Gregor Johann Mendel

Gregor Johann Mendel (July 20, 1822 – January 6, 1884) was an Austrian scientist and Augustinian friar who gained posthumous fame as the founder of the new science of genetics.

Gregor Johann Mendel

Between 1856 and 1863 Mendel cultivated and tested some 29,000 pea plants (i.e., Pisum sativum). This study showed that one in four pea plants had purebred recessive alleles, two out of four were hybrid and one out of four were purebred dominant. His experiments led him to make two generalizations, the Law of Segregation and the Law of Independent Assortment, which later became known as Mendel's Laws of Inheritance.

It was not until the early 20th century that the importance of his ideas was realized. By 1900, research aimed at finding a successful theory of discontinuous inheritance rather than blending inheritance led to independent duplication of his work by Hugo de Vries and Carl Correns, and the rediscovery of Mendel's writings and laws.

Hugo Marie de Vries (February 16, 1848, Haarlem – May 21, 1935, Lunteren) was a Dutch botanist and one of the first geneticists.

it is thought probable that de Vries did not understand the results he had found until after reading Mendel.Though Erich von Tschermak was originally also credited with rediscovery, this is no longer accepted because he did not understand Mendel's laws. Though de Vries later lost interest in Mendelism, other biologists started to establish genetics as a science.

Carl Erich Correns (September 10, 1864 - February 14, 1933) was a German botanist and geneticist.

Johannes Friedrich Miescher

Johannes Friedrich Miescher (13 August 1844, Basel – 26 August 1895, Davos) was a Swiss physician and biologist. He was the first researcher to isolate and identify nucleic acid.Miescher isolated various phosphate-rich chemicals, which he called nuclein (now nucleic acids), from the nuclei of white blood cells in 1869 at Felix Hoppe-Seyler's laboratory at the University of Tübingen, Germany, paving the way for the identification of DNA as the carrier of inheritance.

Archibald Edward Garrod

Sir Archibald Edward Garrod (25 November 1857 – 28 March 1936) was an English physician who pioneered the field of inborn errors of metabolism.Garrod studied the recurrence patterns in several families, realized it followed an autosomal recessive pattern of inheritance, and postulated that it was caused by a mutation in a gene encoding an enzyme involved in the metabolism of a class of compounds called alkaptans. He published The Incidence of Alkaptonuria: a Study in Chemical Individuality in 1902.

Walter Stanborough Sutton

Walter Stanborough Sutton was an American geneticist and physician whose most significant contribution to present-day biology was his theory that the Mendelian laws of inheritance could be applied to chromosomes at the cellular level of living organisms.The German biologist Theodor Bovei independently reached the same conclusions as Sutton in 1902 , and their concepts are often referred to as the Boveri-Sutton chromosome theory.

Walter Stanborough Sutton (April 5, 1877 - November 10, 1916)

Wilhelm Weinberg

Dr Wilhelm Weinberg (Stuttgart, December 25, 1862 – Tübingen, November 27, 1937) was a German half-Jewish physician and obstetrician-gynecologist, practicing in Stuttgart, who in a 1908 paper (Jahresheft des Vereins für vaterländische Naturkunde in Württemberg (Annals of the Society of the National Natural History in Württemberg) published in German, expressed the concept that would later come to be known as the Hardy-Weinberg principle.

Godfrey Harold Hardy

Godfrey Harold “G. H.” Hardy (7 February 1877 – 1 December 1947) was a prominent English mathematician, known for his achievements in number theory and mathematical analysis.Hardy is also known for formulating the Hardy–Weinberg principle, a basic principle of population genetics, independently from Wilhelm Weinberg in 1908. He played cricket with the geneticist Reginald Punnett who introduced the problem to him, and Hardy thus became the somewhat unwitting founder of a branch of applied mathematics.

Weinberg developed the principle of genetic equilibrium independently of British mathematician G.H. Hardy. He delivered an exposition of his ideas in a lecture on January 13, 1908, before the Verein für vaterländische Naturkunde in Württemberg (Society for the Natural History of the Fatherland in Württemberg), about six months before Hardy's paper was published in English. His lecture was printed later that year in the society's yearbook.Weinberg's contributions were unrecognized in the English speaking world for more than 35 years. Curt Stern, a German scientist who immigrated to the United States before World War II, pointed out in a brief paper in Science that Weinberg's exposition was both earlier and more comprehensive than Hardy's.Before 1943, the concepts in genetic equilibrium that are known today as the Hardy-Weinberg principle had been known as "Hardy's law" or "Hardy's formula" in English language texts.p^2(MM) + 2pq(MN) + q^2(NN) = ( p + q )^ 2 = 1

Thomas Hunt Morgan

Thomas Hunt Morgan (September 25, 1866 – December 4, 1945) was an American evolutionary biologist, geneticist and embryologist and science author who won the Nobel Prize in Physiology or Medicine in 1933 for discoveries relating the role the chromosome plays in heredity

Around 1908 Morgan started working on the fruit fly Drosophila melanogaster, and encouraging students to do so as well. With Fernandus Payne, he mutated Drosophila through physical, chemical, and radiational means. He began cross-breeding experiments to find heritable mutations, but they had no significant success for two years.Castle had also had difficulty identifying mutations in Drosophila, which were tiny. Finally in 1909, a series of heritable mutants appeared, some of which displayed Mendelian inheritance patterns

In 1910 Morgan noticed a white-eyed mutant male among the red-eyed wild types. When white-eyed flies were bred with a red-eyed female, their progeny were all red-eyed. A second generation cross produced white-eyed males—a sex-linked recessive trait, the gene for which Morgan named white. Morgan also discovered a pink-eyed mutant that showed a different pattern of inheritance. In a paper published in Science in 1911, he concluded that (1) some traits were sex-linked, (2) the trait was probably carried on one of the sex chromosomes, and (3) other genes were probably carried on specific chromosomes as well.

Alfred Henry Sturtevant

Alfred Henry Sturtevant (November 21, 1891 – April 5, 1970) was an American geneticist. Sturtevant constructed the first genetic map of a chromosome in 1913.He determined that genes were arranged on chromosomes in a linear fashion, like beads on a necklace. He also showed that the gene for any specific trait was in a fixed location (locus).

Calvin Blackman Bridges

Calvin Blackman Bridges (January 11, 1889 – December 27, 1938) was an American scientist . He wrote a masterful Ph.D. thesis on "Non-disjunction as proof of the chromosome theory of heredity." It appeared as the first paper in the first issue of the journal Genetics in 1916.

Hermann Joseph Muller

Hermann Joseph Muller (or H. J. Muller) (December 21, 1890 – April 5, 1967) was an American geneticist, educator, and Nobel laureate best known for his work on the physiological and genetic effects of radiation (X-ray mutagenesis) as well as his outspoken political beliefs.In 1923, he began using radium and X-rays

Harriet Baldwin Creighton (27 June 1909 – January 9, 2004)

Barbara McClintock (June 16, 1902 – September 2, 1992)

Barbara McClintock worked in the field of maize cytogenetics with Harriet Creighton, the pair published a very influential paper in 1931 in which they described chromosomal crossover for the first time. This paper, part of her Ph.D. research, provided key evidence that chromosomes carried and exchanged genetic information and hence that 'genes' for physical traits are carried on chromosomes.

George Wells Beadle

George Wells Beadle (October 22, 1903 – June 9, 1989) was an American scientist in the field of genetics, and Nobel Prize in Physiology or Medicine Nobel laureate who with Edward Lawrie Tatum (December 14, 1909 – November 5, 1975) discovered the role of genes in regulating biochemical events within cells.

George Wells Beadle

Beadle and Tatum's key experiments involved exposing the bread mold Neurospora crassa to x-rays, causing mutations. In a series of experiments, they showed that these mutations caused changes in specific enzymes involved in metabolic pathways. These experiments, published in 1941, led them to propose a direct link between genes and enzymatic reactions, known as the "one gene, one enzyme" hypothesis.

Oswald Theodore Avery

Oswald Theodore Avery (October 21, 1877 – February 2, 1955) was a Canadian-born American physician and medical researcher. Avery was one of the first molecular biologists and a pioneer in immunochemistry.The Nobel laureate Arne Tiselius said that Avery was the most deserving scientist not to receive the Nobel Prize for his work.

Colin Munro MacLeod (January 28, 1909 — February 11, 1972)

Maclyn McCarty ( June 9, 1911 – January 2, 2005)

The Avery–MacLeod–McCarty experiment was an experimental demonstration, reported in 1944 by Oswald Avery, Colin MacLeod, and Maclyn McCarty, that DNA is the substance that causes bacterial transformation.Induction of Transformation by a Deoxyribonucleic Acid Fraction Isolated from Pneumococcus Type III", published in the February 1944 issue of the Journal of Experimental Medicine, Avery and his colleagues suggest that DNA, rather than protein as widely believed at the time, may be the hereditary material of bacteria, and could be analogous to genes and/or viruses in higher organisms.The experimental findings of the Avery–MacLeod–McCarty experiment were quickly confirmed, and extended to other hereditary characteristics besides polysaccharide capsules.

James Dewey Watson

James Dewey Watson (born April 6, 1928) is an American molecular biologist, geneticist, and zoologist, best known as one of the co-discoverers of the structure of DNA in 1953 with Francis Crick.

Francis Harry Compton Crick

Francis Harry Compton Crick (8 June 1916 – 28 July 2004) was an English molecular biologist, biophysicist, and neuroscientist, and most noted for being one of two co-discoverers of the structure of the DNA molecule in 1953.

In March 1953, Watson and Crick deduced the double helix structure of DNA.Sir Lawrence Bragg, the director of the Cavendish Laboratory (where Watson and Crick worked), made the original announcement of the discovery at a Solvay conference on proteins in Belgium on April 8, 1953; it went unreported by the press. Watson and Crick submitted a paper to the scientific journal Nature, which was published on April 25, 1953. This has been described by some other biologists and Nobel laureates as the most important scientific discovery of the 20th century. Bragg gave a talk at the Guys Hospital Medical School in London on Thursday, May 14, 1953, which resulted in an article by Ritchie Calder in the newspaper The News Chronicle of London, on May 15, 1953, entitled "Why You Are You. Nearer Secret of Life."

Rosalind Franklin

Rosalind Elsie Franklin (25 July 1920 – 16 April 1958) was a British biophysicist and X-ray crystallographer who made critical contributions to the understanding of the fine molecular structures of DNA, RNA, viruses, coal and graphite.She died in 1958 at the age of 37 from complications arising from ovarian cancer.

Franklin, working with her student Raymond Gosling, started to apply her expertise in x-ray diffraction techniques to the structure of DNA. She used a new fine focus x-ray tube and microcamera ordered by Wilkins, but which she refined, adjusted and focused carefully.Crick and Watson then published their model in Nature on 25 April 1953 in an article describing the double-helical structure of DNA with only a footnote acknowledging "having been stimulated by a general knowledge of" Franklin and Wilkin's 'unpublished' contribution.

Weeks later, on 10 April, Franklin wrote to Crick for permission to see their model.Franklin retained her scepticism for premature model building even after seeing the Crick–Watson model, and remained unimpressed. She is reported to have commented, "It's very pretty, but how are they going to prove it?" As an experimental scientist Franklin seems to have been interested in producing far greater evidence before publishing-as-proven a proposed model. As such her response to the Crick–Watson model was in keeping with her cautious approach to science.However, as documented above, she did not hesitate to publish preliminary ideas about DNA in Acta, even before they could be definitively proven.

The rules of the Nobel Prize forbid posthumous nominations

and because Rosalind Franklin had died in 1958 at the age of 37 from complications arising from ovarian cancer. she was not eligible for nomination to the Nobel Prize subsequently awarded to Crick, Watson, and Wilkins in 1962.

Maurice Wilkins

Maurice Hugh Frederick Wilkins (15 December 1916 – 5 October 2004) was a New Zealand-born English physicist and molecular biologist.

Matthew Stanley Meselson

Matthew Stanley Meselson (born May 24, 1930) is an American geneticist and molecular biologist whose research was important in showing how DNA replicates, recombines and is repaired in cells. In his mature years, he has been an active chemical and biological weapons activist and consultant

Franklin William Stahl

Dr. Franklin William Stahl (born October 8, 1929) is an American molecular biologist. With Matthew Meselson, Stahl conducted the famous Meselson-Stahl experiment showing that DNA is replicated by a semiconservative mechanism, meaning that each strand of the DNA serves as a template for the "replicated" strand.

Karyogram of a human male