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Iron is an essential nutrient required for the function of all cells, most notably for the production of hemoglobin in red blood cells. Defects in the mechanisms of iron absorption, storage, or utilization can lead to disorders of iron-limited erythropoiesis or iron overload. In an effort to further understand these processes, we have used the zebrafish as a genetic system to study vertebrate iron metabolism. Here we characterized the phenotype ofchardonnay(cdy), a zebrafish mutant with hypochromic, microcytic anemia, and positioned the mutant gene on linkage group 11. The cdygene was isolated by a functional genomics approach in which we used a combination of expression studies, sequence analyses, and radiation hybrid panel mapping. We identified erythroid-specific genes using a whole embryo mRNA in situ hybridization screen and placed these genes on the zebrafish genomic map. One of these genes encoded the iron transporter divalent metal transporter 1 (DMT1) and colocalized with the cdygene. We identified a nonsense mutation in the cdyallele and demonstrated that, whereas wild-type zebrafish DMT1 protein can transport iron, the truncated protein expressed in cdymutants is not functional. Our studies further demonstrate the conservation of iron metabolism in vertebrates and suggest the existence of an alternative pathway of intestinal and red blood cell iron uptake.

Iron is an essential nutrient required for the function of all cells, most notably for the production of hemoglobin in red blood cells. Defects in the mechanisms of iron absorption, storage, or utilization can lead to disorders of iron-limited erythropoiesis or iron overload. In an effort to further understand these processes, we have used the zebrafish as a genetic system to study vertebrate iron metabolism. Here we characterized the phenotype ofchardonnay (cdy), a zebrafish mutant with hypochromic, microcytic anemia, and positioned the mutant gene on linkage group 11. The cdy gene was isolated by a functional genomics approach in which we used a combination of expression studies, sequence analyses, and radiation hybrid panel mapping. We identified erythroid-specific genes using a whole embryo mRNA in situ hybridization screen and placed these genes on the zebrafish genomic map. One of these genes encoded the iron transporter divalent metal transporter 1 (DMT1) and colocalized with the cdy gene. We identified a nonsense mutation in the cdy allele and demonstrated that, whereas wild-type zebrafish DMT1 protein can transport iron, the truncated protein expressed in cdymutants is not functional. Our studies further demonstrate the conservation of iron metabolism in vertebrates and suggest the existence of an alternative pathway of intestinal and red blood cell iron uptake.

Examines exhibitions `Indigena: Contemporary Native Perspectives' at the Canadian Museum of Civilization and `Land, Spirit, Power: First Nations at the National Gallery of Canada'. Inversion of conventional practices of ethnographic museums and art galleries; Similarities and contrasts.

Q banding of chromosome preparations from lake trout revealed the presence of heteromorphic quinacrine bright bands on several chromosomes. All of the metacentric chromosome pairs can be distinguished on the basis of number, position and intensity of the quinacrine bright bands and chromosome size. These bands appear to represent heterochromatin, since they are darkly staining with the C band technique. Since all of the fish examined had consistent heteromorphisms at several of the quinacrine bright bands, these chromosome markers should be useful in genetic comparisons between different trout stocks and populations.

The chromosomes of lake trout (Salvelinus namaycush) contain a considerable amount of heterochromatin located at the centromeres and/or telomeres of several chromosomes, including a sex-specific block located distally on the X chromosome. In order to investigate further the repetitive DNAs of lake trout, genomic DNA from a female was size fractionated (<600 bp) with the restriction endonuclease AluI and fragments were cloned into the bacteriophage M13. A total of 42 clones were isolated. Relative copy number of individual inserts within the lake trout genome was estimated by Southern analysis. Twelve clones were determined to be highly repetitive and were chosen for further investigation. Inserts of these clones contained sequences similar to the AluI/RsaI, EcoRI/DraI, DraI/BstEII, and MboI/BglII families reported from Arctic char (Salvelinus alpinus). The chromosomal location of several of these fragments was determined in lake trout by fluorescence in situ hybridization (FISH). Two related AluI/RsaI sequences (Type A, ~ 140 bp, and Type B, ~ 120 bp) showed differential hybridization. Type A hybridized to the centromeres of all metacentric as well as several acrocentric chromosomes. Type B hybridized to the centromeres of most acrocentric chromosomes. A sequence with homology to the EcoRI/DraI family hybridized to the centromeres of several acrocentric chromosomes. Sequences with partial similarity to the DraI/BstEII family hybridized to the major rDNA sites (nucleolar organizer regions, NORs) and several minor telomeric sites. The interstitial and telomeric heterochromatin of lake trout, including that of the X chromosome, appears to comprise sequences belonging to the MboI/BglII family.

Abstract.: This study was designed to characterize further the nontranscribed intergenic spacers (NTSs) of the 5S rRNA genes of fish and evaluate this marker as a tool for comparative studies. Two members of the closely related North American Great Lakes cisco species complex (Coregonus artedi and C. zenithicus) were chosen for comparison. Fluorescence in situ hybridization found the ciscoes to have a single multicopy 5S locus located in a C band-positive region of the largest submetacentric chromosome. The entire NTS was amplified from the two species by polymerase chain reaction with oligonucleotide primers anchored in the conserved 5S coding region. Complete sequences were determined for 25 clones from four individuals representing two discrete NTS length variants. Sequence analysis found the length variants to result from presence of a 130-bp direct repeat. No two sequences from a single fish were identical. Examination of sequence from the coding region revealed two types of 5S genes in addition to pseudogenes. This suggests the presence of both somatic and germline (oocyte) forms of the 5S gene in the genome of Coregonus. The amount of variation present among NTS sequences indicates that accumulation of variation (mutation) is greater in this multicopy gene than is gene conversion (homogenization). The high level of sequence variation makes the 5S NTS an inappropriate DNA sequence for comparisons of closely related taxa.

The article discusses the miniaturization of objects in North America. It highlights the dolls and other miniature objects such as model canoes, wigwams, tomahawks and other arts. It further highlights the relationship of souvenir miniatures to other kinds of miniature objects made by native people and to identify the common iconographic themes as they appear in both two and three dimensional art.