Yeast genome size

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-... 

The genome of the Helicobacterpylori bacterium is 1.6 million base pairs in size and encodes 1590 ORFs (Tomb et al., 1997). The comprehensive two-hybrid library screen performed with these ORFs differs from the yeast experiments described above in that the Gal4 activation domain library used consisted of over ten million random genomic fragments (Rain et al., 2001). Thus, the potential problem of full-size ORFs masking protein-protein interactions is reduced. A total of 261 ORFs were fused to the Gal4 DNA binding domain to create a set of baits. These ORFs... 

A main control of DNA replication occurs at the level of initiation of replication. The replication of a DNA sequence starts at specific sequence sections of the DNA, known as replication origins. In yeast, the initiation sites of DNA replication have been very well defined and characterized at the sequence level. In higher eucaryotes, in contrast, initiation has a broad initiation zone and it has not been possible to identify a defined initiation sequence. The size of the genome in eucaryotes necessitates the use of many replication origins, which can be activated in a defined time sequence and position-specific order. 

The size of the genomic DNA in eukaryotic cells (such as the cells of yeast, plants, or mammals) is much larger (up to 10+11 base pairs) than in E. coli (ca. 10+6 base pairs). The rate of the eukaryotic replication fork movement is about fifty nucleotides per second, which is about ten times slower than in E. coli. To complete replication in the relatively short time periods observed, multiple origins of replication are used. In yeast cells, these multiple origins of replication are called autonomous replication sequences (ARSs). As with prokaryotic cells, eukaryotic cells have multiple DNA polymerases. DNA polymerase S, complexed with a protein called proliferating... 

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