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Elof Carlson

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By Elof Axel Carlson

Elof Axel Carlson

When I gaze at the night sky and look for landmarks like Orion’s Belt or the Big Dipper, I recall my delight as a child reading a picture book on Donald Duck and there he was, on the last page, as a constellation in the sky. 

It taught me that constellations are assigned arbitrary names – is that a big bear (Ursa Major) or is that a big dipper? The stars composing the constellation may differ in age, size, location and chemical composition. It is only their position with respect to our sun that makes them a constellation.

I think of political platforms in the same way. As an old man of 88 years, I remember political campaigns since the 1940s, and in 1940 I saw Roosevelt being driven in an open car in Midtown Manhattan, campaigning for a third term. In those days Republicans took pride in less government interference and, in addition to less taxes and less regulation of business, they favored less interference in our private lives.

They were opposed to bans on family planning and the contraceptives chosen for birth control. In those days the religious right was not sought by either party, and the religious right was still recovering form the pro-fascist sympathies of the KKK, the crushing defeat of Bryan in the Scopes evolution trial in Dayton, Tennessee, on the teaching of evolution in the public schools and the America First movement whose attacks on Roosevelt were slanderous and did not cease until Japan’s attack on Pearl Harbor.

In those post-WWII days, it was the Democrats who were saddled with states’ rights, Jim Crow laws and the religious right. It was in 1948 that the Democrats split into the Dixiecrats and the liberal Democrats.

The Dixiecrats tried forming their own party and failed. It was Nixon and Reagan who accepted the “Southern strategy” to give the Dixiecrats a new home in the Republican Party, and we have continued to see the trend, each party tilting left or right as voting opportunities, demographic change and political opportunism create new constellations of values or platforms for each party.

We live in an inconsistent world with neither extremism nor inconsistency a desired product of our political parties, but nevertheless becoming a reality. While we may be limited in how we shape the political climate, it does help to know that politics lacks the rigor or testing methods of science. We need to keep a healthy skepticism when endorsing the platforms of the party appealing to our political prejudices and ideals.

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

By Elof Axel Carlson

Elof Axel Carlson

Occasionally, I read an item on Facebook that engages my attention. One item asked several celebrities (like successful billionaires) to list the five books they most enjoyed reading and briefly tell why they were important. Here are my five favorite books: 

‘Civilization and Its Discontents’ by  Sigmund Freud

Freud introduces the source of the tensions between creativity and destructiveness. He assigns it to the id/superego conflict. I would use instead our capacity for love, empathy and sympathy versus our capacity for hate, bigotry and violence. Freud calls the process sublimation. He began writing this book in 1929 and published it two years later. He predicted that the rise of Nazism was imminent and would lead to massive death because humanity does not know how to sublimate its discontents into the path of the joys of civilization — its arts, humanity, play and immense scholarship.  

‘Jean Barois’ by  Roger Martin du Gard

This is my favorite novel. It is the story of a young French boy raised by a devout Catholic family who thinks he will become a priest. He discovers instead that the more he learns the more doubts arise not only about his calling but his faith. He teaches biology and is fired for teaching evolution. His wife and daughter separate from him. He throws himself into the Freethinkers movement in France and gets involved in the Dreyfus case. He discovers that reason alone cannot sustain his life but returning to his faith is equally inadequate.  

‘The Essays of Michel de Montaigne’

Montaigne’s essays describe his life and the times in which he lived in the context of a rich appreciation of classical literature. He tries to make sense of a world that is pretentious, at war with itself and filled with irony, contradictions and lessons we can extract from the past. Read a 20th-century translation of these essays rather than the 16th-century English translation. Start with his essay on friendship and his essay: “How by various means we all end at the same place.”   

‘The Diary of Samuel Pepys’

I loved reading Pepys’s diaries and was thrilled that he was an eyewitness to the bubonic plague that swept through England in 1665 and the London fire that destroyed most of the city in 1666. Pepys is an imperfect person — not immune to accepting sacks of gold for awarding contracts for the British Navy, flirting with other women but loving his wife and learning to avoid threats to his career from others drawn to the politics of the time.

‘The Origin of Species’ by Charles Darwin 

Darwin is an excellent observer and narrator. He wrote this book as an abstract of a huge multivolume plan for presenting his theory of evolution of species by natural selection. He is careful to distinguish evidence from theory and uses the facts to derive his interpretations of how evolution works. Darwin did not start with a theory and then seek facts to support it. He went with no idea about evolution and instead allowed the hundreds of observations and findings guide him to the only interpretation that made sense of the relations he found whether it was the work of hobbyists and breeders creating new varieties of plants and animals, the geographic distribution of plants and animals he encountered in his trip around the world, or the fossils he encountered.  


I have learned to sublimate my discontents and have had 14 books published for which I thank Freud. I find Jean Barois to be the finest writing on the conflict between science and belief, science and politics and the difficulty of finding a life that sustains us. Montaigne taught me that in difficult times, we can find many things to avoid and how diverse the world is for each new generation that emerges. I have kept a diary (now 112 volumes) more years than not since I first read Pepys’s diary in 1949. Darwin’s book taught me how to use a Baconian approach to science, letting the data amass and allowing an unbiased mind to connect the dots that make new findings and interpretations possible. 

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

Silkworms are popular among Japanese geneticists because of the silk industry.

By Elof Axel Carlson

Elof Axel Carlson

I got my doctorate working with a model organism, the fruit fly, Drosophila melanogaster. It was introduced to science about 1905 at Harvard where William Castle and his students studied the wing veins of these flies for subtle changes that Darwin’s theory of natural selection proposed. Castle suggested to Thomas Morgan at Columbia that he could use fruit flies for a study of mutations that Morgan hoped to launch. 

Morgan was luckier than Castle because his use of fruit flies led to the discovery of sex-linked inheritance and a process of shifting genes between matched chromosomes. It led to the chromosome theory of heredity and the theory of the gene as a unit of inheritance present in chromosomes.  

Botanists found corn or maize (Zea mays) an ideal organism and classical genetics had inputs from both fruit flies and maize. The most famous contributor to maize genetics was Barbara McClintock who worked out a field of cytogenetics by isolating structural components and consequences for broken chromosomes that experienced rearrangements.  

The bacteriophage viruses and bacteria like Escherichia coli were major contributors to molecular biology. Bacteria are cells but viruses are not. Viruses do have a life cycle, living as destructive parasites or beneficial insertions into bacterial chromosomes. Bacteriophage studies confirmed many of the predictions of DNA as the chemical basis of heredity. They also confirmed that a virus’ proteins are not needed to produce the proteins of its progeny. 

The flow of information goes from the genes as DNA to molecules of RNA carrying the genetic messages to cellular units that translate them into proteins. Bacteria were also used to work out how genes are switched on and off, an important process that regulates how cells work. Most of these early studies in molecular genetics were initiated by Max Delbrück for bacteriophage viruses and by Joshua Lederberg for bacteria. 

For higher organisms a life cycle involves fertilization of an egg by a sperm and the formation of an embryo, which forms different organs with the resulting baby turning into an infant or child and eventually a mature adult and lastly an aged or senescent individual who dies. Sydney Brenner in 1963 suggested using a nematode, the roundworm found in the soil, Caenorhabditis elegans, to work out how this life cycle can be studied at a molecular level. They are similar to the roundworms called vinegar eels seen in flasks of organic apple cider vinegar.  

A fruit fly

Genetics is a composite of the work with many different organisms in plant, animal, and microbial worlds of life. The designation model organism for research biologists distinguishes the usage of research organisms. Applied genetics is often used with specific purposes in mind that benefit the economy. Silkworms are popular among Japanese geneticists because of the silk industry. Tomato geneticists are interested in color, flavor, texture, size and shelf life as they are for most vegetable crops, applying genetics to improve varieties.  

Model organisms were chosen to explore the biology, especially the genetics, reproduction, embryology, metabolism, neurobiology or other fundamental ways living organisms have adapted to their environments and evolved. Biologists working with model organisms often find that once the basic biology is worked out it can be applied to benefit health and the economy. It may take decades before that happens.  

When Calvin Bridges in Morgan’s laboratory found extra or missing chromosomes associated with fruit flies, he did not know that some 40 years later extra chromosomes would be associated with birth defects or disorders in humans such as Down syndrome (trisomy 21) or Klinefelter syndrome (XXY males).  

In some ways humans serve as a model organism. Linus Pauling was interested in how red blood cells carry oxygen from the air and discharge carbon dioxide into it. His curiosity led to a working out of the structure of the hemoglobin molecule and its mutational difference when healthy individuals have their hemoglobin analyzed and compared to that of persons with sickle cell anemia. Pauling called sickle cell anemia a molecular disease. Note that Pauling’s motivation was not that of a physician seeking a cure for a disease but that of a chemist seeking the molecular basis of how we breathe and why oxygen and carbon dioxide ended up exchanging places in red blood cells. 

Humans are also model organisms for the field of neurobiology, especially for processes like memory, learning, association, pattern recognition and speech, most  of which would be difficult to infer from the study of a roundworm’s much limited nervous system. This human study is more likely to be at the physiological and anatomical level rather than the molecular level because there are numerous brain injuries and genetic disorders of the nervous system that can be used to identify where to look for these functions.   

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

Oxford University, Gilman Hall

By Elof Axel Carlson

Elof Axel Carlson

If I had to praise a virtually unknown person as having had the greatest impact on our lives, I would choose Daniel Coit Gilman (1831–1908). Gilman attended Yale University and majored in geography. He became an administrator and founded the Sheffield School of Science at Yale, became the president of the University of California and in 1876 became the first president of Johns Hopkins University. He also helped set up the Carnegie Institution for Science in Washington, D.C.

In 1875 when he was asked to be president of Johns Hopkins University, he embarked on a tour of Europe. He liked the German university emphasis on scholarly research, the ideas of Thomas Huxley on liberal education, and came back with several European scholars who agreed to teach at Johns Hopkins, which opened its program in 1876.

Gilman started his university with a graduate school, then added an undergraduate program and eventually a medical school. He felt the German model was flawed by giving too much power to a single professor in a department who chose subordinates to teach or assist in research. Instead Gilman created departments with several professors committed to scholarship so they could stimulate their research and mentor graduate students who benefited from the multiple outlooks of the department.

By 1910 the success of the Johns Hopkins graduate program shifted the flow of scholars going from the United States to Germany, and after World War I the flow of scholars moved westward to American graduate schools. Gilman’s ideas led to the overwhelming success in Americans winning Nobel Prizes especially in physics, chemistry and the life sciences. It also flooded industries, hospitals and agencies with talented people applying their skills and creativity to their work.

I wish every science teacher would read T. H. Huxley’s “A Liberal Education and Where to Find It” and “On a Piece of Chalk.” They were published about 1868. The first essay shows how Huxley approached education as a way to connect the sciences, art and humanities, shifting knowledge away from an exclusive focus on Greek and Roman civilization as it was then in British schools and toward our connection to the universe in which we live.

Daniel Coit Gilman

The second is an example of good teaching. When I first read his essay when I was about 19 or 20, I could see him in my mind lecturing to the public and holding a piece of chalk in his hand and describing some shavings of it under the microscope revealing the miniature snail-like skeletons of plankton that dribbled down to build the chalk cliffs of Dover. I wanted to be like Huxley, creating lectures that would send shivers of surprise and delight at new knowledge that touched students’ lives.

I singled out Gilman as an educator who changed how knowledge can be learned and transmitted. Our Nobel Prizes and the esteem of rewards are showered on those who make wonderful contributions to knowledge. They are rarely given to founders of institutions that make new ways of learning possible. Both are necessary in our lives.

If I had to single out the one scientist who made the greatest contribution to humanity, I would give that honor to Louis Pasteur for introducing the germ theory of contagious diseases. His use of the microscope to investigate the spoilage of wines turning to vinegar showed that small round yeast cells were replaced by smaller rod-shaped bacteria. His experiments demonstrated numerous infectious diseases as stemming from specific bacteria. It led to vaccinations, public health programs, pasteurization of the milk children drink and the reduction of infant mortality, allowing mean life expectancy to rise from about 45 years at birth to about 80 years today.

New knowledge and inquisitive minds are what make civilization possible.

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

By Elof Axel Carlson

Elof Axel Carlson

There are millions of species of living things. Until the 1860s biologists divided them into two kingdoms, animals and plants.

Louis Pasteur revealed a third group of microscopic bacteria that caused disease, fermented foods (like cheeses), rotted food and decomposed dead organisms. In the mid-20th century this third group, known as prokaryotes, was shown to consist of eubacteria and archaea, differing mostly in how they used energy to carry out their living activities.

Bacteria mostly use oxygen, sunlight and carbon dioxide as fuels and an energy source. Some bacteria are like green plants and use chlorophyll to convert carbon molecules to food and release oxygen. Most of Earth’s atmosphere arose from that early growth of photosynthetic bacteria. Archaea mostly use sulfur, superheated water and more extreme environmental conditions (like deep sea vents) for their energy.

Biologists today identify cellular life as having three domains — archaea, bacteria and eukaryotes. We belong to the eukaryotes whose cells have nuclei with chromosomes. The eukaryotes include multicellular animals, multicellular plants, unicellular protozoa (protists), unicellular algae and fungi.

The two prokaryotic domains and the five eukaryotic groups are designated as kingdoms. A rough time table of early life on Earth would put prokaryotic life about 3.5 to 3.8 billion years ago, the first free oxygen in our atmosphere about 3.5 billion years ago, the first eukaryotic cells about 2.5 billion years ago and the first multicellular organisms about 1.5 billion years ago.

The branches of the tree of life biologists construct have an earliest ancestor called LUCA (for the last universal common ancestor of a particular branch). There may have been a biochemical evolution preceding the formation of the first cellular LUCA with RNA and protein associations, RNA and DNA associations and virus-like sequences of nucleic acids.

The three domains have produced six million different genes. Molecular biologists have identified 355 genes that all cellular organisms share in common. This is possibly the genome of the LUCA of all living cellular organisms. Whether such a synthetic DNA chromosome could be inserted into a bacterial or archaeal cell or even a eukaryotic cell whose own DNA has been removed has not yet been attempted. It may not work because we know little about the non-DNA components of bacterial or archaeal cells.

Biologists have known for some time that a nucleus of a distant species (e.g., a frog) placed in a mouse egg whose nucleus has been removed will not divide or produce a living organism. But two closely related species (like algae of the genus Acetabularia) can develop after swapping nuclei. In such cases the growing organism with the donated nucleus resembles the features of the nuclear donor.

There is a LUCA for the first primate branch with the genus Homo. We are described as Homo sapiens. Anthropologists and paleontologists studying fossil human remains have worked out the twigs of the branch we identify as the genus Homo. Neanderthals and Denisovans (about 500,000 years ago) are the two most recent branches that preceded the origins of H. sapiens (about 160,000 years ago). Most humans have a small percentage of Neanderthal or Denisovan genes. Fossils of Homo erectus (about 1.8 million years ago) or Homo habilis (about 2.8 million years ago) are much older than the recent three species of Homo. Those fossils do not have DNA that can be extracted from teeth.

A second objective of studying LUCA’s 355 genes will be the identification of each gene’s function. That will tell biologists what it is that makes these genes essential in all cellular organisms.

I can think of a third important consequence of studying LUCA. There are millions of different viruses on Earth, especially in the oceans. If cellularity arose from clusters of viruses, the genes of the mother of all LUCAs may be scattered among some of those viruses and give biologists insights into the step-by-step formation of that first LUCA cell.

In Gilbert and Sullivan’s operetta, “The Mikado,” one character boasts of tracing his ancestors to a primordial bit of protoplasm. The genome of LUCA might become an unexpected example where science imitates art.

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

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.