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Chance in the House of Fate: A Natural History of Heredity

Chance in the House of Fate: A Natural History of Heredity

by Jennifer Ackerman

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Award-winning science writer Jennifer Ackerman investigates the endless mysteries of genetics, offering an elegant natural history of humanity as seen through the lens of our genes and cells. Combining the gifts of vision and language with in-depth knowledge, Ackerman explores the ways in which, at the most fundamental level. humans are genetically linked to every


Award-winning science writer Jennifer Ackerman investigates the endless mysteries of genetics, offering an elegant natural history of humanity as seen through the lens of our genes and cells. Combining the gifts of vision and language with in-depth knowledge, Ackerman explores the ways in which, at the most fundamental level. humans are genetically linked to every part of the natural world. Chance in the House of Fate is a rich and often personal tour through the surprising turns of heredity, informed by the ways genetic inheritance has affected Ackerman's own life. From a younger sister's profound retardation and her mother's illness to the births of her own healthy daughters, Ackerman presents her experiences as telling touchpoints, ultimately illuminating the hidden biological connections among all forms of life.

Editorial Reviews

From the Publisher
"...graceful, nearly lyrical at times...The way in which she focuses on the beauty of scientific language enriches her expertise." Bookpage

"ponders the complexities of a common genetic inheritance among diverse organisms, from fruit flies to human beings" -Science News

"...a beautiful story of the natural world that will inspire and educate without dampening wonder." The San Francisco Chronicle

...graceful, nearly lyrical at times...The way in which she focuses on the beauty of scientific language enriches her expertise.
Publishers Weekly - Publisher's Weekly
Ackerman (Notes from the Shore) offers another series of natural science essays, this one concerning the continuity and discontinuity of cellular, sometimes molecular, existence. A fascination with the "natural history of heredity" may be written into Ackerman's DNAher youngest sister has a rare genetic syndromeand propels her career as a science reporter, so that even the mechanics of genes make for quite personal reporting, early Annie Dillard-style (viz. her conception of genetics as "the past whispered in bone and blood"). Terms that many readers will recall from biology texts become for Ackerman, a relative newcomer to molecular science via the biology "of the whole organism," characters in a thrumming, deep-time performance piece by proteins, enzymes and mitochondria: "the cosmos of molecules and cells has surprising beauties and minute dramas." She chases her themes in and out of the nucleus, up and down the phylogenic tree from E. coli to the giant squid's eye to her own daughters in uteroall points of departure for 18 energetic expositions on genetics and other biomechanisms like morbidity, sexual reproduction, the immune system and the oldest of senses, smell. Some attempts to project the microscopic up to a visible-to-laypersons scale fall flat, but her style overall is a sweet hybrid of popular science and expansive prose. A sense of wonder and clearheaded respect for the raw biochemical chance that shadows evolution leads Ackerman into interesting corners not explored in recent genetics titles like Matt Ridley's Genome. Agent, Melanie Jackson. (June 1) Forecast: Ackerman will tour as part of Houghton's Literature in Science series. The house is bullish on her, and booksellers love her, too. With handselling and good reviews, the first printing of 25,000 should sell nicely. Copyright 2001 Cahners Business Information.
Library Journal
Recent discoveries in molecular biology have shown that genes governing life processes in widely different organisms from yeast to humans are essentially alike. That is the underlying theme of this book as it looks for meaning in the natural world while exploring complex questions in molecular genetics. Ackerman, a former staff writer for National Geographic and a nature author (Notes from the Shore), weaves her own personal experiences into this popular account of the natural history of heredity. (When she is pregnant with her first child, Ackerman worries that the baby will inherit the gene that caused the retardation of her younger sister.) Moving from topics such as development and sex determination to biological clocks and cell death, this is an engrossing book written in delightful prose that will please most readers. [Previewed in Prepub Alert, LJ 2/15/01.] Leila Fernandez, Steacie Science Lib., York Univ., Toronto, Ont. Copyright 2001 Cahners Business Information.

Product Details

Houghton Mifflin Harcourt
Publication date:
Product dimensions:
6.00(w) x 9.00(h) x 0.56(d)

Read an Excerpt


There are mysteries in all families. Those that arrest me, that set
me back on my heels, are the mysteries of heredity -- the past
whispered in bone and blood; the dozens of ancestors rolled up in one
skin, to be read in “curve and voice and eye,” as Thomas Hardy
wrote, “the seeds of being that heed no call to die” but turn up
again and again on the doorstep like a ne’er-do-well uncle. It seems
astonishing that a sweep of eleven generations hardly modifies the
night blindness of one family or the trembling jaw of another, that
fifty or a hundred years may fail to alter a familial pattern of
whorled eyebrow or “wolf’s” teeth, the musical genius of the Bach
family, or the dimpled chin of my husband’s tribe.
In the last decade or so, a startling new message has come
out about the long hold of heredity. Members of the human family
carry traits that have held on down the line not just for generations
but for eons, traits that mock all boundaries of time and kind.
Scientists probing the deep workings of organisms from yeast to
humans have turned up news that despite our outward differences of
life and limb, we are run by similar genes and proteins, similar cell
parts and mechanisms, which have weathered evolution over ages,
passing nearly intact through hundreds of millions of years of rising
and falling forms. These shared molecules and routines affect nearly
all the turnings of life, from birth and growth to perception and
This book is a pilgrimage to the heart of heredity. It is a
natural history not in the literal sense of a systematic inquiry, but
rather in the etymological sense, a telling of stories about life,
lineage, chance, and fate; about family, kin, and kind. It explores
both the projecting traits of the human family -- the one we’re born
into and the one we create -- and also the bigger, deeper inheritance
that ties us to the rest of life in profound, even shocking ways.
. . .
I like to hang around the doorway of biological surprise. For years I
have collected news of curious findings, of young spiders that eat
their mothers, of a giant fungus infecting miles of Michigan forest
spawned by a single spore in the last ice age, of fish with fingers,
caterpillars with lungs, genes with secrets. I don’t profess to
worship everything, but I do harbor strange sympathies fired by such
discoveries, a kind of naturalist’s faith. This is the news that
sweeps me away, the gnomic workings of the living order, nature’s
inventive jack-in-the-box surprises that shift our view of life like
the sudden twist of a kaleidoscope.
Here is an item from my files. When scientists deciphered the
intimate details of mating in yeast, that single-celled fungus that
raises our bread and brews our beer, they got a shock. The molecule
that draws two yeast cells into sex closely resembles one made by our
own brain cells to regulate reproduction.
The likeness seemed a fluke at first. But then other examples
popped out of the box: genes that shape the bodies of fruit flies so
like our own body-shaping Hox genes that one can put a human Hox gene
into a developing fruit fly embryo, and it will carry out the job of
the fly’s gene without a hitch; genes that shape the marvelous globe
of the human eye strangely similar to those that carve the compound
eye of a fruit fly; the tiny genetic mechanisms that drive our
biological rhythms, keeping us in tune with the big swings of night
and day, matching those in algae. So, too, do we share with other
organisms the ancient genes that dictate cell death, the phenomenon
that underlies metamorphosis, turning tadpoles into frogs and
caterpillars into butterflies and also shapes our bodies, whittling
away the webbing between fingers before birth, eliminating
inappropriate sexual organs. Common to all of us, as well, is a suite
of small, sturdy messenger molecules, offering clues to such
mysteries as why the cells of the human brain respond to the chemical
messages of the poppy plant and to the potent sexual attractants of a
Himalayan deer.
What are chemicals found in the human body doing in plants,
fungi, bacteria? How can genes that shape a fruit fly be near twins
of my own?
Disparate organisms, it seems, are more radically alike than
we ever imagined. Our deepest selves -- our very cells and molecules -
- are alive with reminders of old, enduring connections with other
creatures, resemblances that run right down to the root of the tree
of life. These items of shared inheritance have formed a library of
wonders in my mind’s eye. That there is a certain sameness among
life’s various forms follows from the notion that we all arose,
ultimately, from a common ancestor. We are shaped by fate, by what
came before. But life has chanced to venture in wildly different
directions. In learning to suck energy from sunlight and in
swallowing shocking amounts of oxygen, in heaving up from the
beneficent chemical crucible of the sea and in exploring leafy
interiors and desiccated desert, life has split into discrete
identities, strewn about fresh designs, unimaginably varied feet,
teeth, tongues, antennae, wings, leaves, brains.
In this world of dreamlike change, the lexicon of genes, like
human languages, is thought to evolve along unreturning tracks. We
know that nature is constantly making random changes in almost all
genes, and that two species that diverged from a common ancestor
hundreds of millions of years ago are likely to have accumulated a
lot of little alterations. As eons pass, so do variants of genes,
vanishing on the same wind that took the tyrannosaurs. It seems
strange and wonderful that among organisms so spirited with
individuality and detail -- pepper frog, salp, dragonfish, basset
hound -- there should be so much solid common ground.
Over the last few years I have wandered the body, looking for
these legacies and slim continuances, seeking to ferret them out of
their holes and sun them a little, to brush their surface in places,
give them a stab or pinch them to the bone if I could. I have tracked
the labyrinthine world of laboratories, too, asking about the
molecular bricks that underlie the splendid medley of living forms:
what makes them work so beautifully that they have demanded little
change in hundreds of millions of years? What happens if they go
awry? If organisms of such diverse stripes are made of similar genes,
how is newness born in the world?
By exploring this deep-down world, I hope to create new
shelves in my mind for the recent profusion of genetic discoveries,
the news of the sequencing of genomes from the tubercle bacillus to
Homo sapiens, the findings of genes linked with cancer, Alzheimer’s
disease, migraine, and baldness, passed down from father to son,
grandmother to granddaughter; genes affecting intelligence, sexual
preference, spatial ability, anxiety, sense of well-being -- some of
them discovered in small, so-called model organisms such as worms,
fruit flies, mice.
What is a gene, anyway? Are there genes “for” particular
traits? Are the letters DNA and RNA an Open Sesame to all the
familial secrets of life? Can we starve all of nature’s mysteries
into molecular oneness, explain the fruit solely by its root?
And what does one make of the notion that our genes mirror
those in yeast? Two decades ago scientists discovered that humans and
chimpanzees appear to have in common about 98 percent of their DNA.
Chimps are one thing, yeast is quite another. The news that, when it
comes to molecules, we are so perilously close to our tailed, finned,
and spoorish brethren goes against the stories I grew up on, biblical
tales of human supremacy and uniqueness, stories of how I
was “fearfully and wonderfully made,” as it is written in the Psalms,
to get up before the sun and buy a river, to buzz above all
creatures, “over the fish of the sea, over the fowl of the air, over
the cattle, over every creeping thing that creepeth upon the earth.”
Fear not therefore: ye are of more value than many sparrows.
(Luke 12:7)
We have for so long picked ourselves out from the horde of
other creatures, reckoned ourselves the peak and point of nature’s
whole history. What to do now, with this news of our deep-down
similarity, our profound kinship, with “lowly” organisms?
The physicist Michio Kaku once wrote that finding the key to
weather and seasons required a leap into another dimension, up into
outer space. Understanding humanity’s place in the matrix of life
requires just such a leap, but downward, into the diminutive world of
genes and cells.
Raised as I was on gerbils and birds, on the love of the
whole organism, not its microscopic parts, I find it a stretch to
descend into the darkness of a molecular world. I know my bats,
weasels, and wood frogs far better than I do the crabbed atoms of a
hemoglobin molecule. I am far more comfortable exploring the elements
of the violet family than those of the periodic table. The human mind
may have mastered the black hole and the quark, but most of us have
difficulty grasping the very big and the very small. We tend to think
easily only of things on our own scale, midway between the atom and
the sun. The first microscopists, confronted with the bizarre
creatures swimming beneath their lenses, sought desperately to see
bodies like their own, searched for sign of head or tail, denied as
long as they could the many orifices and multiple stomachs, the
brainless chunks of transparent flesh. So, too, we may seek in vain
the familiar in the minute parallel planet of genes and proteins.
To make things worse, the language of this world veers into
the cold domain of chemistry, where the common nouns are “nucleic
acids” and “amino acids”; the common verbs, “regulate,” “synthesize,”
and “catalyze.” One scientist grappling with the absence of a precise
definition for the term “gene” offered this to snarl the brain: “It
is the nucleotide sequence that stores the information which
specifies the order of the monomers in a final functional polypeptide
or RNA molecule, or set of closely related isoforms.”
But despite the dull terminology used to describe it, the
cosmos of molecules and cells has surprising beauties and minute
dramas every bit as beguiling as those of a bushmaster or a Bengal
tiger. In DNA, proteins, even in the molecules of water encapsulated
in our cells, are shapely details, beautiful clues that hold the key
to everything from the acuity of the eye to the memory of the immune
system. In their daily workings are tales of seduction, compromise,
duplicity, deception, stubbornness, art, magic, death.
I first learned of the Hox body-shaping genes when I was a
few months pregnant with my second child. The idea that the molecular
mechanisms shaping my baby’s growth were the same as those fashioning
the fruit fly I found oddly comforting. Think of all the bending and
breaking in the boughs of life. The notion that species as remotely
related as humans and flies are shaped by the same genes -- genes
that have slipped in and out of the Cambrian, the Devonian, the
Permian, the Pleistocene, requiring little revision in all that time -
- suggests that they must perform their task beautifully and will not
easily be wrenched off course.
Fish, fruit flies, wondrous babies: we may be a feast of
distinct entities, but we share the odd economies of nature from
birth to death. I’m thrilled to find that we’re connected with other
organisms, not by something as vague or slippery as animal nature,
but by a strong ribbon of measurable molecules, molecules so alike
that they can be swapped between species separated by half a billion
years of evolution.
I think our minds are built for the pleasure of discovering
likenesses or links between vastly different things. It is why we
delight in learning that the words “fate” and “symphony” share an
ancient root meaning “to speak”; that the opening of Beethoven’s
Fifth neatly repeats the call of the white-breasted wood wren; that
pointing a single finger to draw attention to something of interest
is bound tightly to the learning of language. (The earlier a baby
extends a demonstrative digit, the more words he or she will know by
the age of two.) It is why we love syzygies and rhymes and why we are
undone by Romeo’s words when he finds Juliet in the tomb and thinks
her dead: “Death hath suckt the honey of thy breath.” It is why we
believe Emerson when he tells us that “the world is a Dancer; it is a
Rosary; it is a Torrent; it is a Boat; a Mist; a Spider’s snare.”
The language of science holds a hunch here. Though some
scientific terms are Latinate and pompous, or simply weedy
(deoxyribonucleic acid, for instance, a great millipede of a term
that puts the mind off with its literalness), there are other terms --
pithy, germinal, long-lived, and prophetic -- that link the unlike
and suggest the blooming mysteries of both language and life. The
word “gene” goes back to an Indo-European root word that meant
beginning and birth. This gave rise to the Old English gecynd,
meaning family, kin, or kind. The Greek and Latin variants blossomed
into a bunch of gen words with a multitude of jobs: genus, genius,
gender, gentle, generous, generation, genealogy, genesis. One Latin
stem became gnatus, unfurling into innate, native, natural.
That so short and spare a word as “gene” would persist
through the revolutions of language and pop up in all these new,
masterful forms impresses me. So do these shared ancestral genes,
which are something like word roots. Knowing them is a way of prizing
what is essential in our common heritage. That we are still abob with
these ancient bits of biological wisdom, that they have endured over
eons in creatures as genealogically distant as worms and widowed
aunts, is to me as much a cause for celebration as a Bach cantata or
bird song.
These fragments of shared biology arose by chance and became
fate. I have come to think of them as points of entry or small
portholes through which to view the natural history of heredity. Or,
perhaps, like the scriptural mustard seed cast into the family
garden, from which one might draw radii to every corner of nature.
This book is a tracing of those radii. It is a journey in
four parts, starting with the roots of all flesh, the inherited
molecules that keep our bodies and those of other mortals alive and
thriving; then moving to the generation of our being as single,
sentient organisms, from our beginnings in sperm and egg -- those
seeds of inheritance -- to the birth of bodies with vision and the
capability of sex. Thence to our relations with other living things,
how we recognize, compete, and conspire with them in the deepest,
most intimate ways to make something more useful, more skillful, more
beautiful than what we might have made alone. And finally to our
common passage through time, from the immediate tick of the present,
by which our bodies stay in tune with the swing of sun and moon, to
our long passage out of the past, from earliest beginnings.

Why is it so strange and sweet to ponder a family tree? There’s the
chance to peer beyond one’s personal limits, to spot from the mast a
sea of unremembered relatives. Or to hunt up a lost connection with a
distant great-grandmother, to delve into the mystery of her existence
in her old home country. There’s the hope for pride of birth or
social credentials or a sense of rootedness, an antidote for those
plagued by mobility, by birdly migrations over one ocean or another,
between country and town, up or down the social ladder. Then there’s
the slim but tantalizing possibility of pecuniary gain in uncovering
a link with a relative of large estate -- though this is often a
mixed blessing, damnosa hereditas, the Roman jurist Gaius called it.
Come for your inheritance, says a Yiddish proverb, and you may have
to pay for the funeral.
In my own family tree, I’ve relished the weird weaving of
ancestral names -- Doerfler, Dresen, Homann, Huck, Koeppel, on one
side; Goldfarb, Dunkelmeyer, Blank, on the other -- names of dimly
recollected forebears who watched the skyline of New York from the
fourth-class deck of a steamer. I’ve also applauded the surprises in
my immediate family, the four girls defying the odds of sex ratio
and, especially, the exotic tendril of our fifth sister, Kim, adopted
by my parents from a Korean orphanage when she was four, whose own
biological roots remain a kind of Siberia.
Apart from satisfying a curiosity about one’s origins or a
yearning for old connections, apart from settling the matter of
estate, a practical use of genealogy is to sort out the hereditary
components of disease. When I was entering puberty, my mother took my
sisters and me to a genetic counselor to discuss our risk of bearing
defective babies. Ten years earlier my youngest sister, Beckie, had
come into the world with microcephaly and profound mental retardation.
Beckie had my mother’s slim build and dark hair, my father’s
brilliant blue eyes, and a brain so stunted that it would never allow
her to progress beyond a developmental age of six months. Beckie bore
witness to the curious dispensation of nature and gave me a kind of
fierce pride in differences. She made us love her from the start,
with her innocence wide open like water or air, her deep fondness for
music and peekaboo games, her sweet, easy affection and capacity for
passionate attachment, especially to my mother.
But imagine expecting another wonder baby and getting one
that couldn’t turn over, couldn’t find a nipple, who later couldn’t
crawl, babble, point an inquiring digit. When a lioness gives birth
to a defective cub, she slams it against the ground until it’s dead.
The experts advised institutionalizing Beckie. My mother, who had
recently pulled a child -- my sister Kim -- out of one institution,
could not accept the idea of putting this child into another.
Generous to the bone, she could not but treat Beckie tenderly,
carefully, equally, as her own, with honor.
Our extended family -- grandmothers, cousins, uncles -- felt
as Gregor Samsa’s family did in Kafka’s Metamorphosis. When one
morning Gregor was transformed into a cockroach, his family reassured
itself again and again that “things will be fine, that he will come
back to us.” Surely our family could find the quick fix, the turning
of some deep chemical key that would bring Beckie back to normal, the
swift knock to the special lobe or zone in her skull that would cause
a little cerebral explosion of nova-like growth to set things right.
We knew better. Beckie was the hatchling of our new reality.
To some of us she gave a bright, burning belief in the sanctity of
life; to others, a smoldering point of shame or resentment, stoked by
the deep fear that we, too, might one day bear such a changeling.
Doctors had ruled out as possible causes of Beckie’s
deformities alcohol, drugs, exposure to lead, Down’s syndrome, brain
damage from insufficient oxygen or cerebral bleeding during birth. My
mother now hoped to rule out any play of heredity.

In the sixteenth century, Michel de Montaigne counted heredity “among
the wonders so incomprehensible that they surpassed even miracles in
What a prodigy it is that the drop of seed from which we are produced
bears in itself the impressions not only of the bodily form but of
the thoughts and inclinations of our fathers. Where does that drop of
fluid lodge this infinite number of forms? And how do they convey
these resemblances with so heedless and irregular a course that the
great-grandson will correspond to his great-grandfather, the nephew
to the uncle?
In one Roman family, he observed, “there were three, not in a row but
at intervals, who were born with the same eye covered with cartilage.
At Thebes there was a family that from their mother’s womb bore the
figure of a lance-head, and whoever did not bear it was considered
illegitimate.” Montaigne believed that he himself had inherited from
his father that “stony propensity,” the painful curse of gallstones.
He puzzled over how his father, who had first begun to suffer from
gallstones twenty-five years after his son was born, could have
transmitted to his offspring something he did not possess when the
son was conceived.
Where was the propensity to this infirmity hatching all this time?
And . . . how did this slight bit of his substance, with which he
made me, bear so great an impression of it for its share? And
moreover, how did it remain so concealed that I began to feel it
forty-five years later, the only one to this hour out of so many
brothers and sisters, and all of the same mother?

In preparation for the genetic counseling, I puzzled over charts of
traits dominant and recessive, diagrams of red- and white-eyed flies
and of the smooth and dimpled peas that illustrated Gregor Mendel’s
brilliant insights into genetic dominance and the segregation of
traits. Before Mendel, heredity was thought to be transmitted as a
kind of solution in blood, parental bloods being mixed in the child --
a belief carried forth in language: half-blood, pure-blood, blood
will tell.
Mendel suggested that hereditary information was a matter not
of solution or alloy but of individual units, or characters. Trained
in physics, the Austrian monk proposed in 1865 that traits were
passed along family lines from parent to offspring in discrete
elements, called “factors” (later renamed “genes” by a Danish
geneticist). Different factors controlled different traits or aspects
of appearance, say, pea color or shape. These factors occurred in
pairs, one member of the pair contributed by each parent. The two
factors might carry conflicting instructions, in which case the voice
of one would dominate. But the other would linger in recessive form,
possibly to be rekindled in later generations.
I imagined my own family’s marks mixing up and falling out in
the neat patterns of Mendel’s peas. Facial characteristics recurred
in our clan -- the Germanic nose with a long swoop and a soft,
upturned tip, the multiple moles, the gray-blue eyes dutifully
delivered to all four girls. Also, I believed, a tendency to
impatience, a love of fresh air and exercise.
But I have since learned that there are brambles along this
path. Much heredity does not follow the patterns set down by Mendel.
Complex traits, especially aspects of intelligence and behavior,
arise not from single genes but from the play of many genes and their
environment, both within the body and outside it. Even eye color is
more complex than we once imagined, a so-called polygenic trait. The
early view that blue eye color is a simple recessive trait has been
upended by the brown-eyed offspring of two blue-eyed parents.
Polygenic or not, some characteristics clearly do run in
When I’m in a mood, suffering from a bout of hay fever or
chilblains that keeps me indoors, I like to page through Victor
McKusick’s Mendelian Inheritance in Man, a two-thousand-page
catalogue of every hereditary trait known: dominant, recessive, X-
linked. Though the list is now available in a thoroughly modern, up-
to-date computerized version, I prefer to thumb the older paper
volume for discussions of such traits as:
the ability to move one’s ears, “in males sometimes associated with
the ability to smell androstenone
modification of taste by artichoke, wherein eating an artichoke makes
water taste sweet
motion sickness
male pattern baldness
the whorl in scalp hair
Facial features do tend to crop up in one generation after another,
like the large dark mole on the forehead of my brother-in-law, which
his wife insisted he have surgically removed, only to find a nearly
perfect copy on the forehead of her newborn son. Or those most famous
of facial resemblances, the Bourbon nose of the royal houses of
Europe and the Hapsburg mouth, that underslung lower lip that showed
up century after century in the rulers of Austria and Spain.
In McKusick’s catalogue are also rare “mutant” traits that
run in families -- hairy ears, elbows, nose tip, palms; cherubism, a
swelling of the lower face around the third or fourth year of life;
distichiasis, or two rows of eyelashes; absence of fingerprints --
all reminders that we call contrary to nature what happens contrary
to custom. Also listed are mutated genes linked to the susceptibility
to rare diseases: acromelalgia (or hereditary restless legs),
trembling chin, Tay-Sachs disease, sickle-cell anemia, thalassemia,
cystic fibrosis.
Fifty years ago, Linus Pauling showed that the key to innate
susceptibility to disease could be traced to an alteration in the
molecular structure of a protein, which was, in turn, caused by a
defective gene that could be passed right on down the familial line.
In this way, a Canadian woman born in 1824 who was affected with
aniridia -- a defect in a gene that shapes the eye -- generated the
ailment in whole limbs of her large family tree, with seventy-seven
of her descendants suffering from visual handicaps.
Findings of such “disease” genes most often come from studies
of families. A gene implicated in dyslexia was unearthed in a study
of a large Norwegian family in which eleven of thirty-six members had
the disorder. Through such family studies, a gene that contributes to
disease susceptibility may be traced to a location on a specific
chromosome. The DCP gene, for instance, implicated in myocardial
infarction, resides on Chromosome 17. So does the MPO gene, villain
in yeast infections, as well as the MAPT gene, linked with dementia,
and BRCA1, tied to breast cancer. But to “inherit” the susceptibility
to myocardial infarction or dementia is only to hold the gene or set
of genes that gives one the potential to develop heart disease or
madness -- just as to inherit genes for perfect pitch or curly locks
is to harbor the potential for musical talent or Milton’s “wanton
Like most families, mine carries genes linked to common
ailments, such as asthma, thyroid trouble, and my own triad of minor
ills -- ragweed sensitivity, hemiplagic migraine, and Raynaud’s
disease, or hereditary cold fingers.
But mental retardation?
Beckie’s disabilities might have wormed their way into her
genome on a sly recessive gene. McKusick lists seven different
syndromes of microcephaly linked with recessive genes, including true
microcephaly (which in one family cropped up in four of the nine
children born of first-cousin parents). Or they might have come from
mutations on an X chromosome. Fragile X syndrome, the most common
inherited form of mental retardation, arises from a mutation in one
end of the so-called FMR1 gene on the X chromosome, a strange stammer
of DNA that results in faulty brain development.
Finding a possible hereditary link meant going deep into
family history, searching out the branches and twigs of the extended
family tree. This was not an easy undertaking in my clan, which
possessed no willing elderly remembrancer. My mother’s mother had
once constructed a webby little pedigree, peppered with holes and
festooned with looping curlicues and odd little familial spirals. My
father’s mother steadfastly refused any such dig into her background
and, when begged for a quick pedigree sketch from her memory,
produced a crude little shrub topped -- only half-jokingly, she said -
- with Abraham X, horse thief, and his brother Isaac, rapist. The
granddaughter would remember what the daughter would forget.
We did unearth a cousin with mild mental retardation, but so
radically different was his disability from my sister’s, and so
distantly related was he to my mother, that there was little possible
genetic connection. Beckie’s microcephaly might have been produced by
her in utero exposure to X-rays, the experts said, or, more likely,
to a virus. They agreed that my chances of having a child like Beckie
were about the same as my neighbor’s.
But I wondered about the twigs of disability that might lie
hidden among our family limbs. Every genealogical tree has its holes,
its secret boughs and branches, the upshot of poor records or
unspoken rules about keeping mute on family trouble. Imagine the
leaves that might quietly wilt away from official family history --
the secret liaisons, discreet separations, the bachelor or spinster
howling from some moldy, worm-eaten limb, the wayward running weed
that started a secret new offshoot.
The farther back we go, the less we know. Most pedigrees are
haunted by tender ghosts of forgotten forebears who are recalled, if
at all, as faint mysteries limned in thin anecdotes or brown photos.
Still, when one looks at any genealogical spruce or yew, however
patchy or lopped, it’s pleasing to consider that each of us is
fastened to a long string of ancestors -- unknown and unknowable in
the flesh, perhaps, but faithfully recalled in stuttering voice in
our own genomes.

I don’t know when I first became aware of science’s efforts to weave
all the world’s organisms into a great family tree, systematically
relating one thing to another by way of likeness. I do remember
learning from my older sister the neat trick of spotting families of
flowers through common characteristics. The crucifers -- cabbage,
turnip, radish -- have a slender seedpod and four petals that form a
cross. A violet you can tell by its five petals (the two lateral ones
bearded), and by its pistil, shaped like a short beak. Through the
mint family, Labiatae, run two flaring lips, square stems, and a
distinctive aroma.
When I was twelve or thirteen, my father taught me the Latin
binomials for common species of birds: Dendroica pinus, Dendroica
discolor, Sitta carolinensis, Sitta pusilla. We rose in the early
morning to watch birds together, moving quietly in late starlight.
Small sounds would hatch from the foliage, not just the normal
morning short calls, the hoots, squawks, jargles, whistles, and
rasps, but clear strands of real music that seemed to be sung for
joy. If luck was with us, we would be jogged awake by the thin
fluting notes of a goldfinch or the chromatic cry of a whitethroat.
(Later I would learn the surprising fact that stripe-backed wrens so
systematically pass their vocalizations down from father to son and
from mother to daughter, like a beloved heirloom, that their songs
are a highly reliable way of determining family ties.)
Most bird families were a joy to learn: the three little
titmice, Paridae; three nuthatches, Sittadae; six swallows,
Hirundinidae; seven woodpeckers, Picidae. I loved finding that I
could join two birds and see in them one nature; then three birds;
then twelve, the faint tracings of individual species converging into
major family paths. I remember how the discovery that the natural
world had been classified and given two-part scientific names --
names that were, in fact, a way of weaving creatures together by
natural principles of likeness -- shot through me like a bolt of
In the eighteenth century Linnaeus arranged living things in
a pattern based on these principles (and freely admitted to being the
one chosen to do so, the one whom “God has suffered . . . to peep
into his secret cabinet”). I grew to love the Linnaean system, the
great animal and botanical divisions, the tidy nests within nests,
all the shreds of creation revealed and broken down into pieces, then
stitched back together in a great familial tree.
Charles Darwin gave ground for the view that the likenesses
Linnaeus observed were quite literally family likenesses, that
individual species were netted together by threads of ancestry. As he
wrote in Origin of Species: “All living things have much in common,
in their chemical composition, their germinal vesicles, their
cellular structure, and their laws of growth and reproduction.” In
the book’s only illustration, Darwin showed variants within a species
as branches of a tree. He later explained that the “limbs divided
into great branches . . . were themselves once, when the tree was
small, budding twigs.” All modern species diverged from a set of
ancestors, which themselves had evolved from still fewer ancestors,
going back to the beginning of life. The relations among all could be
represented as a single great dendritic tree.

Darwin himself was heir to assorted intuitions on the kinship of
living things. In 1793 William Blake wrote:
Am not I
A fly like thee?
Or art not thou
A man like me?
A drawing made by Blake the same year shows a caterpillar on a leaf
arched over a lower leaf, on which reclines a second simple,
cocoonlike form, this one with the face of a baby. The drawing is
titled What Is Man?
John Clare called flies “the small or dwarfish portion of our
own family.” That was in 1837, just before the English nature poet
was declared insane and committed to an asylum.
“It seems that Nature has taken pleasure in varying the same
mechanism in an infinity of different ways,” wrote the eighteenth-
century French philosopher Denis Diderot. “She abandons one type of
product only after having multiplied individuals in all possible
Diderot’s contemporary, the naturalist Georges Louis Leclerc,
Comte de Buffon, came close to anticipating Darwin. He wrote, “It may
be assumed that all animals arise from a single form of life which in
the course of time produced the rest by process of perfection and
degeneration.” A single plan of organization could be traced back
from man through fish, said Buffon in his encyclopedic Histoire
naturelle. (Buffon, who aimed to describe the whole of the natural
world in fifty volumes, was so obsessed with his subject, the tale
goes, that he evoked from one Madame du Deffand this remark: “He
concerns himself with animals; he must be something of one himself to
be so devoted to such an occupation.”)
Richard Owen, a quick-witted and prescient British anatomist,
made detailed observations of the unities underlying life’s wild rage
of differences. The wing of the bird, fin of the fish, hand of man,
he wrote in 1848, were all built according to a single design.
These “homologies” were of far greater importance in the scheme of
God’s grand plan than the minor adaptations that distinguished the
organ of one creature from that of the next.
The mind must embrace the whole and deduce a general type
from it, wrote Goethe. The German polymath, whose interest in unity
grew out of the terrible divisions of his age, possessed the rare
ability to leap from science to poetry and back, and -- when he was
not writing literature -- did important work in anatomy, botany, and
geology, coined the term “morphology,” and even managed to discover a
new bone in the human upper jaw. Goethe wrote that all individual
organisms have universal tendencies, to transform themselves, to
expand and contract, to divide and unite, to arise and vanish, and he
claimed to have traced “the manifold specific phenomena in the
magnificent garden of the universe back to one simple general

After Darwin, natural historians saw the reconstruction of life’s
tree as their most important task, scrutinizing the details of shape
in adult animals and embryos, the number of rays in a fin, of rows in
scales, to deduce the degree of relation. From these, they drew up
careful family descriptions, leaving little doubt that fish,
amphibians, reptiles, birds, and mammals all descended from a common
ancestor. But it would take another century, and a bevy of bright,
restless scientists with minds full of physics and with pluck on
their side, to unmask the molecular likeness at the heart of life.
Strung through all organisms was a single genetic thread made of the
same molecular stitches. The difference between a bacterium and a
bullfrog lay largely in the order and the sequence of those stitches
as well as their total number.
So it was true. The whole code of nature could be written on
a thumbnail. Compound it how you will, salamander, German
philosopher, algal mat, ginkgo tree, it is but one stuff, the eye of
the needle through which all life passes. “Nature uses only the
longest threads to weave her patterns,” wrote the late physicist
Richard Feynman, “so each small piece of her fabric reveals the
organization of the entire tapestry.”
The findings of the last few decades have made this fact more
urgent. Among the genes for tune deafness and hairy palms in
McKusick’s masterly catalogue are genes for the making of cytochrome
C, crystallin, ubiquitin, Hox proteins, and other useful molecules,
found not just in members of the human family but in nearly all
organisms: worm, ladybird, siskin. When scientists learned to read
genes and compare them in separate organisms, their really big shock
came on finding the easy way genes from vastly different creatures
fell into families, with sequences of stitches so similar that they
had to be of common ancestry. These small shared sequences were like
family earmarks as distinctive as the square stem of the mint family
or the Hapsburg lip.
If a gene has endured almost intact for millions of years in
so diverse a panoply of creatures, it likely serves a vital purpose;
disable that gene, and the consequences may be catastrophic.
Scientists recently scratched around in the yeast genome for
sequences like those in certain human genes that, when mutated, are
known to cause disease. They found that one in four of these human
genes matched a yeast gene, including one involved in cystic
fibrosis. And listen to this, William Blake and John Clare: of the
289 known human “disease” genes, 177 have direct counterparts in the
fruit fly. (This is good news for research on disease. When
scientists find a gene in a worm or a fly that matches a human gene,
they can study that gene and its function more easily in the simpler
organism than they can in humans, whose genomes are much more
Accepted wisdom had it that genes were unique and
idiosyncratic, peculiar to particular species. But now it seems that
many are close relatives in one degree or another, belonging to one
of a few thousand families. Genes shared by the widest range of
organisms are probably modern versions of life’s oldest genes.
Suddenly it’s possible for scientists to draw up life’s evolutionary
tree, to sort out the relations among modern creatures and their
distant ancestors, not on the loose basis of appearance -- the shapes
of leaves and fins, the color of feathers, which are often deceptive -
- but with tight molecular precision. By drawing the family trees of
genes in modern forms of life and running them backward to the genes
at the root of the tree, they may even define the nature of the
universal ancestor from which all life sprang.
Here is a lesson from the gene-based tree: Life comes in
three basic forms -- archaea, bacteria, eukaryotes. Organisms made of
one cell constitute the majority of life forms, fully occupying two
of these three great trunks; we animals are but a slim sprig
sprouting from the third. And another lesson: fungi -- the broad
category embracing mushrooms, molds, and yeast, lumped with the
vegetable since Aristotle -- are more like animals than plants,
sharing more genetic ground with man than with moss or peach tree.
(These close relations account for the difficulty of treating fungal
infections in humans. So similar are our biochemical pathways that
what kills fungal cells tends to harm human cells, too.) The tree of
life is looking less like a tidy branching of lily and lichen, fly
and dandelion, and more like a thicket, like my grandmother’s webby
family tree, with more tightly linked ties and binds than we ever

If unearthing connections with long-forgotten great-grandparents
fills one with sweet satisfaction, think of the promise of deeper
probing, of uncovering the roots of oneself in deep-lying, distant
ancestors of the family -- shrew, fish, amphioxus -- right down to
our oldest, most innovative forebear: the inventor of our brilliant
little genetic thread.

Copyright © 2001 by Jennifer G. Ackerman

What People are Saying About This

Jonathan Weiner
Chance in the House of Fate is about the biggest biology story of the last ten years: the discovery of remarkable family resemblances that unite every living thing in the tree of life, at the level of our genes. It's a beautiful discovery that has accumulated bit by bit in thousands of laboratories all over the world. Jennifer Ackerman has risen to the occasion with a beautiful meditation on our likenesses, like a poet musing in the small hours after a family reunion.
— (Jonathan Weiner, author of The Beak of the Finch)
Alan Lightman
Chance in the House of Fate is a poet's embrace of the biological world, written with grace and intelligence, warmed by a personal story. I am reminded of Lewis Thomas and Annie Dillard, but most of all of Walt Whitman, Jennifer Ackerman sings a song of self in the widest possible sense, the unity of all life on our planet.
— (Alan Lightman, author of Einstein's Dreams and The Diagnosis)

Meet the Author

Jennifer Ackerman is a writer specializing in the sciences. Born in 1959, she was educated at Yale College, where she studied literature, graduating cum laude in 1980 with a BA in English. Jennifer Ackerman began writing full-time in 1989. Ackerman's first book, Notes from the Shore (Viking, 1995), describes the nature life of the mid-Atlantic region. Edward Hoagland called the book"the alchemy of art with solid science." The Washington Post described it as"arresting and provocative, a joy to read." A paperback edition of Notes from the Shore was published by Penguin in the spring of 1996; an Italian edition is forthcoming from Ugo Guanda Editore. Ackerman won an Established Artist Fellowship from the Delaware Arts Council for her work on the book. A contributing writer and editor for The New York Times, National Geographic Magazine, and many other publications, Ackerman has written essays and articles on subjects ranging from the nature and politics of barrier islands to the origin of brids, parasites as agents of evolutionary change, and the work of Nobel prizewinning developmental biologist Christiane Nusslein-Volhard. Her writing has been collected in several literary anthologies, among the The Nature Reader, eds. Daniel Halpern and Dan Frank (Ecco, 1996), Best Nature Writing(Sierra Club, 1996), From the Field (National Geographic Society, 1997), and The Beach Book: A Literary Companion (Sarabande, 1999). Ackerman is married to novelist Karl Ackerman and has two daughters.

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