Nuclear Pseudogenes

Segments of the mtGenome are present in the human nuclear genome (Collura and Stewart 1995, Zischler et al. 1995, Wallace et al. 1997). These 'molecular fossils' or pseudogenes are rare events caused by migration and integration of a portion of the mtGenome into nuclear DNA. Zischler et al. (1995) reported that human chromosome 11 carries a portion of the mtDNA control region that reflects an ancient genetic transposition from the mitochondrion to the nuclear genome. This element differs from typical modern mtDNA sequences by approximately 7.5% and has not created problems with regular forensic casework (Morgan et al. 1998).

These nuclear fossils of the mtGenome can create the potential for complications in mtDNA human identity testing if they are amplified instead of the intended mtDNA target when a high number of PCR cycles are invoked to try and tease out mtDNA sequence information from a particularly difficult sample (Morgan et al. 1998). Under unique circumstances, nuclear pseudogenes could act to contaminate the true mtDNA sequence. Such was likely the case with the high degree of heteroplasmy reported on some hair samples that are amplified with a nested PCR approach involving a cumulative number of 60 cycles (Grzybowski 2000, Budowle et al. 2002a, Brandst├Ątter and Parson 2003). However, with primer sets commonly used in forensic mtDNA testing and a direct PCR with fewer than 40 cycles, nuclear DNA sequences that are similar to mtDNA rarely cause a problem because their initial copy number is so much lower than that of mtDNA.

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Stammering Its Cause and Its Cure

Stammering Its Cause and Its Cure

This book discusses the futility of curing stammering by common means. It traces various attempts at curing stammering in the past and how wasteful these attempt were, until he discovered a simple program to cure it. The book presents the life of Benjamin Nathaniel Bogue and his struggles with the handicap. Bogue devotes a great deal of text to explain the handicap of stammering, its effects on the body and psychology of the sufferer, and its cure.

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