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Elof Carlson

By Elof Carlson

William Bateson (1861-1926) grew up in an academic home and attended Cambridge University where he took an interest in embryology. He went to Johns Hopkins University to learn the new experimental approaches and insights into the cellular events leading to embryo formation. While there, he was inspired by William Keith Brooks who urged him to study heredity if he wanted to contribute to a field in need of scientific rigor.

When he returned to England, Bateson studied variations and identified two types that were unusual. He called one group homeotic changes because they put organs in the wrong place, such as a fly’s leg emerging from an eye. The other group he called meristic variations, which duplicated parts, like a child born with six fingers on each hand and foot. Both meristic and homeotic mutations were considered pathological by most breeders and physicians, but Bateson believed they could be the raw material for new organ systems or more dramatic origins of new species. He published the results of this work in 1894, and it made him regarded as an enemy by British Darwinists who favored all mutational change as gradual and never sudden.

In 1900 Bateson read Mendel’s papers and was immediately won over to his approach. He began studying mutations in plants and animals. He also gave a name (in 1906) to this new field and called it genetics. Bateson used the symbols P1, F1 and F2 for the generations of a cross. He used the terms homozygous and heterozygous for the genotype of the individuals in a cross. He described the mutant and normal states of hereditary units as alleles.

Bateson discovered blending types of inheritance and genetic interaction in which two or more nonallelic genes could jointly affect a trait. He even found (but did not correctly interpret) non-Mendelian recombination of genes. In this he was scooped by Thomas Hunt Morgan and his students. Morgan was also a student of Brooks at Johns Hopkins and, like Bateson, originally skeptical of Darwinian subtle variations as the basis for all of evolution. But Morgan added cytology to his studies and related the hereditary units (called genes after 1909) to the chromosomes on which they resided.

Bateson felt chromosomes had little to do with genetic phenomena. He was wrong and it was not until the 1920s that he grudgingly admitted Morgan’s fly lab had advanced the field of genetics he named.

Bateson’s work led to an explosion of interest in the field of genetics, and, while he was trapped by his views of the time, younger scientists had no difficulty adding genes to chromosomes, mapping them and accounting for the transmission of traits through their behavior during cell division and germ cell production.

In 1910 Bateson was probably the most famous geneticist in the world. By 1920 he was fading, and after his death in 1926, he was largely forgotten to all but historians of science.

That is not uncommon in the history of science. Science changes faster than any individual scientist can change views in a lifetime. Despite the loss of prestige, it is fitting to honor the memory of the person who named the field of genetics and whose battles to make Mendelism its core succeeded over the prevailing views of heredity at the end of the nineteenth century.

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

Fossils are relatively rare because most of the animals and plants that have died in nature have been eaten or decomposed. Fossils are often found in sedimentary rocks, and those dead organisms were buried after drowning, caught by volcanic ash, buried in a mudslide or sucked down by quicksand or some other event less likely than falling on a field or in the underbrush of a forest, or left as scattered bones by hungry predators. Only in the past few ten thousand years have humans buried their dead, improving the chances that their remains will someday be unearthed and studied by paleontologists.

DNAUntil the last half of the twentieth century, the only way to use human fossils to work out a historical association was through comparative anatomy and a variety of chemical and physical tools to determine the age of the sediments in which they were unearthed. The idea of a paleogenetics arose in 1963, with the use of that term by Linus Pauling and his colleagues, who studied the amino acid sequences in hemoglobin molecules of numerous organisms, from sipunculoid worms to humans, that use hemoglobin to carry oxygen to body tissues.

In 1964, the first sequence of fragments of the DNA of an extinct quagga were worked out using the skin of an extinct specimen in a museum. The quagga was an animal that looked like a chimera of giraffe and a zebra.

Once DNA sequencing was worked out, especially by Fred Sanger and his colleagues, viruses, bacteria, single-celled organisms, and then more complex worms and flies were sequenced. By 2000, the human genome was being worked out. Svante Pääbo and his colleagues are leaders in the working out of fossil human DNA.

This is what has been found so far. Four contenders for species status lived about 40,000 years ago. Three populations of humans arose after an initial origin in Africa. Of these three, the Neandertals (Homo neanderthalis) left Africa earlier than our own Homo sapiens. The Neandertals were named for the Neander river valley where they found in Germany. We were named by Linnaeus as Man (Homo) the Thinker (sapiens).

Two additional populations were found, one in western Siberia and the other in Indonesia. The Siberian humans are called Denisovans (Homo denisova). They were named for the Denis cave in which they were found and they also had an exit from Africa. The Indonesian humans are called Homo floresiensis and are named for the island Flores in Indonesia where they were found. Where they came from is not yet known. They are unusual for their small size, a Hobbit-like three- and-a-half feet tall.

The DNAs of three forms of humanity have been sequenced. The complete sequence of DNA of an organism’s cell is called a genome. The Indonesian form went extinct about 12,000 years ago, but no DNA has been extracted from their remains. Neandertals and Denisovans went extinct about 40,000 years ago.

Analysis of the three available genomes shows that most Europeans have about 4 percent Neandertal DNA. Living people in Melanesia and Australian aborigines have about 4 percent H. denisova DNA. About 17 percent of Denisovan DNA is from Neandertals. The human branch Homo bifurcated and one branch split into H. neanderthalis and H. denisova. The other branch from Homo produced us, H. sapiens. We are 99.7 percent alike for H. sapiens and H. neanderthalis.

Since we have 3 billion nucleotides to our genome, there remain 9 million mutations between us, most of it in our junk DNA. There are, nevertheless, hundreds of gene differences between our two species. It also means that where these populations came into contact, fertile matings occurred, and remain in our DNA from our ancestral “kissing cousins.”

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

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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By Elof Carlson

For the past four years I have participated with a writing group at Indiana University’s Emeriti House, where old-timers like me gather and once a month discuss what we have written. I much enjoy listening to the stories told.

A Norwegian opera singer described his youth near Oslo on an island in a fjord and how that idyllic childhood was shattered by the Nazi occupation. A linguistics professor discussed what it is like to eat with one’s hands in Kathmandu where table manners are very different than the world of knives and forks or chopsticks. A Spanish teacher described her adventure learning how to chop wood with a wedge. A journalism professor described sailing a boat alone from New England to Florida and back. Along the way we learned that some growing up experiences were frightening, especially those who were refugees during WWII in the Baltic states.

A different opportunity arose recently when my daughter Christina located the granddaughter of my Uncle Charles Vogel. I had seen him a few times as a child when my mother would visit him at his home in Brooklyn. He sold clothing door to door and he gave me about a dozen ties so I could wear them to my high school. My mother said he sold to gangsters. I never knew if this was part of my mother’s psychotic beliefs or real, but I downloaded this previously unknown relative’s manuscript called “Charlie’s story” based on a 1985 interview she had with her grandfather. It turned out he sold men’s clothes to Al Capone, Gaetano Luchese, Lucky Luciano and Albert Anastasia. He also survived a disastrous childhood accident in Bound Brook, New Jersey, when he was hit by a car that had him hospitalized for a year. Later he ran away to join the Barnum & Bailey Circus until his father located him. These family stories are usually oral and then forgotten after a couple of generations. But if someone types them up after an interview, they can be part of the delight of tracing our ancestors and seeing how things change over several generations.

Social history decays rapidly, and many of us have only scattered memories of our childhood. We know virtually nothing about our grandparents’ or great grandparents’ lives. If we have our DNA examined for selected genetic markers, we can identify different ethnic components (Asian or African or Middle Eastern or Native American). Each person who has a European ancestor is related to virtually every person in Europe if one goes back 2,000 years (something difficult to do for those who do not have a royal lineage).

All Native Americans in the western hemisphere are related to ancestors who lived in eastern Siberia about 15,000 years ago. The genetic crumbs of information of this past ancestry tell us little about who these people were and what they did. But what we preserve as memoirs can last for many generations delighting our descendants. Every time I open up a volume of Samuel Pepys’ diary the world of the 1660s shifts from history to eyewitness narrative.

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