Америкалық генетик Сеймур Бензердің өмірі мен ғылыми еңбектері

American geneticist

Seymour Benzer (October 15, 1921 – November 30, 2007) was an American physicist, molecular biologist and behavioral geneticist. His career began during the molecular biology revolution of the 1950s, and he eventually rose to prominence in the fields of molecular and behavioral genetics. He led a productive genetics research lab both at Purdue University and as the James G. Boswell Professor of Neuroscience, emeritus, at the California Institute of Technology.

Benzer was born in the South Bronx to Meir Benzer and Eva Naidorf, both Jews from Poland. He had two older sisters, and his parents favored him as the only boy. The book Arrowsmith by Sinclair Lewis heavily influenced the young Benzer, and he even imitated the handwriting of Max Gottlieb, a scientist character in the novel. Benzer graduated from New Utrecht High School at 15 years old.

At Brooklyn College, as a sixteen year old freshman, Benzer met Dorothy Vlosky (nicknamed Dotty), a twenty one year old nurse. He later married her in New York City in 1942. spending two years as a postdoctoral fellow in Max Delbrück's laboratory at California Institute of Technology, and then returning to Purdue. At Purdue University, Benzer developed the T4 rII system, a new genetic technique involving recombination in T4 bacteriophage rII mutants. After observing that a particular rII mutant, a mutation that caused the bacteriophage to eliminate bacteria more rapidly than usual, was not exhibiting the expected phenotype, it occurred to Benzer that this strain might have come from a cross between two different rII mutants (each having part of the rII gene intact) wherein a recombination event resulted in a normal rII sequence. Benzer realized that by generating many r mutants and recording the recombination frequency between different r strains, one could create a detailed map of the gene, much as Alfred Sturtevant had done for chromosomes. Benzer's work influenced many other scientists of his time (see Phage group). In his molecular biology period, Benzer dissected the fine structure of a single gene, laying down the ground work for decades of mutation analysis and genetic engineering, and setting up a paradigm using the rII phage that would later be used by Francis Crick and Sydney Brenner to establish the triplet code of DNA. In addition, Benzer's mapping technique was taken up by Richard Feynman. Benzer and Hirsch's competing philosophies served to provide necessary scientific tension in order to accelerate and enhance developments in behavioral genetics, helping it gain traction as a legitimate area of study in the scientific community.

Benzer used forward genetics to investigate the genetic basis of various behaviors such as phototaxis, circadian rhythms, and learning by inducing mutations in a Drosophila population and then screening individuals for altered phenotypes of interest. Benzer identified mutants for a wide variety of characteristics: vision (nonphototactic, negative phototactic, and eyes absent), locomotion (sluggish, uncoordinated), stress sensitivity (freaked out), sexual function (savoir faire, fruitless), nerve and muscle function (photoreceptor degeneration, drop dead), and learning and memory (rutabaga, dunce). Benzer and student Ron Konopka discovered the first circadian rhythm mutants. Three distinct mutant types—arrhythmic, shortened period, and lengthened period—were identified. These mutations all involved the same functional gene on the X chromosome and influenced the eclosion rhythm of the population as well as rhythms in individual flies' locomotor activity. To monitor Drosophila locomotor activity, Benzer and postdoctoral researcher, Yoshiki Hotta, designed a system using infrared light and solar cells. The work with Period mutants was catalytic in the study of circadian rhythms and served to propel the field forward. On 2 October 2017, Dr. Rosbash, along with Drs. Michael W. Young and Jeffrey C. Hall, were awarded the Nobel Prize in Physiology or Medicine in recognition of their cloning of circadian rhythm genes, and the elucidation of the biochemical mechanisms by which the circadian rhythm protein products regulated behavior. Benzer was at the forefront of the study of neurodegeneration in fruit flies, modeling human diseases and attempting to suppress them. He also contributed to the field of aging biology, looking for mutants with altered longevity and trying to dissect the mechanisms by which an organism can escape the inevitable functional downfall and its associated diseases. In 1998, Benzer and his colleagues Yi Jyun Lin and Laurent Seroude published findings of a long life mutant in Drosophila, then named Methuselah. The mutant gene coded for a previously unknown member of the GPCR family. By testing against temperature stress, it is thought that these mutants have an increased ability to respond to stress and thus to live longer. One of Benzer's final research projects was on dietary restriction and longevity research. A paper was published, in ''Cell'', on the longevity effect of 4E BP, a translational repressor, following dietary restriction. Although the research was done before his death, the paper was published afterwards and dedicated to his memory.