Optical mapping of BAC clones from the human Y chromosome DAZ locus.

The accurate mapping of clones derived from genomic regions containing complex arrangements of repeated elements presents special problems for DNA sequencers. Recent advances in the automation of optical mapping have enabled us to map a set of 16 BAC clones derived from the DAZ locus of the human Y chromosome long arm, a locus in which the entire DAZ gene as well as subsections within the gene copies have been duplicated. High-resolution optical mapping employing seven enzymes places these clones into two contigs representing four distinct copies of the DAZ gene and highlights a number of differences between individual copies of DAZ.

In vitro aggregation facilities beta-amyloid peptide-(25-35)-induced amnesia in the rat.

The beta-amyloid peptide-(25-35) fragment, but not beta-amyloid peptide-(1-28), shares with beta-amyloid protein-(1-42) the ability to self-aggregate and to induce neurotoxicity in vitro. This study examined the induction of amnesia in rats given intracerebroventricularly soluble or aggregated beta-amyloid peptide-(25-35) (5-45 nmol), or beta-amyloid peptide-(1-28) (15 nmol). Memory deficit in the water-maze test, examined 14 days after aggregated beta-amyloid peptide-(25-35) injection, was more pronounced than with soluble beta-amyloid peptide-(25-35).