The history of genetics can be represented on a timeline of events from the earliest work in the 1850s, to the DNA era starting in the 1940s, and the genomics era beginning in the 1970s.
Early timeline
1856–1863: Mendel studied the inheritance of traits
between generations based on experiments involving garden pea plants.
He deduced that there is a certain tangible essence that is passed on
between generations from both parents. Mendel established the basic principles of inheritance, namely, the principles of dominance, independent assortment, and segregation.
1869: Friedrich Miescher discovers a weak acid in the nuclei of white blood cells that today we call DNA. In 1871 he isolated cell nuclei, separated the nucleic cells from bandages and then treated them with pepsin (an enzyme which breaks down proteins). From this, he recovered an acidic substance which he called "nuclein".
1889: Richard Altmann purified protein free DNA. However, the nucleic acid was not as pure as he had assumed. It was determined later to contain a large amount of protein.
1889: Hugo de Vries postulates that "inheritance of specific traits in organisms comes in particles", naming such particles "(pan)genes".
1902: Archibald Garrod
discovered inborn errors of metabolism. An explanation for epistasis is
an important manifestation of Garrod's research, albeit indirectly.
When Garrod studied alkaptonuria, a disorder that makes urine quickly
turn black due to the presence of gentisate, he noticed that it was
prevalent among populations whose parents were closely related.
1903: Walter Sutton and Theodor Boveri independently hypothesizes that chromosomes, which segregate in a Mendelian fashion, are hereditary units; see the chromosome theory. Boveri was studying sea urchins when he found that all the chromosomes in the sea urchins had to be present for proper embryonic development
to take place. Sutton's work with grasshoppers showed that chromosomes
occur in matched pairs of maternal and paternal chromosomes which
separate during meiosis. He concluded that this could be "the physical basis of the Mendelian law of heredity."
1908: G.H. Hardy and Wilhelm Weinberg proposed the Hardy–Weinberg equilibrium model
which describes the frequencies of alleles in the gene pool of a
population, which are under certain specific conditions, as constant and
at a state of equilibrium from generation to generation unless specific
disturbing influences are introduced.
1910: Thomas Hunt Morgan shows that genes reside on chromosomes while determining the nature of sex-linked traits by studying Drosophila melanogaster.
He determined that the white-eyed mutant was sex-linked based on
Mendelian's principles of segregation and independent assortment.
1911: Alfred Sturtevant, one of Morgan's collaborators, invented the procedure of linkage mapping which is based on the frequency of crossing-over.
1913: Alfred Sturtevant makes the first genetic map, showing that chromosomes contain linearly arranged genes.
1920: Lysenkoism
Started, during Lysenkoism they stated that the hereditary factor are
not only in the nucleus, but also in the cytoplasm, though they called
it living protoplasm.
1930s–1950s: Joachim Hämmerling conducted experiments with Acetabularia
in which he began to distinguish the contributions of the nucleus and
the cytoplasm substances (later discovered to be DNA and mRNA,
respectively) to cell morphogenesis and development.
1931: Crossing over is identified as the cause of recombination; the first cytological demonstration of this crossing over was performed by Barbara McClintock and Harriet Creighton.
1933: Jean Brachet, while studying virgin sea urchin eggs, suggested that DNA is found in cell nucleus and that RNA is present exclusively in the cytoplasm.
At the time, "yeast nucleic acid" (RNA) was thought to occur only in
plants, while "thymus nucleic acid" (DNA) only in animals. The latter
was thought to be a tetramer, with the function of buffering cellular
pH.
1943: Luria–Delbrück experiment:
this experiment showed that genetic mutations conferring resistance to
bacteriophage arise in the absence of selection, rather than being a
response to selection.
1947: Salvador Luria discovers reactivation of irradiated phage, stimulating numerous further studies of DNA repair processes in bacteriophage, and other organisms, including humans.
1950: Erwin Chargaff determined the pairing method of nitrogenous bases. Chargaff and his team studied the DNA from multiple organisms and found three things (also known as Chargaff's rules). First, the concentration of the pyrimidines (guanine and adenine) are always found in the same amount as one another. Second, the concentration of purines (cytosine and thymine) are also always the same. Lastly, Chargaff and his team found the proportion of pyrimidines and purines correspond each other.
1955: Joe Hin Tjio,
while working in Albert Levan's lab, determined the number of
chromosomes in humans to be of 46. Tjio was attempting to refine an
established technique to separate chromosomes onto glass slides by
conducting a study of human embryonic lung tissue, when he saw that
there were 46 chromosomes rather than 48. This revolutionized the world
of cytogenetics.
1957: Arthur Kornberg with Severo Ochoa synthesized DNA in a test tube after discovering the means by which DNA is duplicated. DNA polymerase 1 established requirements for in vitro synthesis of DNA. Kornberg and Ochoa were awarded the Nobel Prize in 1959 for this work.
1957/1958: Robert W. Holley, Marshall Nirenberg, Har Gobind Khorana proposed the nucleotide sequence of the tRNA molecule. Francis Crick
had proposed the requirement of some kind of adapter molecule and it
was soon identified by Holey, Nirenberg and Khorana. These scientists
help explain the link between a messenger RNA nucleotide sequence and a polypeptide sequence. In the experiment, they purified tRNAs from yeast cells and were awarded the Nobel prize in 1968.
1960: Jacob and collaborators discover the operon, a group of genes whose expression is coordinated by an operator.
1961: Francis Crick and Sydney Brenner discovered frame shift mutations. In the experiment, proflavin-induced mutations of the T4 bacteriophage gene (rIIB) were isolated. Proflavin
causes mutations by inserting itself between DNA bases, typically
resulting in insertion or deletion of a single base pair. The mutants
could not produce functional rIIB protein. These mutations were used to demonstrate that three sequential bases of
the rIIB gene's DNA specify each successive amino acid of the encoded
protein. Thus the genetic code is a triplet code, where each triplet (called a codon) specifies a particular amino acid.
1966: Marshall W. Nirenberg, Philip Leder, Har Gobind Khorana
cracked the genetic code by using RNA homopolymer and heteropolymer
experiments, through which they figured out which triplets of RNA were translated into what amino acids in yeast cells.
1969: Molecular hybridization of radioactive DNA to the DNA of cytological preparation by Pardue, M. L. and Gall, J. G.
In the late 1970s: nonisotopic methods of nucleic acid labeling were
developed. The subsequent improvements in the detection of reporter
molecules using immunocytochemistry and immunofluorescence, in
conjunction with advances in fluorescence microscopy and image analysis,
have made the technique safer, faster and reliable.
1980: Paul Berg, Walter Gilbert and Frederick Sanger
developed methods of mapping the structure of DNA. In 1972, recombinant
DNA molecules were produced in Paul Berg's Stanford University
laboratory. Berg was awarded the 1980 Nobel Prize
in Chemistry for constructing recombinant DNA molecules that contained
phage lambda genes inserted into the small circular DNA mol.
1980: Stanley Norman Cohen and Herbert Boyer received first U.S. patent for gene cloning, by proving the successful outcome of cloning a plasmid
and expressing a foreign gene in bacteria to produce a "protein foreign
to a unicellular organism." These two scientist were able to replicate
proteins such as HGH, Erythropoietin and Insulin. The patent earned about $300 million in licensing royalties for Stanford.
1982: The U.S. Food and Drug Administration (FDA) approved the release of the first genetically engineered human insulin, originally biosynthesized using recombination DNA methods by Genentech in 1978. Once approved, the cloning process lead to mass production of humulin (under license by Eli Lilly & Co.).
1983: Barbara McClintock was awarded the Nobel Prize in Physiology or Medicine for her discovery of mobile genetic elements. McClintock studied transposon-mediated mutation and chromosome breakage in maize and published her first report in 1948 on transposable elements or transposons. She found that transposons
were widely observed in corn, although her ideas weren't widely granted
attention until the 1960s and 1970s when the same phenomenon was
discovered in bacteria and Drosophila melanogaster.
Display of VNTR allele lengths on a chromatogram, a technology used in DNA fingerprinting 1985: Alec Jeffreys announced DNA fingerprinting method. Jeffreys was studying DNA variation and the evolution of gene families in order to understand disease causing genes. In an attempt to develop a process to isolate many mini-satellites at
once using chemical probes, Jeffreys took x-ray films of the DNA for
examination and noticed that mini-satellite regions differ greatly from
one person to another. In a DNA fingerprinting technique, a DNA sample
is digested by treatment with specific nucleases or Restriction endonuclease and then the fragments are separated by electrophoresis producing a template distinct to each individual banding pattern of the gel.
1986: Jeremy Nathans found genes for color vision and color blindness, working with David Hogness, Douglas Vollrath and Ron Davis as they were studying the complexity of the retina.
1987: Yoshizumi Ishino discovers and describes part of a DNA sequence which later will be called CRISPR.
1989: Thomas Cech discovered that RNA can catalyze chemical reactions, making for one of the most important breakthroughs in molecular
genetics, because it elucidates the true function of poorly understood
segments of DNA.
1992: American and British scientists unveiled a technique for testing embryos in-vitro (Amniocentesis) for genetic abnormalities such as Cystic fibrosis and Hemophilia.
1993: Phillip Allen Sharp and Richard Roberts awarded the Nobel Prize for the discovery that genes in DNA are made up of introns and exons. According to their findings, not all the nucleotides on the RNA strand (product of DNA transcription) are used in the translation process. The intervening sequences in the RNA strand are first spliced out so that only the RNA segment left behind after splicing would be translated to polypeptides.
1994: The first breast cancer gene is discovered. BRCA I was discovered by researchers at the King laboratory at UC Berkeley in 1990 but was first cloned in 1994. BRCA II, the second key gene in the manifestation of breast cancer was discovered later in 1994 by Professor Michael Stratton and Dr. Richard Wooster.
1995: The genome of bacterium Haemophilus influenzae is the first genome of a free living organism to be sequenced.
1996: Alexander Rich discovered the Z-DNA, a type of DNA which is in a transient state, that is in some cases associated with DNA transcription. The Z-DNA form is more likely to occur in regions of DNA rich in cytosine and guanine with high salt concentrations.
2001: Francisco Mojica and Rudd Jansen
propose the acronym CRISPR to describe a family of bacterial DNA
sequences that can be used to specifically change genes within
organisms.
Francis Collins announces the successful completion of the Human Genome Project in 2003 2003: Successful completion of Human Genome Project with 99% of the genome sequenced to a 99.99% accuracy.
2003: Paul Hebert introduces the standardisation of molecular species identification and coins the term 'DNA Barcoding', proposing Cytochrome Oxidase 1 (CO1) as the DNA Barcode for Animals.
2004: Merck introduced a vaccine for Human Papillomavirus which promised to protect women against infection with HPV 16 and 18, which inactivates tumor suppressor genes and together cause 70% of cervical cancers.
2007: Michael Worobey traced the evolutionary origins of HIV by analyzing its genetic mutations, which revealed that HIV infections had occurred in the United States as early as the 1960s.
2007: The Barcode of Life Data System (BOLD) is set up as an international reference library for molecular species identification.
2008: Houston-based Introgen developed Advexin (FDA Approval pending), the first gene therapy for cancer and Li-Fraumeni syndrome, utilizing a form of Adenovirus to carry a replacement gene coding for the p53 protein.
2009: The Consortium for the Barcode of Life Project (CBoL) Plant
Working Group propose rbcL and matK as the duel barcode for land plants.
2011: Fungal Barcoding Consortium propose Internal Transcribed Spacer region (ITS) as the Universal DNA Barcode for Fungi.
2012: The flora of Wales is completely barcoded, and reference
specimens stored in the BOLD systems database, by the National Botanic
Garden of Wales.
2016: A genome is sequenced in outer space for the first time, with NASA astronaut Kate Rubins using a MinION device aboard the International Space Station.
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