The Big Idea: Nancy Kress

Hugo and Nebula Award winner Nancy Kress is thinking big about something small: Your genes. In the real world, they connect you, for better or worse, with every other human on the planet. In Kress’ latest, Yesterday’s Kin, they also connect with something else — something surprising.


Yesterday’s Kin is, at its heart, about mitochondrial DNA–which means that it is, at its heart, about what it means to be human.

Can you define humanity by its genes? Maybe not all of human behavior or growth or soul, but since 1981, you can define humanity’s past that way, in order to decide who is related to whom and how.

Somewhere in Earth’s deep past (very, very deep, possibly 1.5 billion years ago), an ancient bacteria merged with an ancient single-celled organism that already possessed a nucleus. It was a good marriage. The DNA in the bacteria evolved into mitochondria, little powerhouses that help convert oxygen into energy in every cell of your body. The DNA in the single-celled organism went on doing what DNA does: creating proteins and replicating itself. Everybody was happy.

However, mitochondria had a pre-nup that many Hollywood actors would envy. In the case of a cell split, a mitochondrion get to keep all its DNA and pass it on, unchanged, to the egg that will become the next generation. Sperm gets almost no mitochondria, and what little it does have is shed with its tail. Thus, all your mitochondrial DNA (mtDNA) came from your mother, who got it from her mother, all the way back to the common matrilineal ancestor, “African Eve,” approximately 6,000 generations ago. Humans can be grouped into “haplogroups,” clusters of people defined by their differences in mtDNA.

When I discovered all this, I was fascinated. Coupled with a higher mutation rate relative to nuclear DNA, the inheritance of unchanged mtDNA makes it possible to trace ancestry of a person, or groups of people, through the restless migrations that characterize our species. All sorts of anomalies abound: Why does the Korean sequence turn up regularly in Norway? How did that family on the Russian steppes acquire the mtDNA signature of a Polynesian? And what does any of this have to do with science fiction?

A concept is not a story. To turn my enchantment with mitochondrial DNA into something with the possibility of enchanting anyone else, I needed characters, plot, conflict, setting. This stalled the entire project for a year, while I pondered. Pondering is what writers do best, since it has the virtue of feeling productive without the pain of actually confronting a keyboard. Eventually, however, pondering must end and writing begin. For SF, aliens are often a good place to start.

In Yesterday’s Kin, aliens arrive on Earth. They willingly subject themselves to being sampled and probed: tissue, blood, organs, DNA. The results are conclusive: These aliens are human. Their particular migration reached farther, and deeper into the past, than any other—but how? When? And why are they returning now? The answers to these questions formed my plot.

My protagonist was created from twin desires. First, I wanted to portray contemporary biological science as it is actually done: with sophisticated equipment, as part of an international conversation, with career-impacting mistakes and triumphant corrections. Too often, the “science” in SF is of the cloning-in-a-basement-by-a-mad-scientist type, or else gibberish hand-waving (“If we hook up the actofrabble cycle to the Hartford drive, we can create galaxy-spanning life insurance!”). I have enormous respect for science and scientists (all right, I’m a science groupie) and I wanted to show biological discoveries being made under pressure, with the inevitable competition as well as the teamwork, as realistically as I could.

Second, I wanted a female scientist who (1) was not young, (2) did not tote a blaster, and (3) had a family. Humanity comes, of necessity, in families, at least in the beginning of lives, but from much science fiction, you’d never know this. Protagonists whiz around interstellar space unencumbered by so much as memories of anybody back home, much less the aching concern that most parents never lose for even their grown children. Dr. Marianne Jenner, evolutionary biologist, has three grown children, all of whom carry around the marks and scars of their upbringing. Just like (I fervently hope) real people.

Yesterday’s Kin was absorbing to write. During my research, which was extensive because I am not a scientist, I discovered enough material for several books in several genres. The United Kingdom, for instance, has recently approved the insertion of mtDNA from a donor egg into an egg whose own mtDNA carries inherited mitochondrial diseases. The donor mtDNA replaces the defective mtDNA. When the egg is fertilized in vitro, the resulting child will actually carry DNA from three different people. Legal thriller, anyone? Family saga? Star-crossed romance?  (“We can’t marry; you’re my one-third sister.”) However, SF is what I write, and with Yesterday’s Kin, Marianne Jenner’s story is not finished.

Nor are the surprises written in human mtDNA.  Your mitochondria supply you with more than physiological energy.  They can reveal our shared past and the connections that, to a large extent, make us who we are.


Yesterday’s Kin: Amazon|Barnes & Noble|Indiebound|Powell’s

Read an excerpt. Visit the author’s site. Follow her on Twitter.

14 Comments on “The Big Idea: Nancy Kress”

  1. As you have said elsewhere, DNA and genetic manipulations have *long* since been in your wheelhouse, back to Beggars in Spain.

    I look forward to reading what you’ve done this time out

  2. Side note: Precisely because mitochondrial DNA only comes from one parent, it would be exceeding silly to take account of it in determining what couplings should be legally or socially forbidden. Which is not to say that people necessarily wouldn’t, human rationality being what it is (and isn’t).

  3. What? Scientists as real people with real lives? How dare you?!? And then you cap it off by having the scientist be a talented, intelligent woman – don’t you know that we weed those out during Orals?


    Seriously, this sounds like a great book. Even better, it sounds like one of those rare things to be treasured: a book that gets the science right without sacrificing plot or character development. I look forward to reading it!

    However, I wouldn’t count “cloning in a basement” out. You are familiar with the “hand made” techniques using cow ova, aren’t you? Honestly, I’m surprised that there haven’t been some FFA projects based on that already.

  4. I am buying this. Nancy Kress’s last book, After The Fall, Before The Fall, During The Fall, was fantastic and lovely.

  5. Aaaand, bought! This will be great reading on my transpacific flight tomorrow. I love it when authors take the time and effort to get science right – faulty technobabble always hits my suspension of disbelief hard and can be pretty jarring. (Especially genetic technobabble, since one of my bosses is a genetics professor) Authors getting science right is awesome. (Nancy Kress does it, so does Mira Grant in her Newsflesh series, which I just finished binge-rereading).

  6. Purchased! I was tempted to get the Nook version because I want to read it NOW, but decided to be patient and wait for the hard copy (only 2 days with Amazon anyway…) because I have a feeling I’m going to want to shared this with my daughters when I’m finished reading it.

  7. Nancy Kress has never disapointed me, and her premise intrigues me. The scientific research sounds amazing, and her second-to-last paragraph made my head explode. Off to buy. . . .

  8. As someone who reviewed this book through NetGalley, I have to say it’s pretty good. I hadn’t actually read a book by Kress all the way through before, and that definitely needs to change.