It started with a phone call. Doesn't it always?

Although my cell phone was resting face down on the patio table within easy reach, vibrating noisily against the glass, I almost didn't pick up. My hands were encased in rubber gloves while I smoothed marine varnish over the sun-bleached teak of our deck chairs. I could tell by the ringtone, however, that Georgina was on the line. I knew from experience that she'd keep dialing my number until I silenced the chimes either by switching the phone into airplane mode or chucking it into the rhododendrons. So, I caved.

I dunked the paintbrush into a yogurt tub filled with paint thinner, peeled off the gloves and used a damp pinky finger to accept the call.

'Hey,' I said as I leaned over the table and stabbed the speaker button. 'What's up?'

I hadn't heard from my baby sister in two or three weeks. It's probably not nice to say, but Georgina usually called only when she wanted something. I braced myself.

'Did you ever send in that DNA test kit I gave you?'

Georgina had been dabbling in genealogy lately, exploring the Alexander family tree. How she found the time between caring for four school-age children and Scott, her high-maintenance, self-employed CPA husband, I couldn't imagine.

'Not yet. Why?'

'I don't know why I even bothered to give it to you, Hannah,' she huffed.

'I'm sorry, sis. It slipped my mind, is all. I'll get to it soon, I promise,' I said as I puzzled over where I'd put the damn packet. At a family picnic a couple of months before, Georgina had given me and our older sister, Ruth, each a test kit. At the time, she'd seemed eager – with Scott egging her on – to join the Daughters of the American Revolution which required tracing our forefathers (and mothers, Ruth had been quick to remind her!) in an unbroken line back to 1776.

'How hard can it be to spit into a tube?' Georgina sighed in exasperation. 'And postage paid?'

'Sorry,' I apologized again. 'Is it important?'

'I don't know,' my sister said, sounding cautious. 'It's just that I think they might have made some sort of mistake when they tested mine.'

'Yeah?'

'The English and Scottish roots I expected,' she continued. 'There was a smattering of Scandinavian and Iberian Peninsula that didn't surprise me, the Vikings and the Romans, you know,' she rattled on, 'but according to Gen-Tree ...' She paused. 'Are you sitting down?'

'Don't build me a clock, Georgina. Just tell me what time it is!'

'Gen-Tree says I'm twenty-five percent Native American.'

I reached for a chair I hadn't yet painted and sat. How could my fair, green-eyed, red-headed sister, and by extension Ruth and I ...?

The Alexanders, I knew, emigrated to Virginia from the Scottish Highlands sometime in the mid-eighteenth century, and our mother's family, the Smiths, descended from frugal, Puritan stock, going back – Grandmother Smith always claimed – to 1630 and the Winthrop Fleet. My husband, Paul, used to tease that this explained my propensity to rinse out and reuse Ziploc bags.

'That's nuts,' I said, after catching my breath. 'It's probably a mistake. Got contaminated, or your sample mixed up in the lab with somebody else's.'

'That's what Scott thought,' Georgina said.

'Call them,' I suggested. 'Ask them to re-do it.'

'I did, Hannah, and they're sending me another test kit for free, but it'll take weeks and weeks to get the results! That's why I was hoping you'd sent yours in. I mean, we should be the same, right?'

'As far as I know. Have you checked with Ruth?'

'She flat-out refused to do it. Hutch said he had serious privacy concerns about those testing companies.'

Ruth's husband was an attorney. He always agonized over the fine print.

Frankly, I thought it'd be rather cool to have Native American blood, but I didn't see how that could be possible. Twenty-five percent? I did the math.

If that were the case, one of our four grandparents would have to have been a full-blooded Indian. I'd known my grandparents on both sides – they'd lived well into their eighties. A long-ago Alexander had migrated from Virginia to southern Maryland where he married a sixteen-year-old Catholic girl related to George Calvert, the first Baron Baltimore. I'd forgotten the fellow's name, but the couple prospered, growing tobacco on a Chesapeake County farm not far away from the one now owned by my husband's sister, Connie. She raised cows down there, though, not tobacco.

Stephen and Charlotte Smith had been farmers, too, on a two-hundred-acre spread near Norwich in rural Vermont, now home to a Christmas tree farm run by one of my second cousins. A cemetery not far from the King Arthur Flour Company was chock-full of our relatives. A wedding photograph still sits on my living room mantel: Grandpa Smith, string bean tall, his sandy hair sticking out in tufts from beneath a broad-brimmed hat. Grandma, diminutive, deceptively frail, her peach-colored hair in full bloom around her face.

'Hannah? Are you still there?'

'Sorry,' I said. 'I was just trying to wrap my head around all this. Honestly, I don't recall any one of our grandparents having Native American features, but I'm not sure what I'd be looking for.'

'Maybe Mom or Dad was adopted,' Georgina cut in. 'Or maybe ...' She paused dramatically. 'Maybe there were shenanigans.'

I laughed out loud. 'Let's wait until our tests come back, OK?'

She giggled. 'OK. Thanks for putting up with me, Hannah.'

Georgina could be a handful, that was certainly true, but it wouldn't help to agree with her. As I watched the varnish in the open paint can start to skim over, I tried to remember where I'd put the darn test kit. Under the bathroom sink?

'Hey!' Georgina was saying when I tuned in again. 'You're much better with computers than I am, Hannah. How 'bout I set you up as co-editor on Gen-Tree.com? You can check out the information I've entered so far. Do a bit of poking around.'

'Sounds like fun,' I said truthfully. I'd seen the ads for Gen-Tree on television. Click on one ancestry hint – a flapping pennant icon – then another and another, leading back to – potentially – Adam and Eve. It could end up being more addictive than playing Words With Friends. 'Maybe there'll be horse thieves in the family, or moonshiners,' I mused.

'Then again,' Georgina said, 'they could all be totally boring. Like accountants.'

After we said goodbye, I capped the paint can, cleaned the paintbrush with turpentine and trotted upstairs to shower. The Gen-Tree test kit was, as I suspected, under the bathroom sink. After I dried myself off, I put on a fresh top and a clean pair of shorts, grabbed the kit and padded barefoot down to our basement office. I sat down at the computer. While I waited for it to power up, I opened up the packet and read the instructions.

Activate the fifteen-digit code. Check.

Agree that I can't sue the company for DNA results I didn't like. OK.

Receive emails from our business partners? I don't think so.

Health reports? You bet.

I also agreed, in spite of the vagueness of the wording, to allow my DNA to be used for projects to 'better understand the human species'. Why not, I reasoned. It's the closest I'll probably get to doing scientific research.

When I got to the section about DNA matching, I called Georgina back.

'When you sent in your sample, did you sign up for the DNA matching service?' I asked.

'Gosh, no. Scott had a fit when I mentioned it. He even made me check the box instructing them to destroy my sample after they tested it.' She paused, then said slyly, 'But that wouldn't prevent you from signing up for it.'

'Of course not,' I said as I checked the box that would allow Gen-Tree to match me up, DNA-wise, with potential relatives in their database, unsurprised to hear that Scott had kicked up a fuss. My brother-in-law left claw marks on the road as his family dragged him into the digital age. He used email in his work now, but still didn't 'do' Facebook or Twitter and had only reluctantly allowed his children to join the scary new world of social media.

Recently, a serial killer had been tracked down by matching DNA left at a crime scene to distant cousins registered in GEDcom, a public genealogy database. I hadn't murdered anyone recently, so adding my DNA to the pool didn't seem a particularly risky decision.

You were instructed to wait an hour without eating, drinking or smoking before taking the test. I figured the meatloaf sandwich I'd had for lunch was long off my breath, so I obediently spit – and spit and spit and spit – into the tube they provided. When the spit reached a black line, I screwed down a cap containing a blue liquid preservative and shook it for the required five seconds. That done, I slid the tube into a little bag, and the bag into a small, postage-paid box.

Ten minutes later, I intercepted the mailman as he strolled from house to house down Prince George Street. I traded the box for a packet of bills and advertising flyers. 'Take good care of that,' I said.

He scrutinized the mailing label. 'There's a lot of this going around.'

I grinned. 'We could compare notes. Maybe we'll turn out to be fifth cousins.'

'My wife found out she has a German half-sister,' the mailman commented as he tucked my precious cargo into a side pocket on his pouch. 'Seems Daddy was a naughty boy while stationed with the Air Force in Ramstein. It's a good thing he's already dead, or Mary's mother would have killed him.'

'I doubt there'll be any surprises,' I said with a smile. 'My family's so conventional they could have starred in a fifties sitcom sponsored by Walt Disney.'

'Well, good luck,' he said, touching the brim on his cap.

'Thanks,' I said over my shoulder as I returned to the house.

According to Gen-Tree.com, it would be at least six weeks before my test results would be ready. In the meantime, I decided to sit down, roll up my sleeves and see what I could discover by exploring their database.

I spent the remainder of the afternoon in the basement office, fleshing out the Alexander family tree started online by my sister, Georgina. I was new to genealogical research, but I immediately ran into what must be every genealogist's nightmare: a relative bearing the last name of Smith.

We had a Zebulon in the family woodpile, and a great-grandfather married to a woman named Azubah, but otherwise ordinary Johns, Marys, Sarahs and Abrahams appeared in biblical abundance throughout New England, and Mother herself was just plain Lois Mary.

As I explored the Gen-Tree database further, half the population of Vermont seemed to be Smiths, including Joseph Smith, of magic spectacles, golden tablets and Angel Moroni fame. The founder of Mormonism turned out to be, when I clicked down to it, my sixth cousin several times removed, depending on how one calculates those things.

As far as Smiths in my direct line were concerned, however, the closest Native American connection I could find happened on July 18, 1694 during King William's War. On that day, several hundred Abenaki Indians led by two French priests, massacred nearly everyone in my ancestors' village on the Oyster River near present-day Durham, New Hampshire. 'Just think,' I said to Paul, who had been hovering behind me for twenty minutes, kibitzing, insisting that I open intriguing Family Story documents and read them. 'If eight-year-old Mary hadn't scooted out the back door and hid in the woods while her family was being scalped, I wouldn't be here today.'

'Thank you, Mary,' Paul breathed close to my cheek.

Dad's family, the Alexanders, descended from sturdy, Scottish stock. Our dad was a George from a long line of Georges who were fairly easy to track through successive US censuses, not having moved around a lot during the previous three hundred years.

'If you're going to keep interrupting,' I said while typing, adding a trio of siblings to the Alexander line, 'do something useful, like massage my shoulders.'

'Have you run up your grandmother's line on your father's side?' he asked, applying gentle kneading pressure to my aching muscles.

'Not yet,' I said, leaning back gratefully and surrendering to his magic fingers. 'Right now I'm trying to clean up the mess Georgina's made. She's got one of our great-great-grandmothers married to herself and two of the poor woman's children born years before her marriage, which would probably have been a big no-no back in 1820.' I corrected the spousal connection, then clicked off through the database in search of Sam and Maud Alexander's marriage record.

Working on Gen-Tree was as addictive as playing the quarter slots at Atlantic City. I'd just be thinking of quitting and then ... I'd click on one more pennant. And then, well, OK, maybe one more. Before long, I had followed a promising hint and found myself back in Vermont with the Smiths.

My third great-grandmother on my mother's side, Helen Smith, was one of thirteen children. Four of the poor woman's ten children perished in a typhoid epidemic in 1856 while still in their teens. 'I. Can't. Even,' I muttered, as I linked to a photo of a weather-worn tombstone for sixteen-year-old Abigail that someone had posted on FindAGrave.com.

'That's why they had big families,' Paul offered, not so helpfully.

'Some simply can't manage it,' I said, indicating an icon of a sorrowful angel. Back in 1876, baby Richard lived for six hours, and his mother died the following day.

I'd lost a baby sister, Mary Rose, to crib death, and even after all these years, the memory still stung. 'Vermont keeps terrific records,' I said, moving on quickly before I could tear up, 'but some other states, not so much.' Baby Richard's father had remarried, but I lost track of him after the 1880 census. The entire US census for 1890 had been destroyed in a fire at the Commerce Department in Washington, DC, and by the time the 1900 census rolled around the guy had disappeared.

'What are you looking for, exactly?' my husband wanted to know. 'I can't see how tracking this dead boy's father is going to get you any further along on the Native American question.'

I clicked on my own icon – my senior yearbook picture from Oberlin College, the one where I was rocking the Dorothy Hamill wedge – and displayed my immediate family tree. My parents, four grandparents and eight great-grandparents lined up in rows of tidy boxes. 'If I am one-quarter Native American, it stands to reason that it happened in this generation here,' I said, indicating the row of boxes representing my grandparents.

Although my mother had died fairly young of congestive heart disease following decades of smoking, the four grands had lived long and happy lives, until – as one death certificate had put it – 'a surfeit of years' had carried each of them away. Earlier, I had uploaded family portraits of each of them. 'Nobody looks the least bit Native American,' I pointed out.

Paul leaned closer to the screen, adjusted his reading glasses to better study the images. 'I'd have to agree.'

'I wish I could ask Mom some questions,' I told him.

'You can't assume it's on your mom's side of the tree,' Paul said. 'Could be your dad. He's still alive and kicking. Why don't you ask him if he remembers anything?'

'I plan to,' I said, 'but he's been away. When I talked to Neelie the other day, she mentioned he's off in Florida tweaking some component on a SpaceX guidance system.'

Cornelia 'Neelie' Gibbs was my father's long-time girlfriend. Why they hadn't tied the knot, I couldn't say, although I suspect it had something to do with the retirement benefits from Neelie's late husband which, I gathered, had set her up for life as long as she didn't remarry. It didn't trouble me that Daddy was 'living in sin' with Neelie, but it had been an issue for Georgina's husband, Scott Cardinale. A 'recovering Catholic', he dragged his family off every Sunday to an evangelical mega-church just outside the Baltimore beltway, where he served as Treasurer, taught Sunday School, and led a Wednesday night Bible study class. 'I called Dad's cell and left a message for him to call,' I said. 'But I didn't say exactly why.'

Paul pulled up a chair and sat down next to me. 'Meanwhile, since you don't have your test back, and just for the sake of argument, let's assume that Georgina's results are accurate.'

'OK.'

'First scenario. Your DNA is relentlessly North European and Georgina's adopted.'

'Impossible. I remember when she was born. Mom was so pregnant she couldn't fit behind the wheel of a car.'

He held up two fingers. 'Second scenario. Your dad's in the Navy, on active duty. Maybe your mom had an affair while he was deployed?'