g Genome the complexity of the o organIsm Genome size: the length of DNA associated with one haploid complement of chromosomes go > Gene number: the number of genes a included in a genome gene density: the average number of genes per Mb of genomic DNA See Table 7-2 to find the relationship 3/15/05
Chromosome sequence & diversity ➢ Genome size: the length of DNA associated with one haploid complement of chromosomes ➢ Gene number: the number of genes included in a genome ➢ Gene density: the average number of genes per Mb of genomic DNA Genome & the complexity of the organism See Table 7-2 to find the relationship 3/15/05
ABLE了2c。 paris。 n of the Gene Density in Different organisms Gen。s Genoe aize pproximate Gene densiy (MD) number of genes (gonewMb) PROKARYOTES (bacteria) Mycoplasma o58 6oo 86o genitalium StreptococcuS 2,30 1。6o pneumonia Escherichia coli 4.6 4.4 95o Agrobacterium 5,40 96o tumefaciens Sinorhizobium 93o me/loti EUKARYOTES (animals) Fung/ Saccharomyces 5,8oo 48o cerevisiae Schizosaccharomyces 4.9oO n。。z。 Tetrahymena 22o thermophila InverteBrates Caenorhabditis 19.oO 200 elegans Drosophila 18O 13.700 melanogaster Strongylocentrotus 845 ≥2,oOO 26 purpuratus L。 custa 5.Ooo migratoria Vertebrates Fugu rubripes 365 31.0OO 85 Homo sapiens 2 zoo 27.o00 Mus musculus 2.50o 290oo Arabidopsis the∥ana 125 25.50O 200 Oryza sativa (rice) 430 45.O00 ∠ ea mays 2.200 45.000 Fritillaria assyriaca 120.Oo0 1(tulip) Table 7-2
Table 7-2
a Genes make up only a small proportion of o the eukaryotic genome a> Increases in gene size: (1)increase n in the sequence of regulatory sequence;(2) presence of introns (splicing) 2 >Increases in the DNA between genes(intergenic sequences): (1) unique;( 2) repeated See Figure 7-2,3, 4, 5: Table 7-3 3/15/05
Chromosome sequence & diversity ➢ Increases in gene size: (1) increase in the sequence of regulatory sequence; (2) presence of introns (splicing) ➢ Increases in the DNA between genes (intergenic sequences): (1) unique; (2) repeated Genes make up only a small proportion of the eukaryotic genome See Figure 7-2, 3, 4, 5; Table 7-3 3/15/05
TABLE 7-3 Contribution of Introns and Repeated Sequences to Different Genomes Table 7-3 Gene density Average number of Percentage of DNA Specles (genes/Mb) introns per gene that Is repetitive PROKARYOTES(bacteria) Escherichia co∥K-12 950 <1 EUKARYOTES (animals) Fur Saccharomyces cerevisiae 34 Invertebrates Caenorhabditis elegans 200 s96.3 Drosophila melanogaster 80 12 Vertebrates Fugu rubripes 2.7 Homo sapiens 85 46 Plants Arabidopsis thaliana 125 Oryza sativa(rice 470 nd 42
Table 7-3
Figure 7-2 Saccharomyces cerevisiae(31 genes) Drosophila melanogaster(9 genes) LII■Ⅲ Human(2 genes 2000 3000 4000 5000 6000
Figure 7-2