The Human Genome Project?

Genome sequencing technology has led to many recent scientific breakthroughs. These breakthroughs have captured the interest of the public and are being reported with excitement by both the media and scientific journals. The completion of the human genome project (HGP) is an example of newsworthy science that has the potential to have major effects on our society today. The HGP was an initiative started in the early 1990’s that has involved the efforts of hundreds of scientists to generate high-quality reference sequence for the 3 billion base pairs of nucleotide sequence that make up the human genome. The complete string of nucleotide letters that make up the DNA sequence in our cells is often referred to as our genome. This DNA sequence contained in a genome contains the complete code that determines which genes and proteins will be present in human cells. By reading the sequence of the human genome, scientists hope to gain an understanding of the underlying code that determines how a complex biological system, such as a human cell, acts and reacts. Insights from deciphering the human genome have potential to be applied to a better understanding of human health and could help to develop better treatments for disease.

What have we learned from the Human Genome Project?

These major accomplishments in genome sequencing provide a wealth of information that aid in the understanding of basic biological processes. With genome sequence in-hand scientists are now more effectively able to study gene function and explore new areas of research such as how human variation contributes to different diseases worldwide. Scientists today are discovering that the more we learn about the human genome, the more that there is to explore. For instance, as a first step in understanding the genomic code we have learnt that the human genome is made of 3.2 billion nucleotide bases (of which there are four types: A, C, T, G). It is thought that over 30,000 genes are encoded by this sequence. Yet we have also discovered that over 50% of the human genome is repetitive sequence that does not code for any proteins and the function of this large portion of “junk” DNA is still puzzling scientists. Along similar lines, the HGP has shown us that the average length of an expressed gene is 3000 bases long. Genome sequence information has helped scientists more easily identify candidate disease genes, however, we also realize that over 50% of the genes discovered in the human genome are still classified as having unknown function. Human genome sequence information reveals that genome sequences from person to person are almost (99.9%) identical. Interestingly, comparative genomics shows 95% sequence similarity between the human and chimpanzee genomes. Scientists are just beginning to understand how this small amount of variation contributes to differences in disease incidences in different populations. The discovery of about 3 million locations that have single base differences in the human genome (called single nucleotide polymorphisms or SNPs) offers insights into how genomic information could be used to discover information related to the incidence of common human traits, including susceptibility to certain diseases and illnesses.

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