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Armchair Genealogy
THE HUMAN GENOME PROJECT
Recent columns of Armchair Genealogy have provided basic background information of DNA, its discovery, significant application of those discoveries that further our use of the knowledge, and a very basic Glossary organized not alphabetically but logically to provide a framework for discussion. This column will focus on the Human Genome Project.
What prompted the creation of the project? How was it funded?
What were its goals? Who was involved? And, not the least important,
what does the Project's findings mean to us as family researchers?
First, we should revisit important milestones leading to mankind's discovery and desire to better understand DNA.
Historical Advances that Led to Discovery of DNA:
The discovery of DNA, the foundation for creation, had its
roots in theory. In 1831, Charles Darwin joined a scientific expedition
that studied fossils. His inspection of these fossils aroused his
interest, specifically, what caused the apparent improvement in
structure from one generation to the next? By 1859, Darwin could
articulate his theory: which could be called 'survival of the fittest'.
Darwin theorized some core element caused the change: the creature best
suited to survive in its habitat developed a mutation that could be
passed on to the next generation, thus changing the entire species until
the next adaptation occurred in response to some new challenge.
This theory was amplified by the studies of an Augustinian
monk, Gregor Mendel. Mendel undertook exhaustive experiments of pea
plants in a continuous study begun in 1859. Through his studies, Mendel
defined the terms of dominant and recessive traits in genetic
transformation.
"In his 1866 published paper, Mendel described the action of 'invisible' factors in providing for visible traits in predictable ways. We now know that the 'invisible' traits he had identified were genes."
In 1869, a groundbreaking discovery was made by Friedrich
Meischer, a Swiss physiological chemist seeking to isolate the protein
substances comprising white blood cells. In the process, he found a
substance with chemical properties quite different in composition to
those he had been studying. He described it as having "very high
phosphorus content and a resistance to protein digestion." The substance
was, in fact, deoxyribonucleic acid - DNA.
In 1900, Mendel's theory of dominant and recessive traits
being predictable but guided by some as yet unidentified underlying
factor generated studies by Hugo DeVries, a Dutch botanist and
geneticist; by Carl Erich Correns, German botanist and geneticist; and
Eric Tschermak von Seysenegg, an Austrian botanist. Using his
experiments as their basis, each reported hybridization experiment
results similar to his findings.
By 1902, Mendel's studies found substantiation in the efforts
of Sir Archibald Edward Garrod, an Oxford educated physician. In his
studies of families beset with Alcaptonuria, Garrod ascribed the high
incidence of familial inheritance of this rather rare disease to "inborn
errors of metabolism." Garrod discussed his beliefs with William
Bateson, a leading proponent of Mendellian theory. When Garrod published
his scientific study entitled 'The Incidence of Alcaptonuria: A Study
in Chemical Individuality' in 1902, that marked the first time recessive
inheritance traits in humans were ascribed to a molecular basis of
inheritance.
By 1944, scientists understood more about genetics. They had
accepted the fact genes formed the "discrete units of heredity" and that
they generated "enzymes that controlled metabolic functions." Oswald
Avery, a Canadian-American scientist and medical researcher, discovered
mixing a harmless form of live pneumococcus with an inert but lethal
form transformed the harmless bacteria into a deadly organism.
In concert with Colin MacLeod and Maclyn McCarty, Avery
carried out endless experiments in purifying collected bacteria. The
remaining substance was deemed neither protein nor carbohydrate, but a
nucleic acid, ultimately identified as DNA. The study they published
named DNA as the resulting in their conclusion: "the nature of DNA is
the transforming principle."
Avery's findings changed the course of study for another
scientist, Erwin Chargaff. He changed his focus to in-depth analysis of
the chemistry of nucleic acids. He first developed a method of analyzing
that identified the nitrogenous components and sugars of DNA from
different species. His research led to two major findings, published by
him in 1950, known today as Chargaff's Rules: 1) in any double stranded
DNA, the number of guanine units is equal to the number of cytosine
units and the number of adenine units is equal to the number of thymine
units, and 2) the composition of DNA varies between species.
These Rules have been indispensable in further studies of DNA.
1952 was of immense importance in the study of DNA. Rosalind
Franklin, a British woman who achieved a doctorate in physical chemistry
from Cambridge University then went on to learn x-ray diffraction
techniques. In 1951, working with scientist Maurice Wilkins and student
Raymond Gosling, she was able to produce two sets of high-resolution
photographs of DNA fibers. From these photos, Franklin calculated the
dimensions of the strands and deduced the phosphates were on the outside
of what was probably a helical structure. Between 1951 and 1953,
Rosalind Franklin came ever closer to identifying the structure of DNA.
That discovery, though based upon her photographs and basic
conclusions, was attributed to James Watson and Francis Crick. The duo
set out to study the structure of DNA at Cavendish Laboratory at
Cambridge University in 1951. Through use of x-ray data and model
building, they solved the puzzle that had baffled scientists for
decades. Their paper, published in April 1953 resulted in them being
awarded the Nobel prize in 1962 for physiology or medicine along with
Maurice Wilkins (the scientist with whom Franklin had worked.)
Additional advances were made in the study of DNA, techniques advancing the accessibility of actual DNA sequences, and discoveries of genetically linked diseases. All these made more and more scientists eager to delve into the study of DNA."Despite the fact that her photographs had been critical to Watson and Crick's solution, Rosalind Franklin was not honoured, as only three scientists could share the prize.
One significant discovery occurred in the late 1960s and early 1970s when stains such as Giemsa were found to
"bind to chromosomes in a non-uniform fashion, creating bands of light
and dark areas. The invention transformed the discipline, making it
possible to identify individual chromosomes, as well as sections within
chromosomes, and formed the basis of early clinical genetic diagnosis."
These advances made huge ripples in the scientific community.
Suddenly the study of DNA was in the forefront of news. Everyone was
now fascinated by the frequent news of the latest discoveries tying
genetic abnormalities to known human frailties and diseases: Down
Syndrome, Huntington's Disease, breast cancer. Interest was aroused in
having a government-funded project to advance the demystification of the
basis of life.
Timeline of The Human Genome Project:
1990: The Human Genome Project began and was funded by the
US Department of Energy and the National Institute of Health. It was
recommended in 1988, but officially started in 1990. Multiple purposes
existed for the initiation of this project, not only the advancement of
medicine, but for other purposes such as the detection of mutations that
nuclear radiation might cause.
"The project's goals included: mapping the human genome and determining all 3.2 billion letters in it, mapping and sequencing the genomes of other organisms, if it would be useful to the study of biology, developing technology for the purpose of analyzing DNA and studying the social, ethical and legal implications of genome research."
Next month's column will address the following subjects:
Significant Findings of The Human Genome Project:
What Remains to be Discovered?
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