Download Genes and genomes

A gene is a particular sequence (a string) of
nucleotides on a particular site of a
chromosome. It is made up of combinations
of A, T, C, and G. These unique combinations
code for a particular amino acid, much as
letters join together to form words.
A chromosome is nature’s great packaging
experiment – it contains tightly coiled DNA
around special proteins. The DNA of a human
being’s 23 chromosomes, when uncoiled, is 2
meters long!!
A genome is made up of all of the DNA in an
organism’s chromosomes—it is all of its genetic
information.
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An analogy to the human genome stored on
DNA is that of instructions stored in a library.
The library would contain
46 books (chromosomes).
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The books range in size from 400 to 3340
pages (genes), which is 48 to 250 million
letters (A,C,G,T) per book.
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So, the library contains over six billion letters
total;
The library fits into a cell nucleus the size of
a pinpoint;
A copy of the library (all 46 books) is
contained in almost every cell of our body.
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A 13-year project (1990-2003) that
discovered all estimated 20,000 to 25,000
human genes.
The project also discovered the complete
sequence of all 3 billion DNA bases (A,T,C,G).
All the information in
stored in databases.
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Why bother? Just a few reasons….
Improved disease diagnosis
Determining genetic predisposition to disease
Developing gene therapy
Designing custom drugs