The project has produced three key research tools that enable investigators to detect genes involved in normal biology as well as common and rare diseases. One such method is "positional cloning," enabling scientists to locate disease-linked genes by their genomic locations.
Scientists use various tools to study genomes, which contain 3 billion DNA building blocks. Their use has already revolutionized basic biological research as well as clinical medicine.
The Project’s Goals
This project's primary aim was to establish the order or sequence of all 3 billion DNA building blocks found within each chromosome, in order to allow scientists to locate genes, map regulatory regions that regulate gene activity and link structural DNA with function.
Researchers needed three major tools in order to accomplish their task of mapping DNA. The first, known as a genetic map, identifies landmarks--short pieces of DNA--more or less evenly spaced along a chromosome. The second tool called physical map orders collections of overlapping DNA which cover an entire chromosome before cloning enough copies in sufficient numbers to sequence. Finally, sequence maps combine information from both genetic and physical maps in order to locate specific genes.
Though faced with numerous challenges, HGP scientists managed to make significant strides forward. By the time of its completion in 2003, they had produced draft sequences for human beings as well as multiple model organisms like Escherichia coli bacteria, Drosophila melanogaster fruit fly, Caenorhabditis elegans roundworm and mouse Mus musculus mice. Furthermore, this project contributed new methods of DNA analysis such as genome mapping, finding individual genes sequence DNA sequencing DNA manipulation using computers and more extensive computer manipulation of genomic data manipulation capabilities.
As a result of the HGP, many different research laboratories now have access to an abundance of information about human body. Researchers can use this data to understand how genes influence traits and develop new drugs or therapies targeting specific cellular mechanisms or biochemical pathways. Furthermore, this initiative introduced a new era of "omics", in which molecular and genomic techniques are combined with statistical approaches in order to examine complex biological systems such as whole organisms or ecosystems.
As early as its first days, HGP researchers faced one significant social impact of genome research which remains an issue today: this controversy surrounding its social implications. Some people argued that HGP research was bad science because it diverted resources away from "real" small science such as single investigator research; that sequencing the human genome would cost too much; or it tipped biology toward technocracy. While this debate continues today, recent technological advancements have drastically transformed biology.
The Project’s Methods
At the outset of their project, scientists were uncertain how best to approach sequencing the human genome. So they decided to sequence model organisms' genomes, such as yeast, Arabidopsis thaliana plants (a small flowering plant), roundworms and fruit flies first in order to gain experience and foster a collaborative spirit that would prepare them to tackle more complex task of sequencing human genes later.
Next, scientists created both genetic and physical maps of these model organisms' genomes. For a genetic map, researchers placed polymorphic markers at specific positions on their genomes in order to locate genes of interest. Physical maps were drawn by aligning contigs from across individual chromosomes using genetic maps as mileposts.
At the outset of the project, sequencing of the human genome was anticipated to take months; however, due to advances in biotechnology during this project, sequencing a gene could now take only hours!
HGP researchers created another key tool, positional cloning, enabling investigators to directly locate disease-linked genes within the genome without first needing to ascertain their function. This technique proved indispensable in discovering genes linked to chronic granulomatous disease as well as many other common disorders.
HGP researchers have also been conducting extensive analyses on non-coding DNA found within human genome, to better understand its purposes other than protein coding; their studies indicate that much of this DNA plays a key role in gene regulation and host functions.
HGP stands out for its impact on scientific collaboration. The massive undertaking brought scientists from all around the world together, showing what can be accomplished when working collaboratively as one unit. Furthermore, this project raised awareness of research ethics issues related to genetically modifying humans.
The Project’s Results
Researchers have gained much from this project, particularly by expanding their understanding of how genes operate. This knowledge is having ripple effects through basic biological research and clinical medicine - for instance, scientists can now easily locate and function many human genes which allows them to develop novel strategies for preventing disease or treating those living with genetic disorders.
Scientists use this sequence of proteins as a valuable source of knowledge about human evolution and development, comparing modern humans with Neanderthals in order to understand how genes have changed over time.
As soon as the project began in 1990, some critics raised serious doubts as to its value. Some complained of "big science," diverting resources away from "real" small science such as individual investigator work; that most of what the genome contained wasn't worth studying and mapping and sequencing it would require large teams of scientists for optimal performance.
Ultimately, however, the project was successful and completed two years early; in 2000, National Institutes of Health (NIH) and Sanger Centre announced their first draft human genome sequence. Although NIH and Sanger Centre were the main players, Celera completed its genome sequence using different techniques; both groups succeeded in producing an initial draft version within months of each other - Celera doing so slightly earlier than NIH & Sanger Center.
Since completing the project, scientists have continued to build upon its discoveries. Greg Findlay's team at the Francis Crick Institute in UK have been exploring how certain variants in tumor suppressor genes increase our risk of cancer development; and they are also trying to understand what other functions our DNA might serve.
Genomics is helping researchers easily identify and study rare diseases. Over time, genomics may even lead to new therapies that go beyond treating symptoms directly; instead targeting their source by identifying genetic mutations within our DNA. But the ultimate goal should be understanding our entire genetic instruction set so we can use it effectively against disease prevention or cure development.
The Project’s Impact
The Human Genome Project revolutionized scientific practices. Its leaders agreed to make all parts of its draft sequence available publicly shortly after production, encouraging scientists to collaborate in its analysis. As a result, its publication revolutionized microbiology and plant biology fields alike while inspiring similar projects focused on other organisms' genome sequences.
Before the Human Genome Project (HGP), scientists had already deciphered some base sequences of individual genes; however, most of the genome remained unknown. Through HGP, scientists were able to increase the speed with which genetic information was discovered: by March 1999, a consortium announced it had produced a "working draft" sequence of the human genome; then by April 2003 they declared it completed (Pennisi and Wadman).
This new sequence offered many insights into gene function, but even more significant were the genetic maps created by researchers to assist them in pinpointing specific genes within chromosomes. These maps contain thousands of DNA landmarks that are more or less evenly spaced across chromosomes; using these landmarks allows investigators to narrow the search down to just a region before turning to physical maps (sets of DNA segments that cover an entire chromosome) as an additional tool to further pinpoint this gene of interest.
These new genetic, physical and sequence maps will not only advance basic biological research but will be essential in unraveling complex disorders caused by multiple genes and environmental influences such as diabetes; cardiovascular disease (including stroke and atherosclerosis); cancer; and mental illnesses like depression or alcoholism.
Scientists are only just beginning to explore the full potential of our genome sequence, yet. It may take us years before we understand how the thousands of genes contribute to the various complex aspects of health and wellbeing, while simultaneously protecting against any misinterpretations that reduces all characteristics to mere genetic explanations; such misreading can have harmful repercussions, including social discrimination based on genetic makeup and undervaluing natural variation among human traits.
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