The Acari of fresh- and brackish water habitats in the Antarctic and sub-Antarctic regions

Neither the benthic Halacaroidea nor nektonic Hydrachnidia, characteristic of temperate and tropical freshwater mite faunas are represented among the twenty four species and sub-species of Acari recorded from the Antarctic and sub-Antarctic. The mites collected from the streams, lakes or brackish/freshwater pools of the region are either terrestrial species blown by wind into freshwater or interlopers from the marine littoral which have invaded coastal brackish pools.The present study reports on new collections of mites obtained from lakes and pools at a number of locations from both Continental and Maritime Antarctica, as well as from several sub-Antarctic islands. It reviews all published records for the region and the combined fauna is then compared with that of temperate and tropical regions.     

New murine polymorphisms detected by random amplified polymorphic DNA (RAPD) PCR and mapped by use of recombinant inbred strains

Oligonucleotide primers of random sequence that were 12 bases in length, 58% in GC content, and lacking internal palindromes were designed. By random amplified polymorphic DNA (RAPD) PCR, these primers were used to survey for DNA variations between the progenitors of the mouse AXB and BXA recombinant inbred sets (A/J and C57BL/6J). We identified 17 DNA variants detected by 10 primers. Map positions for these variants were determined by comparing their strain distribution patterns in the AXB, BXA recombinant inbred sets with strain distribution patterns of previously published loci. When necessary, BXD and NXSM recombinant inbred sets were also used. These 17 new loci mapped to 12 chromosomes. The 10 primers were also used to survey 20 inbred mouse strains including the progenitors of other recombinant inbred sets and four mouse strains recently inbred from the wild (CAST/Ei, MOLF/Ei, PERA/Ei, and SPRET/Ei).     

Molecular analysis of Saccharomyces cerevisiae chromosome I. On the number of genes and the identification of essential genes using temperature-sensitive-lethal mutations.

Previous analyses of Saccharomyces cerevisiae chromosome I have suggested that the majority (greater than 75%) of single-copy essential genes on this chromosome are difficult or impossible to identify using temperature-sensitive (Ts-) lethal mutations. To investigate whether this situation reflects intrinsic difficulties in generating temperature-sensitive proteins or constraints on mutagenesis in yeast, we subjected three cloned essential genes from chromosome I to mutagenesis in an Escherichia coli mutator strain and screened for Ts- lethal mutations in yeast using the "plasmid-shuffle" technique. We failed to obtain Ts- lethal mutations in two of the genes (FUN12 and FUN20), while the third gene yielded such mutations, but only at a low frequency. DNA sequence analysis of these mutant alleles and of the corresponding wild-type region revealed that each mutation was a single substitution not in the previously identified gene FUN19, but in the adjacent, newly identified essential gene FUN53. FUN19 itself proved to be non-essential. These results suggest that many essential proteins encoded by genes on chromosome I cannot be rendered thermolabile by single mutations. However, the results obtained with FUN53 suggest that there may also be significant constraints on mutagenesis in yeast. The 5046 base-pair interval sequenced contains the complete FUN19, FUN53 and FUN20 coding regions, as well as a portion of the adjacent non-essential FUN21 coding region. In all, 68 to 75% of this interval is open reading frame. None of the four predicted products shows significant homologies to known proteins in the available databases.     

Contagion and Alterity: Kowoj Maya Appropriations of European Objects

ABSTRACT  From initial contact with the Europeans until their conquest (C.E. 1525–1697), the Itza and their political rivals, the Kowoj, dominated Petén, Guatemala. Colonial artifacts at Zacpetén record the initial appropriations of European objects by the Kowoj. All such objects rested in ceremonial contexts, indicating that the Kowoj considered them positive sources of sacred power. The Kowoj were in contact with the Spaniards and knew they were the source of the valued materials; hence, the materials also signified otherness. Social elites frequently retained objects obtained from long distances, even those of oppressive colonial groups, as positive contagion. I argue that the Kowoj incorporated colonial objects into their rites to harness the power of alterity.     

A new cacao linkage map based on codominant markers: development and integration of 201 new microsatellite markers

A linkage map of cacao based on codominant markers has been constructed by integrating 201 new simple sequence repeats (SSR) developed in this study with a number of isoenzymes, restriction fragment length polymorphisms (RFLP), microsatellite markers and resistance and defence gene analogs (Rgenes-RFLP) previously mapped in cacao. A genomic library enriched for (GA)_n and (CA)_n was constructed, and 201 new microsatellite loci were mapped on 135 individuals from the same mapping population used to establish the first reference maps. This progeny resulted from a cross between two heterozygous cacao clones: an Upper-Amazon Forastero (UPA 402) and a Trinitario (UF 676). The new map contains 465 markers (268 SSRs, 176 RFLPs, five isoenzymes and 16 Rgenes-RFLP) arranged in ten linkage groups corresponding to the haploid chromosome number of cacao. Its length is 782.8 cM, with an average interval distance between markers of 1.7 cM. The new microsatellite markers were distributed throughout all linkage groups of the map, but their distribution was not random. The length of the map established with only SSRs was 769.6 cM, representing 94.8% of the total map. The current level of genome coverage is approximately one microsatellite every 3 cM. This new reference map provides a set of useful markers that is transferable across different mapping populations and will allow the identification and comparison of the most important regions involved in the variation of the traits of interest and the development of marker-assisted selection strategies.Communicated by H. Nybom     

Autosomal dominant macrothrombocytopenia with leukocyte inclusions (May-Hegglin anomaly) is linked to chromosome 22q12-13

Macrothrombocytopenia with leukocyte inclusions (May-Hegglin anomaly) is a rare autosomal dominant disorder characterized by thrombocytopenia, giant platelets, and D?hle body-like inclusions in leukocytes. To determine the genetic basis of this disorder, we performed a genome-wide screen for linkage in three families with May-Hegglin anomaly. For the pooled analysis of the three families, three markers on chromosome 22 had two-point logarithm-of-difference (lod) scores greater than 3, with a maximum lod score of 3.91 at a recombination fraction (theta) of 0.076 for marker D22S683. Within the largest family (MHA-1), the maximum lod score was 5.36 at theta=0 at marker D22S445. Fine mapping of recombination events using eight adjacent markers indicated that the minimal disease region of family MHA-1 alone is in the approximately 26 cM region from D22S683 to the telomere. The maximum lod score for the three families combined was 5.84 at theta=0 for marker IL2RB. With the assumption of locus homogeneity, haplotype analysis of family MHA-4 indicated the disease region is centromeric to marker D22S1045. These data best support a minimal disease region from D22S683 to D22S1045, a span of about 1 Mb of DNA that contains 17 known genes and 4 predicted genes. Further analysis of this region will identify the genetic basis of May-Hegglin anomaly, facilitating subsequent characterization of the biochemical role of the disease gene in platelet formation.