Download Prokaryotic genomes

MICROBIOLOGIA GENERALE
Prokaryotic genomes
The prokaryotic genome
Essential and non-essential genes in the prokaryotic genome
The prokaryotic genome
The chromosome of Escherichia coli
The chromosome of Escherichia coli
Autoradiograph of intact replicating chromosome of
Escherichia coli
Supercoiled DNA
Prokaryotic genomes:
Sequencing, sizes, ORF
contents and gene
distributions
Whole-genome random sequencing
and assembly of Haemophilus
influenzae Rd
Fleischmann et al. Science 269, 469-512, 1995
An approach for genome analysis based on sequencing and assembly of
unselected pieces of DNA from the whole chromosome has been applied
to obtain the complete nucleotide sequence (1,830,137 base pairs) of the
genome from the bacterium Haemophilus influenzae Rd. This approach
eliminates the need for initial mapping efforts and is therefore applicable to
the vast array of microbial species for which genome maps are
unavailable. The H. influenzae Rd genome sequence (Genome Sequence
DataBase accession number L42023) represents the only complete
genome sequence from a free-living organism.
H. influenzae DNA was sonicated
and fragments with sizes between
1.6 and 2.0 kb purified from an
agarose gel and ligated into a
plasmid vector to produce a clone
library. End sequences were
obtained from clones taken from
this library, and a computer used
to identify overlaps between
sequences. This resulted in 140
sequence contigs, which were
assembled into the complete
genome sequence,
The steps in a whole-genome shotgun sequencing project
Locating possible functional open reading frames (ORFs)
This is a schematic representation of the Escherichia coli O157:H7 EDL933 DNA
molecule: chromosome Escherichia coli O157:H7 EDL933. Each color represents a
different functional group of genes.
Prokaryotic genomes
Microorganism
Size (bp)
ORFs
Mycoplasma genitalium
Borrelia burgdorferi
Treponema pallidum
580 070
910 725
1 138 006
470
853
1041
Helicobacter pylori
Staphylococcus aureus
Bacillus subtilis
Mycobacterium tuberculosis
Escherichia coli
Pseudomonas aeruginosa
Streptomyces coelicolor
1 667 867
2 814 816
4 214 810
4 411 529
4 639 221
6 264 403
8 667 507
1590
2593
4100
3924
4288
5570
7846
Total ORFs in genome
Correlation between genome size and ORF content in prokaryotes
Genome size (megabases)
Each megabase of prokaryotic DNA encodes about 1000 ORFs
Gene function in bacteria genomes
Functional category of genes as a relative percent of the
genome versus total ORFs in the genome
Variations in gene category in Bacteria and Archea
Eukaryotic genomes
Organism
Saccharomyces cerevisiae
Plasmodium falciparum
Encephalitozoon cuniculi
Caenorhabditis elegans
Arabidopsis thaliana
Mus musculus
Homo sapiens
Size (Mbp)
ORFs
13 (16 chr)
27 (14 chr)
2.9 (11 chr)
5570
1997
97 (6 chr)
19099
125 (5 chr)
2500 (23 chr)
3000 (23 chr)
25498
30000
30000?
Eukaryotic genomes
http://www.ncbi.nlm.nih.gov/genomes/MICRO
BES/microbial_taxtree.html
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