Primary progeny

The birth fimction for conservation of volume must be consistent with the death function because each particle death results in the birth of smaller particles, resulting from commimition. When particles of size L break, they produce a suite of daughter particles, called the primary progeny, with a size distribution p(x, L). This function applies... 

The resulting particle size distribution therefore depends to a large degree on the primary progeny function p(x, y) and to a lesser extent on the specific breakage rate. Much effort has been extended in describing the primary progeny function in a cumulative form ... 

DNA has two broad functions replication and expression. First, DNA must be able to replicate itself so that the information coded into its primary structure is transmitted faithfully to progeny cells. Second, this information must be expressed in some useful way. The method for this expression is through RNA intermediaries, which in turn act as templates for the synthesis of every protein in the body. The relationships of DNA to RNA and to protein are often expressed in a graphic syllogism called the central dogma. The concept was proposed by Crick in 1958 and was revised in 1970 to accommodate the discovery of the RNA-dependent DNA polymerase. Crick s original theory suggested that the flow of information was always from RNA to protein and could not be reversed, yet it allowed for the possibility of DNA synthesis from RNA. 

Full-length viral RNA transcripts are processed by the host machinery prior to nuclear export however, if only processed viral RNA transcripts were exported from the nucleus, viral replication would halt. Both partially spliced and fully unspliced viral RNA transcripts must be exported from the nucleus to serve as open reading frames for proteins (Gag, Pol, and Env) that are essential for completing the viral life cycle (Figures 10.1 and 10.3). Additionally, each new viral particle must contain two copies of the fully unspliced viral RNA, which serves as the primary genome for progeny virions. 

The plasmid should contain identifiable markers so that it is possible to screen progeny for the presence of the plasmid. At least two selective markers are desirable, a primary one to confirm the presence of the plasmid and a secondary marker to confirm the insertion of foreign DNA. Resistance to antibiotics is a convenient type of marker. 

FIGURE 5-2 Diagram of a chromosome-loss test for the sex chromosomes when the male is the treated parent. The regular progeny are shown as classes (a) and (b). Class (c) is a presumptive loss of either the X or Y chromosome, but a portion of such a sex chromosome lacking marker mutants may still remain. Classes (d) and (e) represent loss of the and Bs marked regions, respectively, of the Y chromosome. Class (f) is a rare class and arises from nondisjunction of the X and Y chromosome in the parental male. Classes (g) and (h) are rare classes that arise from primary nondisjunction of the X chromosomes in the parental female. Reprinted with permission from Abrahamson and Lewis.5... 

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