Germ-line DNA

Most oncogenic mutations occur in somatic cells and are not carried in the germ-line DNA. 

Even without a diversity-generating system, higher invertebrates "will have a rather large number of variable sequences in the germ-line DNA. These will allow for an immune response although -without the power and flexibility of the vertebrate system. Some invertebrates live for many years, but most have a fairly short life-span, which probably diminishes the importance of the immune system somewhat. 

Information metabolism provides a way to store and retrieve the information that guides the development of cellular structure, communication, and regulation. Like other metabolic pathways, this process is highly regulated. Information is stored by the process of DNA replication and meiosis, in which we form our germ-line cells. These processes are limited to specific portions of the cell cycle. Information is retrieved by the transcription of DNA into RNA and the ultimate translation of the signals in the mRNA into protein. 

De Smet C, Lurquin C, Lethe B, Martelange V, Boon T (1999) DNA methylation is the primary silencing mechanism for a set of germ line- and mmor-specific genes with a CpG-rich promoter. Mol Cell Biol 19 7327-7335... 

The first method described was the direct microinjection of the vector DNA with only minor alterations in the target gene into ES cells (Zimmer and Gruss, 1989). Because of the high transfection frequency observed with this method (20%), it was not necessary to use a selection marker. However, this method is technically very difficult to perform and no laboratory could successfully reproduce this procedure, nor have these cells been reported to be transmitted through the germ-line. 

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