Spotlight on Ohlone

Professor explores genetics through time

By Andrew Cavette.

Thursday, September 13, 2007 — Monitor.

The slide showed a scraggly stretch of desert in Ethiopia.  Professor Mark Barnby darted back and forth between his laptop and the front of the stage.  “If you’re looking for Eden,” he commented, “this might be it.”

The semester’s first Brown Bag Science Seminar, held last Friday, drew a near-capacity crowd.  According to Math, Science and Technology coordinator Yvette Niccolls, the first Brown Bag of the semester typically does not have high attendance.

After Barnby gave his lecture on mitochondrial DNA, however, Niccolls looked back at the departing audience.  “The house was packed,” she said, beaming.

Though not every seat in Room 2133 was filled, one certainly would have had some toes left over counting the empty chairs. Niccolls attributed the surprisingly large turnout to both Barnby’s personal animation and the topic itself. Molecular anthropology, the study of human migration by the tracking of genetic markers, crosses over many different fields.  The topic has “not only scientific interests, but also religious ones,” Niccolls noted.

Barnby’s lecture covered a string of scientific fields from the study of fossil records and archeological data to the anatomy of human sex cells and DNA sequencing; all with the daunting yet fascinating task of finding out where our ancestors went when they left the house, 50,000 years ago. We are able to track the maternal lineage of the human species because, as Barnby notes in his lecture, “the copy machine is not perfect… mistakes are made.”

These mistakes are genetic mutations and these mutations are passed to new generations on the mitochondrial DNA. When a group is separated for long enough, say by migrating slowly along the coast of India for several thousand years, they lose ties with the original population.  

This new population begins to breed within their large, separated group, isolating themselves genetically. When this happens, scientists can look for mutations specific to that population, called genetic markers, and follow those markers as people spread across the continent.  

According to Barnby, though “Mitochondrial Eve,” an African woman who lived 150,000 years ago, was not the only woman alive at that time, “everyone on Earth today has her mitochondria.” Until very recently it was believed the various pockets of older species of the genus Homo evolved into their modern geographical equivalents, older species of Homo in Asia simply evolved into the Homo sapiens of Asia while older species of Homo located in Europe likewise would have changed into the Homo sapiens of Europe.  

In the last five or 10 years, molecular anthropology has suggested this may not be true.  The data which has been collected so far shows that perhaps the older species of the genus Homo were slowly displaced by the ever encroaching Homo sapiens, relatives of Mitochondrial Eve.  This displacement would have been far-reaching  and slow moving as her extended family made their way into all corners of the continent, as well as over the Bering land bridge into the Americas.

Though scientists have already collected a large number of samples, this field is relatively new.  “We don’t have 6 billion samples yet,” Barnby joked.  

There is much work to be done, and Ohlone College is doing some of it. As part of course instruction on how to use Ohlone’s own DNA sequencing technology, Barnby and his students contribute data to a website run by the National Center of Biological Information.

During the lecture, Barnby shared the results of data collected on his wife’s family who, as it turns out, were part of the first migration into Europe. He also shared the results of samples taken from Science and Technology Dean Ron Quinta, who is part of another early European migration.  The PhotoShopped image of the Dean-As-Caveman made everything clear, except the audience’s tearing eyes as they recovered from laughter.

When a student asked how he could track his own ancestry, Barnby told the audience about the Genographic Project Public Participation Kit which is available at the website for the National Geographic Society (https://www3.nationalgeographic.com/genographic/participate.html) According to the website, “Your results will reveal your deep ancestry along a single line of direct descent and show the migration paths they followed thousands of years ago.”

After the lecture ended and most of the attendants were on their way, a small group of students congregated around Professor Barnby.  Synapses alight with this new information, they each had questions or needed clarification.  

Most of their questions centered around one theme.  A young woman in a crisp, red track jacket apologized to the others, politely pleading one last question.  “I’m sorry… I know it’s selfish” she said, asking which branch of the migration Iranians belonged to.  

It seems people have more in common than mitochondria; No matter where they have gone, they want to go home.

The next Brown Bag Science seminar will be Friday, Sept. 21 from 1 to 2 p.m. in Room 2133. It will be entitled “Wild Edible Plants” and will be about the plants the Ohlones ate. The speaker will be Professor Gessica Johnston.

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Related Links at Ohlone College

• Brown Bag Seminars - Science & Technology