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Elof Carlson

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'A trip to the American Museum of Natural History was my idea of being in heaven.' - Elof Carlson

By Elof Axel Carlson

The life sciences are vast in the number of specialties that exist for those pursuing a career as a biologist. A majority of college biology majors are premedical or seek some sort of health-related field. As much as possible they hope the biology they learn will find its way into the health field they seek to enter. Persons who want to be scholars in biology are often motivated by a desire to know as much about life as they can. I was one of those from early childhood when a trip to the American Museum of Natural History was my idea of being in heaven.

Elof Axel Carlson

I loved learning about evolution and the diversity of life. I knew I wanted to be a geneticist when I was in ninth grade and learned about Paul Müller’s Nobel Prize work on inducing mutations. Like a duckling, I felt imprinted and wanted to work with Müller someday.

Graduate work was different. As a teaching assistant I got to see about 90 different specimens each week for the various organ systems displayed by students. Unlike the textbook perfect illustrations, veins and arteries could be slightly off in the specimens I looked at. Their colors differed. Their texture differed.

I also learned how much we didn’t know about life. For my specialty of genetics (with Müller, as I had hoped) I felt steeped in experimental design, techniques and ways of thinking. Doing a Ph.D. allowed me to examine a gene using the tools of X-raying to produce mutations of a particular gene and subtle genetic design to combine pieces of a gene — taking it apart and combining pieces that were slightly different. It gave me an insight into that gene (dumpy, in fruit flies) that for a short time (until I published my work) I was the only person in the world that knew its structure.

In my career I have taught biology for majors, biology for nonscience majors, genetics, human genetics and the history of genetics. I have taught lower division and upper division courses, graduate courses and first-year medical classes. I learned that sharing new knowledge with students excited their imaginations. I learned that the human disorders I discussed led to office visits; and if I didn’t know the information they sought, I went with them to the medical library and we looked up articles in the Index Medicus and discussed their significance.

Often that student was married and had a child with a birth defect (born without a thyroid, having a family trait that might appear like cystic fibrosis). I would prepare a genetic pedigree and give it to the student to stick in a family bible for future generations to read. I also delighted in going to meetings to discuss genetics with colleagues whose work I had read.

I was pleased that I shared a body plan with other mammals. I liked comparative anatomy, which taught me how other body plans work (mollusks, arthropods, worms, coelenterates, echinoderms). As a graduate student taking a vertebrate biology course, I went into a cave and plucked hibernating bats from a ceiling.

The world under a microscope is very different. To see amoebas, ciliated protozoans, rotifers and other organisms invisible to the naked eye or as mere dust-like specks is a thrill. I can go back in time and imagine myself as a toddler, a newborn, an embryo in my mother’s uterus or an implanting blastocyst rolling out of her fallopian tube. I can imagine myself as a zygote, beginning my journey as a one-celled potential organism typing this article into a computer. I can go back in time to my prehistoric ancestors and trace my evolution back to the first cellular organism (bacteria-like) more than 3 billion years ago.

I learned, too, that I contain multitudes of ancestors who gave me one or more of their genes for the 20,000 I got from my father’s sperm and the matching 20,000 genes in my mother’s egg nucleus. I contain some 37 trillion (that is, 37,000,000,000,000) cells or 2 to the 45th power, which means some 45 mitotic cell divisions since I was a zygote. I know that the warmth of my body is largely a product of the mitochondrial organelles in my cells that using the oxygen from the air I breathe and converting small molecules of digested food to provide energy that runs the metabolism of my body and disposes carbon dioxide that eventually is expelled from my lungs. This knowledge makes me aware of my vulnerability at the cellular level, the chromosome level and the genetic level of my DNA to the agents around me that can lead to birth defects cancers, and a premature aging.

Knowing my biology allows me to know my risks as well as new ways to celebrate my life.

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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Charles Darwin

By Elof Axel Carlson

Elof Axel Carlson

An intellectual pedigree traces the power of mentoring across many generations. I got my Ph.D. in genetics with Nobel laureate Hermann J. Muller at Indiana University. Muller got his Ph.D. in genetics with Thomas H. Morgan also a Nobel laureate at Columbia University. Morgan got his Ph.D. in embryology with William K. Brooks at Johns Hopkins University.

Brooks got his Ph.D. in comparative anatomy with Louis Agassiz at Harvard. Agassiz came from Europe. He got his Ph.D. in ichthyology (fossil and live fishes) with Georges Cuvier in Paris. Cuvier got his doctorate in comparative anatomy from Ignaz Döllinger in Germany. Döllinger got his Ph.D. at Padua in Italy studying embryonic development. He was mentored by Antonio Scarpa at Modena in Italy.

Scarpa was mentored by Giovanni Morgagni at Padua. Morgagni was mentored by Antonio Valsalva who named the Eustachian tube, and he was mentored by Marcello Malpighi an early microscopic anatomist. Malpighi was mentored by Giovanni Borelli who first used physics to describe animal motion relating bones and muscles to function. Borelli was mentored, in turn, by Benedetto Castelli a mathematician and astronomer who studied sun spots. Castelli was mentored by Galileo Galilei.

I followed the history two more generations. Galileo was mentored by Ostillio Ricci. Ricci was mentored by Niccolò Fontana Tartaglia, another mathematician whose text on applied mathematics was a best seller in Renaissance Italy. From my Ph.D. in 1958 to Tartaglia’s years of birth and death (1499-1557) is a span of about 450 years.

If I number Tartaglia as 1, I am generation 16. Not all had a Ph.D. as their highest degree. Some had the M.D. The modern university as a research and teaching institution dates to the late 1700s in Germany. The Medieval and Renaissance university was based on the seven liberal arts leading to the B.A degree. Students could then choose law, medicine, theology,. or philosophy as a specialty leading to a M.A., M.D. or Ph.D. Nicolaus Copernicus got degrees in canon law (laws applied to and by the church), medicine and philosophy.

The M.D. degree until the late 1890s used to require a book-length dissertation as did the Ph.D. Note that German science was influenced by the Italian universities that took an interest in observational and experimental science in the Renaissance. It was Döllinger who brought this tradition back from Padua.

There was no scientific tradition at the university or college level in the United States until the 1870s when Cornell, Yale and Johns Hopkins stressed the Ph.D. as a scholar’s degree. Prior to that most American colleges stressed training for the ministry. Agassiz brought that scholarly tradition to Harvard to bolster American science.

I have done intellectual pedigrees for William Castle, Ralph Cleland, Seymour Benzer, Theodosius Dobzhansky, J.B.S. Haldane, Barbara McClintock and a few other geneticists. They usually differ. That means not all roads lead to Galileo. A few plug in to Agassiz or Döllinger. I was pleased to trace McClintock back to Carl Linnaeus. They are fun to do and you can use Wikipedia for the biography of a scholar you wish to follow. It will give (most of the time) the person who supervised a thesis or the names of that person’s best known students.

I also learned that sometimes there is more than one major mentor in a scholar’s life. Morgan was mentored by Brooks, but he was also mentored by H. Newell Martin who was a student of Michael Foster who was a student of Thomas H. Huxley, who was mentored by Charles Darwin. That means, I too, have a branch that leads to Darwin.

I learned from these pedigrees that we are shaped by what we experience. We are shaped by our parents and their community. We are shaped by mentors in high school or college. Sometimes it is through a course we take. Sometimes it is in our volunteer or extracurricular activities. Also, we have influence on more students than those who come for a Ph.D. research experience. In my career, this can be through the courses I taught, the office visits I had or the chance encounters with students while eating lunch, serving on committees that brought me in contact with them or serving as an academic advisor for my department.

Life gives us opportunities to be thankful. I thank the 15 generations that preceded me in my life as a scientist and teacher. What each generation gave was an opportunity to discover and to learn, to relate and to communicate, to lecture and to write.

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

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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Egypt has long been considered a land of mystery and magic. Above, the Magical Circle of Anubis is discussed in ‘The Golden Bough.’

By Elof Axel Carlson

In 1890 Sir James George Frazer (1854-1941) wrote “The Golden Bough.” Frazer was Scottish, educated in Glasgow and then in Cambridge studying classical literature (Greek and Roman). He studied mythology, comparative religion and anthropology. His book argues that magic gave rise to religion and religion to science.

Magic assumes there are supernatural powers that some people can invoke or possess as innate gifts. With magic, what seems impossible can be made possible, at least to the observers of magical acts. Most professional magicians deny that they possess such gifts, and Houdini spent considerable time duplicating the tricks and illusions other magicians (and charlatans) used to deceive the public.

Frazer surmises the earliest humans believed in magical acts and associated them into rituals and myths with a belief in gods, often family ancestors, mythic heroes who were founders of a tribe, clan or larger population and sky gods. He believed the idea of resurrection came from the seasonal observation that plants die, scatter seeds and in the spring a resurrection occurs. He calls this “the dying corn god.”

Religion largely replaced magic as the basis for interpreting how the world arose, how society should function and how we relate to our gods. Religion in turn led to science with mathematics replacing numerology, astronomy coming out from astrology and chemistry from alchemy. The pursuit of knowledge from pseudoscience led to a weeding out of the failed experiments and predictions and a respect for more empirical and reason-based studies of the material, living and psychological universe in which we live.

Contemporary historians and philosophers differ with Frazer and among themselves on the origins of science. Some use a Marxist interpretation that farmers and workers laid the groundwork for science by their practical approaches to cultivate nature. Some argue that science is actually a cultural consensus or construction that shifts to new consensus and constructions in response to political and cultural changes.

Most scientists reject these social views of science and favor a material universe that can be explored, interpreted and manipulated with tools, experimentation, reason and data replacing myth, ideology or the supernatural. At issue in these debates are the ways scientists see the universe and their efforts to understand it. Science sometimes overthrows prevailing beliefs seen as truths. More often, it modifies its findings and its implications, incorporating the old as a portion of the new.

Newton’s laws of motion and gravity were not negated by Einstein’s theories of relativity or space-time. They became a more limited application useful for studying Earth and its solar system. Science is limited in what it can predict. We do not know if there are few, many or an unending number of scientific laws that may emerge in the centuries and millennia to come.

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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Most snakes ... have no sign of limb development when X-rayed or when their skeletons are studied by anatomists.

By Elof Axel Carlson

Elof Carlson
Elof Carlson

The re-discovery of Mendelism in 1900 greatly enhanced breeding for new varieties of animals and plants. Similarly, the discovery of sex chromosomes and the chromosome theory of heredity enhanced Mendelism five years later. The discovery in the 1970s of genes controlling embryonic organs and body plans enhanced both embryology and genetics.

Also in the late 20th century a molecular approach was worked out that allows detection of genes and their functions using DNA sequencing and tools for isolating and inserting genes from one species into another. A good example of this is the analysis of limb development in vertebrates.

We are vertebrates because we have a spinal column and so do fish, frogs and tetrapods (four-limbed organisms like mice, humans, deer and lizards).

But some vertebrates lack limbs. Snakes are the best example of this. Boas and pythons do have internal vestigial hind limbs but totally lack any rudiments of limbs for their forelimbs. Most snakes, like vipers, have no sign of limb development when X-rayed or when their skeletons are studied by anatomists.

How did the snakes lose their limbs? The earliest ancestors of snakes did have hind limbs. Those ancestral types are only known from the fossil record. In the 1970s Hox genes, which determine development from the head to the tail, were found in vertebrates. The Hox gene for limb development is Hox C-6. It is regulated by another gene called sonic hedgehog or Shh. In vipers the Shh gene regulating Hox C-6 is mutated for both fore and hind limb production. In pythons it is nonfunctional for forelimbs but mutated with an aborted development preventing full growth of the hind limb buds.

Just this year, molecular biologists used the new techniques of gene removal and transfer (using a tool called CRSPR) and removed the Shh gene from a mouse fertilized egg. It resulted in a limbless baby mouse. When they put a python’s Shh gene in a mouse embryo whose Shh gene was removed, the resulting baby mouse had vestigial nubbins. When a mouse fertilized egg had its own Shh gene removed and replaced by that of a fish or human Shh gene, the baby mouse had perfectly normal limb development.

This work by Axel Visel and colleagues at Lawrence Biology Laboratories in Berkeley was published in the journal Cell. What makes science so attractive to scholars is its convincing logic, tested by experiments, to explore, confirm or rule out different interpretations of a puzzle. The puzzle of nature in this case is why snakes lost their limbs.

Those who see it in human terms (because we often use the ancient Greek dictum “Man is the measure of all things”) may invoke that the snake was punished for its role in corrupting humans. The scientist, however, likes to see things in more detail. There is comparative anatomy, the fossil record, experimental embryology, gene identification for function, sequencing for recognizing the gene, molecular tools for isolating the gene and experimental means of altering fertilized eggs to follow their fate.

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

Elof Carlson
Elof Carlson

In politics we use the term politically correct to describe what we believe is an insincere phrase to hide a harsh reality. Thus to those who object to elective abortions as an act of murder, the term pro-life is favored. To those who feel this is a woman’s decision, the term pro-choice is favored.

What about describing the learning abilities of a child? When intelligence tests used to be applied to all children in public school starting in 1910, terms like feebleminded were replaced by terms like imbecile, idiot and moron on the low end of intelligence quotient measurements and terms like gifted and genius for the high end.

By the 1950s these low-end terms were replaced by the term retarded, but the high-end terms (flattering to parents) were retained. By the 1980s the term retarded was dropped in favor of exceptional child where the term exceptional could be used for any departure from average but usually was applied to what formerly were called retarded children.

There is less argument, however, about physical descriptions of children with disabilities or departures from average appearance or function. I doubt if those who dislike political correctness would want to replace today’s Down syndrome (or trisomy 21) with its original term mongoloid idiocy. Would you rather have your child described as having Tay-Sachs syndrome or its prior description as infantile amaurotic idiocy? Would you rather have your child described as having Hurler syndrome or its original term gargoylism?

In the 1970s terms with racist (mongoloid idiot) or insulting (happy puppet syndrome) connotations were replaced with neutral names, usually the name of a physician who first described the condition or the family in which it originally occurred. The term senile means old (and its root is found in innocuous terms like senior or senator), but in common use for senile we think of the negative side of aging — loss of mental acuity, deteriorating hearing or vision, loss of capacity to smell, arthritic achy joints, impotence, incontinence and a host of degenerative conditions.

I am old but still (fortunately) capable of writing books and articles. While being old is not a blessing, I do enjoy having an income (pension and Social Security) without having to worry each day about going to work. I have time to read lots of books. Nedra and I can enjoy traveling whenever we wish to do so. But I would not say to others that these are my senile activities.

Politicians call these slogans acts of spinning. My English teachers called them euphemisms. Psychologists call the practice reframing. Diplomats call the practice tact. Caring or thoughtful people call it sensitivity. In the vernacular it is about not calling a spade a spade.

Some find it refreshing to use the older terms and phrases because it may disguise or subtly reveal the underlying bias the terms harbor. But sometimes reframing leads to delightful wit like Alban Barkley at the Democratic convention in 1948 who responded to claims that Democrats were bureaucrats. “What is a bureaucrat?” he asked. “A bureaucrat is a Democrat who has a job a Republican wants.”

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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Stock photo

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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Dolly the sheep. File photo

By Elof Axel Carlson

Dolly was a Dorset Finn breed of sheep born in 1996 in Scotland. She was conceived from a nucleus taken from a breast cell of an adult healthy sheep that was transferred into the cytoplasm of an egg of a different breed whose nucleus had been removed.

Dolly was the first successful live-born lamb out of about 250 tries. She was named for Dolly Parton. Ian Wilmut and Keith Campbell were the scientists who constructed her. Dolly began developing arthritis at age 5 and died a year later showing signs of old age. Normal life expectancy for a Dorset sheep is 12 years. It was thought that the cloning nucleus from the donor Dorset sheep passed on its age to Dolly at birth and that this led to her premature aging. That turned out to be false.

Kevin Sinclair, a developmental biologist in England, obtained four live clones from the breast tissue that was used to make Dolly. The successful live-born sheep were named Debbie, Diana, Daisy and Denise. They are now (2016) 9 years old and in perfect health.

Cloning is still inefficient and more failures (mostly during early embryonic stages) occur than successes. Success with dogs in Japan has led some pet owners to pay for a cloned twin of a favored aging pet. In Dolly’s case an electric shock was used after the transfer of the nucleus to stimulate the cell to divide. For some embryologists a series of transfers to fresh enucleated eggs is required to achieve success.

Why most fail is not known, but the field of epigenetics may supply some of the answers. Genes are coated chemically by the organism in body tissues. Normally, in males and females these coatings, which regulate whether genes are on or off, are removed in the testes or ovaries where reproductive cells are made. I do not doubt that in a decade or so scientists will learn to do that in a test tube or Petri dish. Will that technology be used commercially? Very likely. Prize race horses and beef or milk cattle could be cloned if the success rate was about 70 percent. It will probably not be better than that because natural fertilization fails in about one third of fertilized eggs, a substantial part of that being extra or missing chromosomes when sperm or egg nuclei are produced.

Living things are very complex and the chance of getting almost 100 percent “perfect” cells is virtually impossible to achieve. That is why many couples attempting to have children often take months or years before they become pregnant or seek help from an in vitro fertilization clinic.

The success of Dolly’s cloned sibling sheep worries some medical ethicists that, if applied to humans, this could be abused by narcissistic personalities who want to clone themselves. So far that hasn’t happened and many countries (and states in the U.S.) have banned cloning using human tissues. For those who enjoy watching (and betting on) horses, it raises an interesting idea. If races were eventually done with cloned champions, it would favor the training over the breeding as the basis for who wins. Imagine a field of a dozen cloned Seabiscuits and trying to figure out whose training was the best.

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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Most market tomatoes are recent varieties created in university and commercial farms since 1940. Stock photo

By Elof Axel Carlson

The tomato is botanically a fruit or more specifically a berry. We think of it as a vegetable because of its use in pasta sauces, soups and stews. The Supreme Court in 1893 ruled that for taxing and tariff purposes, it is a vegetable because of its usage in cooking.

The tomato belongs to the species Solanum lycopersicum. Thus, it belongs to a family of some 3,000 species worldwide. But tomatoes arose and were cultivated in the Andes and made their way to Mexico where they were domesticated. From there they were imported to Europe in the 15th century.

Because they are classified as members of the Solonaceae family, which includes the deadly nightshade, they were sometimes regarded as poisonous. But the domesticated tomato varieties began appearing in Spain, Italy and England and soon spread as far as China, which is now the world’s largest consumer and producer of tomatoes.

The tomato gets its name from the Aztec word “tomatl.” Until 1940 the domesticated tomatoes throughout the world came from the Mexican varieties the Spanish brought back in the late 1400s and early 1500s.

The tomato plant cell has a total of 24 chromosomes, and its pollen or ovules have a chromosome number of 12. Their genome was not worked out until 2009, and a comparative study of 360 varieties and species of tomatoes was published in 2014. The pre-1940 tomato varieties for food had very few of the mutant gene varieties found in the wild species in South America (less than 10 percent).

Thus, most market tomatoes are recent varieties created in university and commercial farms since 1940.

The farmers buy hybrid seed, and tomato seed companies make sure that their seeds are hybrid to keep farmers from planting crops from the tomatoes that are harvested. This was a policy first started by agribusiness for hybrid corn beginning in 1908.

The genomic analysis of tomatoes and their related species give an evolutionary history of tobacco, then peppers, then eggplants, then potatoes and finally tomatoes as the sequence of species emergence. The molecular insights into plant genomes, by sequencing their genes, have led to a controversial field of genetically modified foods.

One of the first was short lived. I remember buying “Flavr Savr” tomatoes in a supermarket in Setauket. The manufacturer had inserted a gene for delayed ripening and thus longer shelf life in stores. I could not tell any difference in taste or texture from those manufactured by inserting genes from other varieties of tomato plants.

Just as people in the 1500s feared tomatoes when first introduced into Europe as likely to be poisonous (they weren’t), the fear of genetically modified foods led to their quick demise in the market. Today it is almost impossible to buy foods (grains, vegetables, fruits, fish, fowl, or livestock) that are guaranteed to be free of genetic modification.

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

I recently had the pleasure of reading Lee Standlin’s “Storm Kings,” a short work on the history of weather forecasting and how scientists tried to figure out how storms form. The book begins with Benjamin Franklin’s discovery that lightning is electricity. I learned that Franklin was quite a showman as he toured Europe and the Colonies, showing his experiments with electricity.

I knew that much earlier people tried to interpret weather as the acts of gods. For the Norse, Thor was the god of thunder. For the Greeks, Aeolus was the deity who blew gale winds and caused ships to crash and sink under gigantic waves. For the Bible, Genesis describes the “waters above” and the “waters below,” distinguishing oceans from drenching rains as two separate creations of water.

In “Storm Kings,” we follow the bitter controversies of nineteenth century scientists who attempt to explain storm formation. Each participant is hostile to the ideas of rivals and theories collide with the ferocity of storms. But out of those debates, the Army Signal Corps was formed and established first, a series of flags to indicate weather for ships at sea and then, telegraph accounts of weather readings — temperature, barometric pressure, clouds, wind speed and direction — sent to military bases around the United States.

Politics played a role in the rivalry of contending candidates for heading up the Signal Corps and politics limited what it could forecast. Tornadoes were taboo because acknowledging them or determining their frequency would lower land values in the Midwest. The Signal Corps was cut back, had its operations shifted to the Agriculture Department and was renamed the Weather Bureau so it could be more effectively monitored by lobbyists.

After the Civil War, science began to change. Weather was seen as a complex physical process and weather fronts were identified. The collision of warm moist air from the south and cold dry air from the north led to line storms and tornadoes in the Midwest. It was not until World War II that a more thorough weather forecasting was allowed for the Weather Bureau.

What distinguishes the history of weather forecasting as a science from evolution in biology as a science is the relative absence of religious objections to the interpretation of storms and weather phenomena.

Disasters are still thought by some as visitations from God to punish the wicked. But no one would ban the teaching of the physics of storm formation or cloud formation in classrooms.

Astronomy and physics are also downgraded by some religious writers who deny the idea that objects can be more than 10 thousand light years away or that some elements in the earth have a radioactive decay rate measured in millions of years.

The brunt of the attack on science, however, is evolutionary biology, because it deals with life, and we humans are alive and aware of that existence. Most people have no clue what is meant by light years, radioactive half-lives of isotopes of elements, or the dynamics of ocean currents, wind patterns, and rising or descending masses of air. Unfortunately, almost all major religions have their origins hundreds or thousands of years ago when science was relatively new or altogether absent and the religious texts of those times reflect this.

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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