Even seated, Mary Haynes' body is perpetually in motion. Her torso lurches side to side when she speaks, while Mike Tossy's body is noticeably still. His eyes dart around, but his head rarely turns.

Both Haynes and Tossy suffer from Parkinson's disease — a neurodegenerative disorder affecting nearly a million Americans. They are also two of 11,000 customers of 23andMe with Parkinson's participating in the DNA testing company's research program.

By analyzing the customers' DNA, the Mountain View company has helped discover eight new mutant genes linked to the disease. Now Haynes and Tossy could be asked to make their genetic codes available for deeper scrutiny — a possibility that would test the boundaries of privacy in medical research.

In January, the DNA testing firm announced a $10 million deal with Genentech to give the South San Francisco pharmaceutical company access to the genetic data of 23andMe's customers with Parkinson's.

It's a new Silicon Valley frontier: Just as marketing companies are mining your Internet browsing habits to design the killer ad, new technologies are allowing pharmaceutical companies like Genentech to mine our DNA to create the next generation of drugs.

The collaboration between the two valley firms is aimed at uncovering proteins responsible for the disease, but it also raises some privacy concerns for customers of 23andMe who have previously agreed to give the company and its partners access to their genetic data — and who may now be asked to release even more information about themselves.

Haynes, 69, of Capitola, is only partially wary. She says she realizes "it makes me kind of a guinea pig," but believes that "anything that moves us towards a cure is OK with me." And Tossy, a Soquel resident, feels the same way.

For now, Parkinson's is shrouded in mystery.

No single gene is responsible for the disorder. A few mutated genes have been linked to it, but the majority of those who suffer from Parkinson's have healthy versions of these genes. Scientists think it results from a subtle interplay between environmental factors and a multitude of genes that causes key neurons to die.

By the time symptoms — a hand tremor or a stumbling gait — appear, more than half of these cells are dead, or nonfunctioning.

Drugs like Levodopa or brain surgery can slow the progression, but eventually patients lose control over their bodies and need constant care.

Genentech hopes to use 23andMe's massive database to gain new insight about what may be breaking down inside the neurons. "We're hoping it gives a clue about Parkinson's genetic Achilles' heel," said Tim Behrens, Genentech's senior director of human genetics.

It was 23andMe's personal connection to Parkinson's that makes Haynes trust the company's intentions. The company's co-founder and CEO Anne Wojcicki's estranged husband, Google co-founder Sergey Brin, is a carrier for a mutant gene that increases his risk for Parkinson's. Brin's mother has the disease.

Scientists often talk of "reading" DNA. The human genome has about 3 billion "letters" — the chemical subunits that make up someone's DNA — but only a tiny fraction of these letters code our genes.

Currently, 23andMe uses DNA chips to analyze 750,000 letters, less than 1 percent. For the Genentech study, 23andMe will sequence the whole genomes of 3,000 customers.

"This will be one of the largest genetic studies that has ever been done in Parkinson's," said Todd Sherer, CEO of the Michael J. Fox Foundation.

When customers sign up for 23andMe's research group, they agree to allow the company or outside researchers to search for patterns in their DNA. Their account details — names, email addresses and credit card numbers — are separated from their genetic data and surveys that reveal their medical histories.

Right now, 23andMe researchers never have access to a single person's results. But they can, for example, compare women with Parkinson's who were diagnosed in their 50s and find out what percent have a particular gene variation.

The new deal with Genentech grants a different level of access.

Scientists will be able to explore an individual's DNA. Looking at Tossy's genome file, for example, they wouldn't know his name, but they would know that he was a 58-year-old male and they could identify the file of his mother — a 23andMe customer with Parkinson's — based on his DNA sequence.

To include Tossy, or his mother, in this research, both would have to sign new consent forms.

John Simpson, the privacy project director of Santa Monica-based Consumer Watchdog, believes such an "opt-in" approach is the right way to proceed, but he hopes the companies make data and approaches as transparent as possible. "They have a responsibility to keep the research subjects fully informed about where the research is headed," he said.

Tossy said he would be willing to give 23andMe that permission, but he'd want to know that his data would be used strictly for Parkinson's research.

There are several protections in place. Genentech will have exclusive access to data for a limited time. And the specifics of what they can review will be overseen by an independent institutional review board.

Parkinson's research and advocacy groups are enthusiastic about the possibilities of the collaboration. "We're excited to see the industry stepping in and making a major investment in Parkinson's," said Parkinson's Institute's CEO, Carolee Barlow.

For Tossy and Haynes, it's more personal. "The disease marches on," Haynes said, "and the part of our brain that is doing this is getting smaller and smaller."

Contact Kim Smuga-Otto at 408-920-5764. Follow her at Twitter.com/kim_smuga.