Spelled Out: What it is to be Human

Scientists have reached a landmark point in one of the world's most important scientific projects by sequencing the last chromosome in the human genome, the so-called "book of life". [Image: False-color photograph showing human chromosomes, with the Chromosome 1 pair highlighted in blue. Indigo Instruments / Wellcome Trust Sanger Center]

Packed with 3,141 genes and linked to 350 illnesses including cancer, Alzheimer's and Parkinson's diseases, the important but mysterious chromosome number 1 comprises eight percent of the human genetic code, containing nearly twice as many genes as the average human chromosome.

The entire human genome contains somewhere between 20,000 and 25,000 genes divided up unevenly between 23 pairs of chromosomes; one complete set of chromosomes is donated by each parent. The completion of the chromosome one sequence has added more than 1,000 new genes to our databases.

Each chromosome is a large molecule of Deoxyribonucleic Acid (DNA) that is tightly coiled and highly compressed into a chromosome. DNA is a long thread-like structure comprised of a two smaller strands that twist around each other in a "double helix" structure. These DNA strands are made up of four chemical bases represented by the letters A (adenine), T (thymine), G (guanine) and C (cytosine). The specific arrangement, or "sequence", of these four bases along the length of a DNA strand defines every gene's special genetic code.

Chromosome one is the largest human chromosome, comprised of an estimated 245,203,898 bases. It took 10 years of work by a team of 150 British and American scientists to completely sequence the human genome.

As a result of the Human Genome Project, scientists have already identified 4,500 new SNPs, or "single nucleotide polymorphisms", which are seemingly harmless variations in human DNA sequences that make people genetically unique. SNPs are now known to contain clues that can help scientists to determine the best way to diagnose and treat such diseases and to predict how these diseases will respond to particular treatment regimes.

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What it is to be a Homo sapiens. Not what it is to be a human being.

By chardyspal (not verified) on 17 May 2006 #permalink

Yeah, it would be hard to write this sloppy tragicomedy with only four letters. Unless those four letters are . . . nevermind. Still, this is really cool info about what it is to be the third chimp.

Those two chromosomes in the top center right look like thy've... melded and grown together! Oh dear god! The humanity! What kind of twisted desease is this?!

Of course, I'm not a biologist...