Species-specific genes

Potentially, interferon is an ideal anhviral agent in that it acts on many different vimses and is not toxic to host cells. However, the exploitation of this agent in the treatment of viral infechons has been delayed by a number of factors. For example, it has proved to be species-specific and interferons raised in animal sources offered little protechon to human cells. Human interferon is thus needed for the treatment of human infechons and the produehon and purificahon of human interferon on a large scale has proved difficult. The inserhon of human genes for interferon into E. coli has resolved the produehon problems (Chapter 24). Clinical trials have demonstrated that interferon prevents rhinovirus infeehon and has a beneficial effect in herpes, cytomegalovims and hepahtis B vims infechons. 

A. Bubert, S. Kohler, and W. Goebel, The homologus and heterologous regions within the lAP-gene and genus-specific and species-specific identification of Listeria by polymera.se chain-reaction. Appl. Environ. Microbiol.. 5S 2632 (1992). 

Figure 19 Sample gel of the results of a PCR. Lane 1 is a 100-bp molecular marker lanes 2-6 are samples. The presence of the top bands (the species-specific endogenous gene) demonstrates that the PCR amplification was successfiil. Lack of the middle band (the introduced effect gene) and the bottom band (the selectable marker gene) in lane 3 indicates that sample is negative for the effect gene. Presence of all three bands in the remaining lanes indicates the samples are positive for the effect gene...

These reference genes demonstrate that the DNA isolated was of sufficient quality and quantity for PCR amplification. It is assumed that in the course of food processing, the species-specific reference gene and the transgene are degraded in a similar manner. It is also assumed that effects of the matrix on PCR amplification will be similar. The reduced amplification efficiency of both genes presumably has no effect on the ratio of their amounts, which reflects the ratio of modified and unmodified DNA. 

QUATTROCCHIO, F, WING, J.F., VAN DER WOUDE, K., MOL, J.N.M., KOES, R., Analysis of bHLH and MYB domain proteins Species-specific regulatory differences are caused by divergent evolution of target anthocyanin genes, Plant J., 1998,13,475-488. 

With a morphine biosynthetic gene in hand, we believed we could begin to address the question why only P. somniferum produces morphine, while other Papaver species such as P. rhoeas, P. orientale, and P. bracteatum do not. Unexpectedly, we found that the codeinone reductase transcript was present to some degree in all four species investigated. A review of the literature revealed no alkaloids reported in P. rhoeas for which codeinone reductase should participate in the synthesis. Similarly, P. orientale accumulates the alternate morphine biosynthetic precursor oripavine, but codeinone reductase is not involved in the biosynthesis of oripavine, acting instead after this alkaloid along the biosynthetic pathway to morphine.22 P. bracteatum produces the morphine precursor thebaine as a major alkaloid. As for oripavine in P. orientale, codeinone reductase would act in P. bracteatum after thebaine formation on the pathway to morphine. It appears, therefore, that the reason that P. rhoeas, P. orientale, and P. bracteatum do not produce morphine is not related to the absence of the transcript of the morphine biosynthesis-specific gene codeinone reductase. The expression of codeinone reductase may simply be an evolutionary remnant in these species. 

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