文档介绍：Genomics and Its Impact
on Medicine and Society
A 2001 Primer
. Department of Energy Human Genome Program: is
DNA in the human genome is arranged
The Basics into 24 distinct chromosomes—physically
Cells are the fundamental working units separate molecules that range in length from
of every living system. All the instructions needed about 50 million to 250 million base pairs. A
to direct their activities are contained within few types of major chromosomal abnormalities,
the chemical DNA (deoxyribonucleic acid). including missing or extra copies or gross
DNA from anisms is made up of breaks and rejoinings (translocations), can be
the same chemical and ponents. detected by microscopic examination. Most
The DNA sequence is the particular side-by- changes in DNA, however, are more subtle and
side arrangement of bases along the DNA require a closer analysis of the DNA molecule
strand (., GGA). This order spells out to find perhaps single-base differences.
the exact instructions required to create a Each chromosome contains many genes,
anism with its own unique traits. the basic physical and functional units of
The genome is anism’plete heredity. Genes are specific sequences of bases
set of DNA. Genomes vary widely in size: the that encode instructions on how to make
smallest known genome for a free-an- proteins. prise only about 2% of the
ism (a bacterium) contains about 600,000 human genome; the remainder consists of
DNA base pairs, while human and mouse noncoding regions, whose functions may
genomes have some 3 billion. Except for mature include providing chromosomal structural
red blood cells, all human cells contain - integrity and regulating where, when, and in
plete genome. what quantity proteins are made. The human
genome is estimated to contain
30,000 to 40,000 genes.
Although genes get a lot of
attention, it’s the proteins that
perform most life functions and
even make up the majority of
cellular structures. Prot