My father was Susquehannock, a forgotten Indian tribe from Pennsylvania. He grew up in inner-city Philadelphia but moved west and met my mother. She has a bit of Indian blood (an eighth, a 16th, a 32nd?) from her father’s side, but otherwise she is broadly European. As a child, I clung to the extra few percentages she provided because people always reminded me I was not white. If I couldn’t be white, it wasn’t enough to be half-Indian for me either. Indianness gave me legitimacy. But still, many of my childhood memories bear the stain of the innocent cruelty of other children. They called me Squanto and my sisters Pocahontas, threatening to give us pox-laden blankets, promising a new Manifest Destiny, or Trail of Tears. They included me only to play cowboys and Indians – and always obliged me to lose.

This cruelty didn’t stop with children. I remember the second-grade teacher who inspected my hands to make sure they were clean, and who sent and resent me to the bathroom throughout the year to clean them. I remember scrubbing my hands before school to the point of bleeding to avoid these inspections. And when there was not cruelty, there was the general racial illiteracy of well-meaning adults, including my own family.

I clung to those few maternal genetic percentages, as I find myself unwittingly clinging to them sometimes now, because Indianness structures my experience. I understand the world in terms of being Indian: it is built into the fabric of who I am. Just as my relationship with my father is built into the fabric of who I am. He is a difficult man, though, and my relationship with him has always been strained. In the past 20 years I have seen him twice and only spoken to him a dozen times. He left us and left California, where I grew up. I too left, eventually. Moving first to New York and then to Europe. I go back rarely.

In recent years, my mother’s sister became interested in DNA testing and she pushed my reluctant sisters to do it. We couldn’t have expected the results that ensued: having first found my younger sister through her DNA ancestry account, a woman contacted her on Facebook. The woman said that she thought her brother was our father. This seemed impossible – my father had never mentioned any sister. Then came wave after wave of photos. Each had a man in it that bore a troubling resemblance to him, only younger, from an age where there had been no previous visual record.

From this woman, my sister found out that our grandfather was born in China and emigrated to the US in his 50s. He settled in Philadelphia. There, he opened a Chinese restaurant and started a relationship with a black teenager, our grandmother. The story continues that their son, my father, became involved in gangs in Philadelphia and was in and out of juvenile detention centres. Why, I don’t know. I have received no clear answer, only allusions to violence and drugs. It was apparently in these detention centres that he was given the idea that he physically resembled Indians – and became fascinated by them. After he got out, he left his family and the east coast, starting a new life with new people – and with a new Indian identity.

‘I was already in my 30s when my Indianness was pulled out from under me.’ Photograph: Sequoya Yiaueki

As he built a new family something always bucked against his ability to be present and stable in our lives. Eventually, as we got old enough to ask questions and to seek some form of coherence for ourselves in our lives, he left again.

In recent years there has been a rise in the use home DNA kits and genetic testing sites like 23andMe, Ancestry.com and DNA.com. As more people turn to these relatively inexpensive services to learn about their historic makeup, the UK’s Human Fertility and Embryology Authority has warned users to be prepared for unexpected results these tests can throw up. The authority has called for the “sites to do more to inform users about the potentially unwelcome consequences of tracing their genetic relatives”.

I was already in my 30s when my Indianness was pulled out from under me. It had taken me years to settle what I thought about race. Take, for example, the term Indian. It has wide use, both inside and outside those patches and corners of land called Indian Country that remain tied to the first humans in that part of the Americas. I asked myself whether I should I use the term, or whether I should use Native American, or First Nations, or Indigenous, or Aboriginal. There is an artificiality to all of them and so my preferred usage became Susquehannock, but I eventually made peace with the term Indian. That peace is now disrupted.

When I was Indian, my choice highlighted that there are many ways to perform race and that I had found my own way of performing Indianness. But now that I talk and think about my identity in past tenses, what right do I have to decide how Indianness is performed? My father clearly had no right to that decision, but because he passed successfully, I had only ever been Indian.

According to the mapping features of the service my younger sister used, I was only ever 9% non-specific East Asian/Native American. (This service breaks down each percentage and generates a map of your genetic geography, detailing genetic makeup in descending order.) This dubious 9% is a far cry from the Indian identity I had always believed myself to have. I had felt that although I didn’t belong in the groups around me, in the deepest sense, being Indian, I belonged in the Americas in a way that the descendants of European settlers never would. I was proud of that, because it was something that couldn’t be taken away – until it was.

Now, after the fact, there is no simple answer to how I feel. I want to resent my sisters for doing the DNA test because my chances of having a better relationship with my father are damaged, but I don’t. I do, however, resent the insistence with which my aunt had pushed my sisters to take these tests. And the smug satisfaction with which other family members rushed to remind me that they always knew my father was full of shit. My sisters and I knew that he lied; we were just never sure what he lied about. We were always nervous to pull at a thread that would unravel all that we knew about him. So, I resent that I couldn’t discover who my father was on my own time. I still love him despite the dissonance between the man I speak to on the phone every once in a while, and the severe but very human person I once knew. I called my father after I learned the news of our changed identity – he said one thing before hanging up: “Goddamn motherfucking internet – why can’t people leave the past the past?”

I often wonder about his question. DNA tests can stir up things people were trying to hide – sometimes for legitimate reasons. What was he running from? Do people run just to run, or do they necessarily run from something in particular? If the racial climate in the US is any indicator, he may have done it for good reasons. But that alone doesn’t seem to be enough. What else was there?

Upon discovering what seems to be my father’s true identity, new members of his family have been revealed to us. My sisters have met them, but I still have not. From afar they seem like fine people, but is that always the case? Does everyone who takes DNA tests stumble on to warm, loving, healthy situations? I doubt it. For the idle curious, genetic testing can be a fun adventure, but for some of us, the stakes are far greater and the dangers are more real.

‘DNA tells us lots of interesting things, but it is not definitive.’ Photograph: Alamy Stock Photo

It is not surprising that DNA tests have real risks. It asks the question of who we are head on. This question is far from being settled, but it is one of the essential ones we ask. Much of the history of thought is born out of it. Heraclitus incited everything from philosophy to physics with the idea that no one steps into the same river twice. Everything, he claims, from the river to the person doing the stepping, are subject to change. The ancient thought experiment, the ship of Theseus, asks how we are to understand permanence in objects. Is a ship the same ship if, to fight rot and the other ravages of time, we change one plank, and then another, and then another, until there is nothing of the original ship left? These metaphysical problems about permanence and change hide a methodological problem about how we define what is changing and what is staying the same.

DNA tells us lots of interesting things, but it is not definitive: it can only dig so far back before it starts depending on things other than DNA to make sense of the data. In other words, if DNA goes back far enough, Englishness, for instance, gets lost in the melting pot of its own past, from its colonial empire to its early Brittonic settlers. How do we decide which different groups matter to English identity? Surely not DNA tests, because some notion of identity already has to be in place in order to decide what to look for in genetic markers. Even at its best, DNA only answers a certain type of question about who we are.

Some thinkers argue that this metaphysical question about the sameness of substance is on the wrong path for understanding human identity. One such thinker, Paul Ricoeur, thought that such sameness misses a specific ethical and imaginative aspect of our identity called selfhood. He creates the notion of “narrative identity” in order to move us past the question of who we are as objects towards the question of who we are as agents. This narrative identity is supposed to be formed by the stories that we tell and that others tell about us. It is the unity of these stories that allow us to create a unity in our life. There is something compelling about this. I don’t feel different as a person, and I see part of my story as a continuity. However, there are limits to this notion.

My own story puts me face to face with a specific kind of rupture. The stories I have told about myself my whole life are based on certain material aspects that my narrative self depended on. Now, I am working from a fractured narrative because of a material change. But this cannot be reduced to the ancient problem of change either. I am not changing one plank at a time, rather I have found that there was never any ship. But I still try to stay afloat. This is hard, because even with stories, even with data, we navigate our lives unaware of the reefs that lie in wait, whole ecosystems of secrets ready to sink us should we run aground in them.

• Sequoya Yiaueki is a philosophy PhD candidate, writer, and translator living in France