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Elof Carlson

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By Elof Axel Carlson

In preparation for his work on evolution by natural selection, Charles Darwin in the 1850s studied where domesticated animals came from. He went to hobby shows and looked at pigeons in particular to see where they originated. He claimed all the varieties stemmed from one species, the rock pigeon, Colomba livia. Today that origin is known in more detail, with domesticated pigeons described in both Sumerian and Egyptian writings some 5,000 years ago.

An actual effort to look for centers of origin of plants was made by the Russian botanist and geneticist, Nicolai Vavilov (1887–1943). He proposed five (later extended to eight) centers of origins for cultivated plants. To do this he organized over 100 expeditions that he and his students took to Central and Southeast Asia, the Americas, the Middle East, Eastern Europe and North Africa.

In your salad there might be lettuce (Mediterranean), tomato (South America), pepper (South America) and spinach (Central Asia). Your vegetables might include carrots (Central Asia), asparagus (Mediterranean) and maize (South America). For dessert you might enjoy bananas (Indo-Malaysian), apricots (Middle East) and oranges (India). Your cereals might include barley (Near East), wheat (Central Asia), oats (Mediterranean) and rice (Far East).

Humans did most of their domestication of foods from wild ancestors between 5,000 and 15,000 years ago. They shifted from hunting and gathering to farming and used selection to save the seeds of their favored plants and bred their favored animals to produce the hundreds of varieties of living things that clothed them, amused them, protected them and fed them. It was not until the 20th century that the genetics behind the selection process was understood and could be used (especially in agriculture schools) to accelerate the number of varieties of food that we see in a supermarket.

Vavilov became the equivalent of the secretary of agriculture in the USSR and collected 375,000 varieties of seeds that he housed in Leningrad (now Saint Petersburg). During the siege of Leningrad in World War II, those seeds were protected although several of those protecting them died of starvation.

Vavilov was arrested in 1940 by his foes who did not accept genetics on ideological grounds and he died in Saratov prison. After Stalin’s death, his critics were deposed and Vavilov’s reputation was revived and his home institute was renamed in his honor.

Vavilov was the founder of the first seed bank, and that model became the basis for the first gene bank during the era of molecular genetics and genome sequencing in the late 20th century.

Today the study of the genomes of agricultural plants is a thriving field with the ancestry of each animal or plant type worked out in exquisite detail. It allows geneticists to create new varieties to meet the needs of different environments.

Elof Axel Carlson is a distinguished teaching professor emeritus in the Dept. of Biochemistry and Cell Biology at Stony Brook University.

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By Elof Axel Carlson

Most scientists consider themselves reductionists. The term suggests that complex things can be analyzed to simpler components. A molecule of water can be “reduced” to two hydrogen atoms and one oxygen atom. Sunlight, when using a prism, can be reduced to a spectrum of rainbow colors. Our body can be reduced to organs, tissues and organelles. A star is a ball of mostly hydrogen atoms whose mass generates such heat and pressure that some of its innermost atoms are fused, producing immense heat, ultraviolet radiation, gamma radiation, light and the formation of new elements. A galaxy is a rotating pinwheel of billions of stars.

At the same time, many scientists recognize that there are ever-changing systems. We think of ourselves changing from a fertilized egg, a ball of cells leaving the oviduct and entering the uterus, a differentiating implanted embryo forming tissues and organs, a fetus making its presence known by its movements in an amniotic sac, a newborn baby, a dependent infant, a toddler, a child actively learning, an adolescent in high school or college, a young adult, a middle-aged adult, an old person and eventually a corpse to be buried or cremated.

Along with a changing physical state in our life cycle, we are aware of how our personalities changed (or stayed constant) and the hundreds of influences from our parents, siblings, neighbors, schoolmates, teachers and hosts of encounters from whom we meet, what we read and what we observe. We recognize ourselves as being rational, emotional, spiritual, idealistic, competent, insecure, inspired, depressed, self-serving, altruistic, generous, greedy and a variety of other (often contradictory) ways. Analyzing who we are, as functioning persons or societies, is harder than identifying our physical components. That is also true for ecosystems or the associations that participate in a community whether it is a forest, grassland, tide-pool, lake or river.

Analyzing who we are, as functioning persons or societies, is harder than identifying our physical components.

Alexander Humboldt was the first to see the universe (he called it the cosmos) as a connected system. Everything is connected to everything and it constantly changes. Philosophers call this outlook “holism.”

Humboldt’s holism was systematic, and as he climbed up mountains he took notes on the plants and animals (preserving samples for later study) and chipped off minerals as he noted the changing rock formations during his ascent. He noted how temperature dropped as he climbed upward. He used instruments to measure the air pressure. The field he founded was ecology, although it would be more than 50 years later that it got its name.

In contrast to Humboldt, other scientists saw holism as a way to merge science and religion. Thus Goethe saw a spirituality in the study of the cosmos, and German scientists embraced his “nature philosophy” approach. In the United States Emerson extended holism to the universe, which he described as an “oversoul.” It launched his Transcendental movement. Still others invoked “vital spirits” or a life force that animated all living things and that disappeared when they died.

I much prefer Humboldt’s approach to those holists who invoke a supernatural aspect to complexity. If processes and things are claimed to be beyond the reach of science, then our understanding of complex things is limited. At the same time, it is naive to claim that everything is possible, such as perpetual motion, living forever, or willing oneself (unassisted) to run as fast as the speed of sound. Scientist cannot ignore the complexity of the things they study but neither should they be paralyzed into inaction because of it. Humboldt’s approach is both reductionist and holistic, and it served him and society well by enriching our understanding of how the universe works.

Elof Axel Carlson is a distinguished teaching professor emeritus in the Department of Biochemistry and Cell Biology at Stony Brook University.

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By Elof Axel Carlson

I learned from my daughter-in-law, Dawn Allen Carlson, that my son John died as he was recovering at home from pneumonia treated with antibiotics. John (1962-2016) could not be revived by the EMT or after being taken to the hospital in Swampscott, Massachusetts, where he lived.

John was a happy child and had many friends at Ward Melville High School. He went to Yale for his bachelor’s degree and loved volleyball, serving as captain of his team. He switched from engineering to mathematics and got his master’s in applied mathematics at Stony Brook University.

John loved history and read widely. He treasured the Civil War narrative histories that he inherited from my brother Roland. I had seen John last at the memorial service for my daughter Claudia. After I finished my presentation on the stage of the Hotel Roger Smith in Manhattan, my son John scooped me off the high platform and gently brought me down to the floor.

John used his skills as an actuary and as a designer of computer software for corporate health and retirement programs. When he was a child, I marveled at his gift for playing Monopoly, where instead of counting out each spot for landing a marker, he just lifted it from the board and placed it where it should be. He was invariably the banker for the game. John was gentle in his personality. During Claudia’s last month of life, he helped move in a hospital bed and rearrange her furniture so she could see people who came by.

I have learned that the hardest psychological impact of aging is being alive to see family members, students and friends younger than me die. It is so unfair that Claudia will not experience holding a grandchild and John will not experience the weddings for his two adult children. But this is characteristic of life. It does not abide by our wishes or logic.

While I know this from my immersion in the life sciences, the injustice of it is hard to rationalize by science or faith. I can hear John’s resonant baritone voice in my head and savor the rational, sympathetic way he handled crises. I shall miss his telephone calls and the delight of discussing history and current events with him filled with wit and insight.

Elof Axel Carlson is a distinguished teaching professor emeritus in the Department of Biochemistry and Cell Biology at Stony Brook University.

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By Elof Carlson

In 1907 a graduate student at Columbia University, Fernandus Payne, did a project supervised by his mentor, T.H. Morgan. He spent two years growing fruit flies in the dark. That’s 69 generations of fruit flies (or about 1,500 years if it were done on humans). Payne tested samples every 10 generations and found there was no change in eye color, a robust red, and there was no change in the flies’  attraction to light. They moved toward light.

In 1954 at Kyoto University, Syuti Mori placed some fruit flies in darkened containers and they have been bred and raised in the dark ever since. That’s about 1,500 generations (in humans it would be about 40,000 years in the dark).   

Mori wondered what changes would take place in the dark that would differ from the original control flies from which they were separated. He and his colleagues found that there were changes. The flies developed larger bristles (which can detect contact with objects and sense what they are) and they developed a greater sensitivity to hormones that are released as sex attractants.

Mori is now retired, but his colleagues continue to follow the new generations raised in the dark. They found 84 differences in their genes and they have already detected those affecting the bristles and those affecting sex hormone production and detection. Each gene difference is being isolated and its function is being worked out. They hope eventually to identify those genes that are random events that have no role in the adaptation to living in the dark and those that do have a role to play in living in the dark. They also hope, when the project is completed, to copy the appropriate mutations and insert them into control flies not raised in the dark, to see if these altered flies are as efficient as the 1,500th generation flies living in the dark.

This would be a nice contribution to the analysis of an evolutionary process because it would show the molecular basis for the differences between the two adaptive strains (one by selection and the other by genetic engineering) and how they differ from flies not grown in the dark.

Long-term experiments are relatively rare in science, especially those that are continued after the retirement or death of the original investigator. Both Payne’s experiment, more than a century ago, and Mori’s, which is ongoing, show how science is limited by what it knows and by what tools are available to advance our understanding.

In 1907 Morgan and his students had not yet worked out X-linked inheritance, mapping genes or determined mutation frequency. That genes were composed of DNA was not demonstrated until 1944. That DNA provided a mechanism for how mutations arise was not worked out until the late 1950s. Working out complete genomes of multicelled organisms did not occur until the 1990s. Inserting genes to specific places in the chromosomes was not possible until this decade. The experiments that can be done today were impossible even to imagine 100 years ago.

Elof Axel Carlson is a distinguished teaching professor emeritus in the Department of Biochemistry and Cell Biology at Stony Brook University.

The oldest known man in the world, Jiroemon Kimura. File photo

By Elof Carlson

The oldest authenticated woman was Jeanne Calment (1875-1997), which made her 122 years old when she died in Arles, France. The oldest authenticated man was Jiroemon Kimura (1897-2013), who lived 116 years and 54 days and died near Kyoto in Japan. That is in keeping with the finding that in all cultures women live two to five years longer than men.

This might be genetic (males are XY; so any harmful genes on the X are expressed in them) or it might be because males have usually done more dangerous work exposing them to carcinogens and mutagens or they tend to abuse their bodies more than women do with tobacco and alcohol. Both factors may play a role.

Mean life expectancy is a measure used by those who tabulate vital statistics. It is usually done on the day of one’s birth. It includes all deaths at any age. This creates a misleading number. Thus the mean life expectancy in the Stone Age when many of our ancestors lived in caves was about 20. This low number is based on studies of skeletal remains in these caves. In one study of 4000-year-old skeletons in the Orkneys just off northern Scotland, out of 342 skeletons, 63 died as teens, 24 died as toddlers, 70 died as children (2 to 12 years old), and 185 were adults (20 and older).  Many of the adults lived to their 50s.

The oldest known woman in the world, Jeanne Calment. File photo
The oldest known woman in the world, Jeanne Calment. File photo

Infant skeletons are underrepresented because they are least likely to be preserved. Infant mortality was common during all civilizations until the germ theory was introduced and the transport of foods in the last half of the nineteenth century reduced both infections (pneumonia and gastritis) and malnutrition, which were the major causes of infant mortality. Half of all children died in their first year for most of the history of humanity.

Today, virtually all of the children born in industrialized countries live to reach reproductive maturity. Even in the 20th century, these reductions in infant mortality are apparent: they were 10 percent of U.S. births in 1907, 2.6 percent in 1957 and 0.68 percent in 2007. The mean life expectancy for U.S. males was 45.6 in 1907, 66.4 for 1957 and 75.5 in 2007.   If one excludes infant mortality, there is still a better chance today of a person of 50 living to be 80 than it was in 1907, but the dramatic decline in death has been in childhood infectious diseases.

We owe that triumph to public health — especially the pasteurization of milk for infants and the use of chlorine in reservoirs to kill typhoid and other bacterial agents in drinking water.

Very likely by the end of this century most babies will have a mean life expectancy of about 90 (for females) or 87 (for males). The five-year gap between males and females is also narrowing, but at a slower rate.

While there are many attempts through diet and food supplements to extend life, the more likely outcome has been to have more people who live into their 80s and 90s. Centenarians are still relatively rare in industrialized nations. No one knows what makes a person live to 110 or more years (so rare that they are news stories when they die).

When my wife Nedra’s second cousin Grover Dawald (1884-1990), had his 105th birthday in Rochester, Indiana, he received a card of Congratulations from President George H. W. Bush. He was still living at home and danced on the day of his last birthday.

Elof Axel Carlson is a distinguished teaching professor emeritus in the Department of Biochemistry and Cell Biology at Stony Brook University.

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By Elof Carlson


My mother was a paranoid schizophrenic.

She had been married before in a traditional Jewish arranged marriage to her father’s business acquaintance. He told his daughter, “Ida, this is Max. He will be your husband.” She had two children with her husband, my half-brother Ben and my half-sister Sadie. The marriage failed and eventually they separated, and the children were placed in a Hebrew orphan asylum in New York City.

My mother tried to get her children back, but when she stormed the desk of a charity worker she was instead committed as insane to Pilgrim State Hospital. After three months she was released, and one winter day in Manhattan as she sold key rings on the streets, she tried to warm up in a hotel lobby. The doorman told her to warm up downstairs in the employee’s room. There she met my father, a Swedish-born, lapsed Lutheran,  merchant mariner who settled in New York City. He took her to dinner and they began a courtship.

Max obtained a divorce and my parents were married in New Jersey. A year later, my brother Roland was born and a year and a half later, in 1931, I was born.

I began to realize my mother was different when I was about 5 years old.  She would get hysterical. She had fights with our father. When she got angry at our behavior, she would smash dishes on the floor and we would scoot under the bed. I got used to meals left half-eaten at restaurants or movies whose ending I did not get to see when she would leave, because she thought people were staring at her or talking about her.

But I also realized she was very protective. My brother was born with a congenital heart condition. She made sure he did not exert himself and took us to the parks to play rather than to play with neighborhood children. She took us to art shops and museums, or cooled us off during heat waves by going back and forth on the Staten Island Ferry.

She took us to bookstores and shared with our father, an elevator operator, the importance of learning and the arts. Every day she would take her violin and play for us for an hour, especially the music of Stephen Foster, Fritz Kreisler and other light classical selections. When we were teenagers, she began going out in the evening and playing as a street musician.

I think my father stayed in a bad marriage because he did not want to see his two children also ending up in an orphan asylum or foster home.

I learned from my mother that she was not insane all the time. She had her good days and I never doubted her love for us. She encouraged our efforts at art and praised our passion for reading. I also admired her ability to do a lot with very little money.

She liked to visit her daughter in California and would get a one-way ticket by train, get off during a rest stop, play her violin for donations from passengers and continue on until she got to California. She only took a sneaker bag for her clothes and her violin case as luggage. It taught me how creative I could be when I lacked the traditional ways to do things.

When I was at Tougaloo College teaching in an all-black school, I found the library had no books or journals on human genetics. So I called the medical school in Jackson, Mississippi, and arranged to bring four students at a time in my car to its library. I taught the students how to use the “Index Medicus” to select articles. We read together taking notes at the library table. I learned about my students’ lives during the car trip to or back from the library.

I would not have improvised had it not been what I learned from my mother.

Elof Axel Carlson is a distinguished teaching professor emeritus in the Department of Biochemistry and Cell Biology at Stony Brook University.

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By Elof Carlson

My daughter, Claudia Carlson, died Jan. 6, at the Dawn Greene Hospice in Manhattan, after a two-year battle with ovarian cancer. She attended Ward Melville High School in Setauket and Stony Brook University.

Claudia was born in Bloomington, Indiana, when I was a graduate student at Indiana University. I was married to Helen (nee Zuckerman) Carlson, whom I had met at NYU when we were undergraduates. The marriage failed a year after Claudia was born and Claudia was raised in seven college towns, where Helen taught in English Departments.

I visited Claudia on holidays and when she turned five, she spent her summers with her new family, after I married Nedra (nee Miller) Carlson. She joined us permanently after her mother was diagnosed with lung cancer, at the age of 42, and Claudia began attending Ward Melville High School.

Claudia worked on the SBU newspaper, The Statesman, and its literary magazine, Fortnight. She applied those skills to her work as a book designer, photographer, graphic designer, and cartographer. She worked for The Crown Publishing Group; Farrar, Strauss and Giroux; Oxford University Press and Cambridge University Press. She was a founding member of River Writers of Manhattan, six writers who read their essays, novels, short stories, and poems to each other.

Claudia co-edited “The Poets Grimm: 20th Century Poems from Grimm Fairy tales,” a collection of adult poems on fairy tale themes. She published three volumes of her own poetry — “The Elephant House,” “Pocket Park,” and “My Chocolate Sarcophagus.” She also wrote and illustrated a children’s book, “Avi the Ambulance goes to School,” for her last employer, American Friends of Magen David Adom, the American arm of the Israeli branch of the International Red Cross).

The last three works were written after Claudia’s diagnosis. She told me that she would not die cursing fate or making people uncomfortable. Instead, she would live the fullest for each day she had left. This accounted for the intense productivity in her last two years.

Claudia was treated at Memorial Sloan Kettering Cancer Center until they ran out of experimental drugs to treat her. She elected home hospice as her body weakened. Nedra and I took turns, with our other children, looking after Claudia while her husband was at work. Her sister Christina organized her medical schedule of prescriptions and her visitor’s log. Visitors were limited to one hour so she would not be exhausted.

During these visits, Claudia discussed their work, their reminiscences, and their mutual colleagues. She enjoyed puns and sparkled with wit. She described the return of her hair after radiation for brain metastases as a “reverse Mohawk,” because the most intense radiation ran from her forehead to the nape of her neck. Each two-week trip we took showed how cancer can ravage a body, but Claudia’s courage inspired her colleagues, friends, and relatives, and she showed us how to die with grace and love.

In my mid-84th year, I am not a stranger to the death of those I knew and know. As a biologist, I know it has always been part of the life cycle of all species of plants and animals. The death of all living things is a constant reminder that this is the only life we can guarantee we will have on earth, and it is a gift that can be used wisely, providing a sense of self-worth, making others happy to be around you, and adding to the ever-changing civilization in which we live. I am sure Claudia’s many visitors felt uplifted in their sorrow for the joy she brought to their lives.

Elof Axel Carlson is a distinguished teaching professor emeritus in the Department of Biochemistry and Cell Biology at Stony Brook University.

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By Elof Carlson

Science explores the unknown. I love the history of science because it reveals how science has changed our way of seeing the universe. It rejects the supernatural as an explanation. This has led to the formation of the major fields of science — physics, astronomy, geology, chemistry and biology.

Combinations of these fields are used to explore other fields like oceanography, meteorology or paleontology. Those sciences require data gathering, associations, experimentation and the invention of instruments to obtain data not detectable with our own senses.

Telescopes, microscopes, centrifuges, cyclotrons, cameras, chromatography, space probes, computers, electronic sensors and hundreds of other devices are used in different fields of science to give us information about other planets, stars and galaxies. These tools allow it to smash atoms, sequence DNA or work out how an organism shifts from a fertilized egg to a crying newborn. 

There is another lesson I learned from studying the history of science. We don’t know as much as we think we do. Almost all of modern science from the origin of starlight to the cellular composition of our bodies was unknown before the existence of the right tools and level of understanding of how things worked.

A college science textbook is complete only for the generation of students reading it. It becomes outdated within five years and new texts are required. The new material comes from new tools introduced, new experiments revealing unexpected outcomes and chance findings from sifting through data.

In my own field I would identify as a major unknown the composition and functions of the cytoplasm of the cell. This is the material in which the cell nucleus and membrane-bound organelles are located (the mitochondria, Golgi, endoplasmic reticulum and lysosomes are examples). But the “glop” around them is a gel of sorts and has some cytoskeletal components. What is not known are the component molecules and the structural arrangement of the molecules in the cell cytoplasm that makes it unique to the species. 

You cannot put a fertilized mouse cell nucleus in an enucleated egg of a fish or toad or rabbit. That inability may be a consequence of the products of nuclear genes stored in the cytoplasm that are essential for turning genes on or off after fertilization. Lots of experiments will have to be done to see what’s going on.

That is the challenge of science.  Each new generation of students looks at things in fresh or original ways. The old way of describing and interpreting things gives way.  Sometimes it is rapid, such as the field of molecular biology after the discovery of nucleic acids as the hereditary material. 

Often it is slow.  The discovery of new organs or tissues in the human body is relatively slow.  About once every 20 years or so, I read an article that a new tendon or region of the brain, or some new function of a gland, has been discovered.

No new continents on Earth have been discovered since the polar regions were explored in the late nineteenth and early twentieth centuries. Our technology for photographing Earth makes such a finding virtually impossible. We can predict what we can infer from the known knowledge of our fields, but we cannot predict what is totally unknown to us.

Some seek refuge in such areas of the unknown because they hope to tuck their supernatural beliefs into reality, but it is not reality until that area is fleshed out with data, functions and a comprehension of how things work and can be tested for their predictions and claims.

Elof Axel Carlson is a distinguished teaching professor emeritus in the Department of Biochemistry and Cell Biology at Stony Brook University.

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By Elof Carlson

In 2013, South African cave explorers were told of a chamber with what looked like human bones in the Rising Star Cave system in South Africa. The Sotho language uses “naledi” for its word for a star. When a preliminary examination of some of the bones revealed this was a new species of humans, the formal species name naledi was attached to the genus name to give us Homo naledi. 

Over the next two years, three areas within the chamber were excavated, yielding 1,413 bones or bone fragments, 137 isolated teeth, and 53 jawbones with teeth. They belong to 15 different individuals, all of the same species, H. naledi. 

Their brain size is about that of human ancestors who lived two to four million years ago. Their hands and feet are more human-like than ape-like. Their teeth are remarkably human-like. Their torso, shoulders and pelvis, however, are chimpanzee-like. They were small (four to five feet tall) and, most remarkably, they set aside their dead in a special chamber in the cave. Until this find, no other animal but our own species, Homo sapiens, has been known to provide a special resting place for the dead. 

The digging will continue over the next few years, and many more (perhaps dozens) of fossil members of this species will be uncovered and analyzed. It is rare to have human fossils in such abundance. Where these humans fit in the many branched human, ape and monkey family tree will be worked out as these bones are studied by paleontologists and anthropologists in the years to come.

I look forward to the associated findings that will be explored in the cave and in a careful study of the many bones available.

For those who like the scientific description of a human, we are of the order Primates, the suborder Anthropoides, the superfamily Hominoidea, the family Hominidae, the tribe Hominini, the genus Homo and the species sapiens. Replace that last word with naledi and you see how close we are despite being separated, in all likelihood, by some two to four million years.

It has been satisfying to see the many new fossil humans, apes and related ancestors over the four generations I have lived and to reflect on how the ancestral connections are emerging. It is a story that will continue with more surprises as paleontologists continue exploring the places where humans have resided in the distant past.

Pessimists will see the extinction of humans from natural catastrophes, from human neglect of the world we live in or from alien or supernatural invasion. But four million years have passed and yet another connection to that past is revealed. If the average species runs about two million years, our species, Homo sapiens, has a long way to go before it is just a fossil memory.

Elof Axel Carlson is a distinguished teaching professor emeritus in the Department of Biochemistry and Cell Biology at Stony Brook University.

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By Elof Carlson

Social traits include ethnic or racial identification, religious beliefs, patriotism and class or family status. We recognize that one can be a sports fan and one’s team may be self-chosen the way my father was a Brooklyn Dodger fan, my brother Roland was a New York Giants fan, and I was a Yankee fan. Fan loyalty can be deeply felt, as watching fans at a game often reveals.

We also recognize that children are usually raised in a religion chosen by their parents, which they may later reject or accept. Ethnic identity is more difficult to assess because immigrants frequently keep a lot of the “old country” values and traditions going in their children. But by the time grandchildren or great-grandchildren are born in the United States the melting pot is the norm.

I used to have students in some of my classes prepare genetic pedigrees of their family from grandparents to grandchildren, including uncles and aunts and cousins. What I learned in these exercises was that some Irish married Italians, some Jews married non-Jews, some Catholics married Protestants, some blacks married whites, and it was rare to see three generations in the United States where all members were of one descent (e.g., all Irish or all Methodists).

The farther back one goes in a family’s genealogy, the more these mixtures occur.  This tells me it is not innate to marry one’s own kind. “Birds of a feather may flock together” as a species, but as anyone who has observed dogs will know, any breed of dog can and will breed with other breeds of dogs.

Despite these evidences of cultural mixing and the uncertain religious identification our descendants will have, much of society likes to believe that social traits are inherited. If a family has several generations of physicians, they may believe being a doctor is “bred in the bone” (for those who grew up before World War II) or that it’s in the family DNA (for those who grew up after 1970 when DNA was entering crossword puzzles and rock music — “Hey hey hey hey, it’s DNA that made me that way”).

Most school teachers will experience parents taking credit for their good genes when their children excel in school but the parents may blame the teacher (or the school board) when their children do poorly in their classes. I have never heard a parent say, “It’s my crummy genes that made my child flunk your course.”

The danger of assigning genes to social behavior is that they lead to racist thinking, ethnic stereotyping and beliefs in social class inferiority. The eugenics movement of the first half of the 20th century was filled with these attempts to assign social failure with defective genes (or before the term gene existed to defective protoplasm).

I much prefer evidence based on experimentation or carefully controlled studies. But wishful thinking is easy to do and widely shared, making the world of politics, popular culture and taboo topics seem more real than the science that shatters these illusions.

Elof Axel Carlson is a distinguished teaching professor emeritus in the Department of Biochemistry and Cell Biology at Stony Brook University.