Genetic mixing

The presence of TPMTk3A alleles in the African American population is consistent with the genetic mixing that has been identified through historical and molecular analysis [12, 27]. These data, compared with that of different ethnic populations, reveal that the pattern of variant TPMT alleles differs significantly be-... 

When considering the Hkely pharmacokinetic profile of a novel compound in man, it is important to recognize the variability that may be encountered in the cHnical setting. Animal pharmacokinetic studies are generally conducted in inbred animal colonies that tend to show minimal inter-subject variabiHty. The human population contains a diverse genetic mix, without the additional variability introduced by age, disease states, environmental factors and co-medications. Hence any estimate of pharmacokinetic behaviour in man must be tempered by the expected inherent variability. For compounds with high metabolic clearance (e. g. midazolam), inter-individual variability in metabolic clearance can lead to greater than 10-fold variation in oral clearance and hence systemic exposure [1]. 

Chase MW, Knapp S, Cox AV, Clarkson JJ, Butsko Y, Joseph J, Savolainen V, Parokonny AS 2003. Molecular systematics, GISH and the origin of hybrid taxa in Nicotiana (Solanaceae). Ann Bot 92 107-127 Darling KF, Wade CM, Stewart IA, Kroon D, Dingle R, Brown AJL (2000) Molecular evidence for genetic mixing of Arctic and Antarctic subpolar populations of plankton foraminifers. Nature 405 43-47 Darling KF, Kucera M, Pudsey CJ, Wade CM (2004) Molecular evidence finks cryptic diversification in polar planktonic protists to Quaternary climate dynamics. PNAS 101 7657-7662... 

Such genetic mixing is thought to occur in a susceptible animal (e.g. swine) infected with both human and avian influenza strains, resulting in a strain in which the avian surface proteins have replaced those of the human strain [7, 13,21,22],... 

Darling, K. F., Wade, C. M., Steward, I. A., Kroon, D., Dingle, R. Leigh Brown, A. J. 2000. Molecular evidence for genetic mixing of Arctic and Antarctic subpolar populations of planktonic foramin-... 

Consider these analogies. A mule is a genetic mix, a hybrid, of a horse and a donkey it is not a horse one instant and a donkey the next. Similarly, the color... 

Consider these analogies for a resonance hybrid. A mule is a genetic mix, a hybrid, of a horse and a donkey it is not a horse one instant and a donkey the next. Similarly, the color purple is a mix of two other eolors, red and blue, not red one instant and blue the next. In the same sense, a resonance hybrid is one moleeular speeies, not one resonance form this instant and another resonance form the next. The problem is that we cannot depict the hybrid accurately with a single Lewis structure. 

A potentially general method of identifying a probe is, first, to purify a protein of interest by chromatography (qv) or electrophoresis. Then a partial amino acid sequence of the protein is deterrnined chemically (see Amino acids). The amino acid sequence is used to predict likely short DNA sequences which direct the synthesis of the protein sequence. Because the genetic code uses redundant codons to direct the synthesis of some amino acids, the predicted probe is unlikely to be unique. The least redundant sequence of 25—30 nucleotides is synthesized chemically as a mixture. The mixed probe is used to screen the Hbrary and the identified clones further screened, either with another probe reverse-translated from the known amino acid sequence or by directly sequencing the clones. Whereas not all recombinant clones encode the protein of interest, reiterative screening allows identification of the correct DNA recombinant. 

The situation is somewhat more complex for virus sample amphfied or isolated directly from patient plasma, as these samples comprise a heterologous mix of related yet genetically distinct quasi-species. Often these samples contain mixtures of CCR5-tropic (R5), CXCR4-tropic (X4), and/or dual-tropic viruses these samples are classified in phenotypic ttopism assays as dual/mixed tropic (D/M) (Whitcomb etal. 2007). 

The ability to compare semiochemical patterns and to assess degrees of similarity is a likely mechanism underlying the establishment, and eventually the maintenance of genetic divergence. Amongst Tamarins (Saguinus spp.) and Marmosets, both for within- and between- (related) species distinctions, the complexity of their scent marks provides a discriminatory mechanism (Epple et ai, 1987 Smith et al., 1997). Mixed species groups of these monkeys are enabled to co-exist, to... 

Williams, P.A., Genetic interactions between mixed microbial populations, Philos. Trans. R. Soc. London, Ser. B, 297, 481-496, 1982. 

The nucleus contains bundles of a fibrous material known as chromatin, which is made up of mixed proteins and deoxyribonucleic acid (DNA), the substance that carries the genetic information of the living organism of which the cell is a component. All cells replicate by division. When a cell replicates, DNA in the chromatin of the nucleus passes the genetic information from one generation to the next one. As the cell divides, the chromatin clusters into rodlike structures known as chromo-... 

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