper, Hammer and his colleagues reported that a comparison of Y-chromosome markers showed most Jewish groups were closely related to one another, despite having been scattered across central Europe, North Africa, Spain and Yemen. They showed only slight genetic admixture with their neighboring non-Jewish populations, but they turned out to be closely related to contemporary Palestinians, Lebanese and Syrians.
Officially, Hammer is director of the university's Genomic Analysis and Technology Core facility, which provides centralized training and DNA services, and the Human Origins Genotyping Laboratory, which performs high-volume DNA testing for both academic and private-sector clients.

Matt Kaplan, who spoke at this year's Philly 2009 International Jewish genealogy conference, is also in the story, as he supervises the Human Origins Genotyping Laboratory; he's one of Hammer's former graduate assistants who took part in some of the Jewish population research. The story details how DNA samples are processed.

Many of the swabs, sealed into small, fluid-filled tubes, come from Family Tree DNA, a Houston-based commercial testing venture for which Hammer also serves as chief scientist. Family Tree and Kaplan's lab are handling the public testing for The Genographic Project, a five-year research effort sponsored by IBM and National Geographic to create an inventory of DNA collected from around the world. Kaplan estimates the lab has tested more than 260,000 samples for the project since 2005.

Kaplan shows me a National Geographic map created depicting ancient migration routes around the world as deduced from Y chromosome and mitochondrial DNA. "You can actually swab your cheek and find out which one of those lines on the map is your paternal lineage," he says matter-of-factly. "It isn't magic. This is stuff we have been doing as academic researchers for years."
The story also covers the DNA Shoah Project, which Hammer co-founded, to create a database of genetic material from Holocaust survivors and their immediate descendants.

There's much more to the story, so read the complete article at the link above.

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