Biology Reference
In-Depth Information
mapped known genes on the physical structure of a chromosome, i.e., they related
physiological roles to genomic structures. Sequencing those parts of the DNA
that were identified as gene loci and consequently equaled with genes mainly
refines knowledge of the structure to which the physiological role is mapped.
Whole-genome sequencing, in contrast, focuses exclusively on the structure of
the genome. The assignment of physiological roles to substructures is now an
additional task. Some of the assignments can be read from gene maps. Others, so
the promise, can be inferred from the sequence (we will address the limitations
of this in the next paragraph).
With eukaryote genome projects, researchers did not concentrate on the easy
task, as initially with the prokaryotes, but shifted quickly to one for which large-
scale funding could be raised: the sequencing of the genome of
Homo sapiens
. The
human genome project promised to turn medicine into a straightforward techno-
logical application of biology within a short time (Drell & Adamson, 2000). Con-
siderable parts of the sequence were published simultaneously by the International
Human Genome Sequencing Consortium (2001) and Venter et al. (2001). Three
years later, the Consortium presented 99% of the human euchromatic sequence
(International Human Genome Sequencing Consortium, 2004). The sequence has
by now become an indispensable tool in different fields of biology. Comparison
with the genomic sequence of chimpanzee and gorilla genomes as well as with the
D. melanogaster
and
Caenorhabditis elegans
genomes provides important insights
into evolution, though not into the evolution of, e.g., cognitive capacities.
8
How-
ever, initial expectations that this project would yield medical applications ('genes
to drugs') within short time were soon frustrated, not really to the surprise of biol-
ogists who were aware that disease biology is complex, and that drug develop-
ment must be driven by insights into biological responses (Butcher et al., 2004).
At present, the complete knowledge of genomic data provides only very limited
insights into the physiology of an organism. Hence, it is of limited relevance for
explaining, say, diseases or the ontogeny of organisms. One reason is of course that
the physiological roles of DNA segments cannot be assumed to be easily readable
from the sequence, especially in eukaryotes, though the toolbox of bioinformatics
provides some help.
5.3. Early proteomic projects
Proteins, in contrast to genes, are individual macromolecules; hence structural
data need not be supplemented with knowledge about functions to compile
complete genomic sequence was published in 1995 (Fleischmann et al., 1995). The sequence of
E. coli
followed two years later (Blattner et al., 1997).
8
For a philosophical analysis of the way in which results from the projects concerning non-human organisms
are used to interpret human genome data see Ankeny (2001).
