Genome size

Genome size has been calculated for a variety of flatworm species (seeTable 2.3 for summary data and references). 

For theTrematoda and Cestoda, both reassociation kinetics/Cot analysis and direct measurement of the DNA content of Feulgen-stained nuclei have been used to estimate genome size. As relatively few taxa have been examined, it is difficult to draw any firm conclusions although the available data suggest much less extreme variation than in the Turbellaria and the absence of step-like intrageneric variation (Table 2.3). 

Taxonab Haploid genome size0 Picograms Megabases Reference 

Several determinations of the amounts of the different types of DNA have been made in avian 

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Genome. size fs given a.s millions ofba.se pairs (mb). ... 

Yeast (Saeeharomyees eerevisiae) has a genome size of 1.21 X 10 bp. If a genomic library of yeast DNA was constructed in a bacteriophage A vector capable of carrying 16-kbp inserts, how many indi-... 

Gem, see Geminal, 705 Geminal (gem), 705 Genome, size of in humans. 1107 Gentamicin, structure of, 1002 Geraniol, biosynthesis of, 382 Geranyl diphosphate, biosynthesis of, 1077-1078... 

Grime, J.P. Mowforth, M.A. (1982). Variation in genome size - an ecological interpretation. Nature, 299, 151-3. 

VN cell body zone Projection site of VN axons Gene category Genome size (%) Chemosignal molecules GPCR variant Ion channel... 

Organism Genome size [Mbp]/ gene number /% in COCsf Clinical disease or syndrome... 

Spirochetes (B. burgdorferi, T. pallidum) Related pathogens with reduced genome sizes, with drastic differences in their signal transduction apparatus, and unique sets of surface molecules... 

The number of genes annotated in this genome is unusually large given the genome size. Thus we suspect that many of the annotated open reading frames are not real genes, which results in an unexpectedly low rate of fold prediction. 

Genome size does not directly reflect the complexity of organisms... 

There is no simple correlation between organismal complexity and genome size. 

For a more complete listing of genomic sizes, see www.genomics.com/statistics.php. 

Johnston JS, Pepper AE, Hall AE, Chen ZJ, Hodnett G, Drabek J, Lopez R, Price HJ (2005) Ev olution of genome size in Brassicaceae. Ann Bot 95 229-235... 

Table 2.1. Genome size (expressed as the number of nucleotide base pairs present in the entire genome of various microorganisms whose genome sequencing is complete/near complete). MB (megabase) = million bases...

Microbe Genome size (MB) Microbe Genome size (MB)... 

Mushegian and Koonin (1996) calculated an inventory of 256 genes that represents the amount of DNA required to sustain a modern type of minimal cell under permissible conditions. This number, as indicated later by Koonin (2000), is quite similar to the values of viable minimal genome sizes inferred by site-directed gene disruptions in B. subtilis (Itaya, 1995) and transposon-mediated... 

Figure 11.5 Prokaryotic genome size distribution (N = 641). Open boxes, free-living prokaryotes grey boxes, obligate parasites black boxes, thermophiles boxes with horizontal lines, endosymbionts. (Modified from Islas etal, 2004.)...

Let us now come back to nature as it is, and look at the size of the smallest organisms. Figure 11.5 compares the genome size distribution, calculated under a series of assumptions (Islas etal., 2004), of free-living prokaryotes, obligate parasites, thermophiles, and endosymbionts. The values of DNA content of free-hving... 

Proteome Genome size (kb) Number of ORFs Number of redundant sequences Redundancy (%)... 

Genome sizes, complete proteomes, and the number of open reading frames (ORFs) were all retrieved from http //www.ncbi.nlm.nih.gov. Taken, with permission, from Islas et al., 2004. 

Itaya, M. (1995). An estimation of the minimal genome size required for life. FEES Lett., 362, 257-60. 

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