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Download Prokaryotes vs Eukaryotes
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Prokaryotes vs Eukaryotes genome size Prokaryotes Eukaryotes 500 kb-10 Mb 4 Mb-several Gb protein coding genes 500-5000 4000-40000 introns groupII, rare very common domains per gene 1 1 to many Genome Evolution spontaneous mutations gene duplications, gene family expansions segmental duplications genome duplications (initially polyploidy) lateral gene transfer transposon insertions loss of not required information (extreme: obligate parasites) Genome Sizes of Sequenced Prokaryotes from: Handbook of Comparative Genomics, Fig. 1.2 Genomic Features of Sequenced Eukaryotes DM CE 97 SC 12 AT 125 DD 34 HS Size [Mb] 120 Genes # 14,000 19,000 6,000 25,000 10,000 35,000 Repeats % 3 6 1 10 10 46 finished 2000 1998 1996 2000 2002/3 2003 3000 C-Value Paradox Mycoplasma Bacteria E. coli yeast Fungi Protists Plants Drosophila Insects Mollusks shark Cartilagenous Fish Bony Fish frog Amphibians Reptiles Birds human Mammals 105 bean lily 106 107 108 109 1010 number of nucleotides per haploid genome 1011 fern 1012 Junk DNA potential junk: introns repetitive elements intergenic regions parts of telomer and centromer structures ¾all parts of a genome for which a clear function is not yet defined Percentage of 'Junk' in the Human Genome 45 % 53 % 21 % 34 % 42 % 48 % LINEs SINEs retroviral-like DNA-only transposon 'fossils' segmental duplications simple repeats REPEATS 66 % 92 % 90.5% 100 % introns protein coding genes heterochromatin UNIQUE Undefined Repetitive Elements Movement Key Genes DNA transposon Transposase as DNA excission/replication RNA transposon LTR non-LTR AAAAA Reverse Transcriptase, Integrase as RNA intemediate Reverse Transcriptase/ Endonuclease as RNA intemediate Transposon Clusters Repetitive elements are often found as clusters ¾Restrictions for insertion exist! LINE Transposition Premature termination results in truncated elements in the genome Also transposition to double strand breaks possible Potential Role of Junk DNA repair of double strand breaks (Nature Genetics 2002,2 159-165) Genomic resistance against virus attacks regulatory units nuclear attachment sites structure forming sites locally hairpin, trefoil, knots, etc chromosome condensation Double Strand Repair Using Transposons Break Reverse Transcriptase can also use other polyA RNAs
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