Genome units

Ricardo Ramos, Genomic Unit, Scientific Park of Madrid, Madrid, Spain... 

Gene Expression and Genomics Unit Tried Technology Center, Room 207 333 Cassell Drive Baltimore. MD 21224-6825... 

Figure 2,6. A schematic representation of the organization of a mitochondrial genome unit of yeast. Grey stretches represent genes, white stretches AT spacers, black bars GC clusters. (From Bernardi, 1979a).

The next step was the precise definition of the sequences involved in the excision process. The basic idea of the deletion model mentioned above was that the instability of the mitochondrial genome of yeast was due to the existence in each genome unit of a number of nucleotide sequences having enough homology to allow illegitimate, unequal recombination to take place. In this respect, clearly the GC clusters were at least as good candidates as the AT spacers. 

To summarize, the first event in the spontaneous cytoplasmic petite mutation is the excision of a segment from one of the 25-50 mitochondrial genome units (Fig. 2.9) of a... 

Figure 2.9. Physical and genetical map of the mitochondrial genome unit of wild-type yeast (strain A). Some restriction sites are indicated. Circled numbers indicate the location of ori sequences 1-8 (arrowheads point in the direction cluster C to cluster A sec Fig. 2.8). Black and dotted areas correspond to exons and introns of mitochondrial genes, respectively. Thin radial lines ending in small circles indicate tRNA genes. White areas correspond to long AT spacers embedding short GC clusters. (Modified from de Zamaroezy et al.,...

Chromosome Discrete unit of the genome consisting of a single molecule of DNA that carrit many genes. 

Chromosomes are extremely complex chemicals that are assembled from simple repeating units and contain all the chemical information needed to reproduce animate species. Each living organism has its own complete set of chromosomes, called the genome. 

The genome, through its constituent DNAs, provides all of the codes needed for building a wide range of peptides, proteins, and enzymes, which in turn utilize raw materials (food) to form an animate body and keep it going. These multiple reactions work together as a unit within a water-filled cell. 

Short (2-6 bp), inherited, tandem repeat units of DNA occur about 50,000-100,000 times in the human genome (Chapter 36). Because they occur more frequently—and in view of the routine application of sensitive PCR methods—they are replacing RFLPs as the marker loci for various genome searches. 

Human Genome Project Information http //www.ornl.gov/hgmis/ (From the Human Genome Program of the United States Department of Energy.)... 

United States Department of Energy Joint Genome Institute Walnut Creek, California... 

Sankoff, D., Leduc, G., Antoine, N. et al. (1992) Gene order comparisons for phylogenetic inference evolution of the mitochondrial genome. Proceedings of the National Academy of Sciences of the United States of America, 89 (14), 6575-6579. 

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