Isolation of Bacteriophage for Caryophanon latum

Bacteriophage which produce either clear or turbid center plaques have been isolated for native isolates of Caryophanon latum.     

Stable length polymorphism of up to 260 kb at the tip of the short arm of human chromosome 16

We have completed a long-range restriction map of the terminal region of the short arm of human chromosome 16 (16p13.3) by physically linking a distal genetic locus (alpha-globin) with two recently isolated probes to telomere-associated repeats (TelBam3.4 and TelBam-11). Comparison of 47 chromosomes has revealed major polymorphic length variation in this region: we have identified three alleles in which the alpha-globin genes lie 170 kb, 350 kb, or 430 kb from the telemere. The two most common alleles contain different terminal segments, starting 145 kb distal to the alpha-globin genes. Beyond this boundary these alleles are nonhomologous, yet each contains sequences related to other (different) chromosome termini. This chromosome size polymorphism has probably arisen by occasional exchanges between the subtelomeric regions of nonhomologous chromosomes; analogous length variation is likely to be present at other human telomeres.     

Detection of cryptic chromosomal abnormalities in unexplained mental retardation: a general strategy using hypervariable subtelomeric DNA polymorphisms.

Given the availability of DNA from both parents, unusual segregation of hypervariable DNA polymorphisms (HVPs) in the offspring may be attributable to deletion, unbalanced chromosomal translocation, or uniparental disomy. The telomeric regions of chromosomes are rich in both genes and hypervariable minisatellite sequences and may also be particularly prone to cryptic breakage events. Here I describe and analyze a general approach to the detection of subtelomeric abnormalities and uniparental disomy in patients with unexplained mental retardation. With 29 available polymorphic systems, approximately 50%-70% of these abnormalities could currently be detected. Development of subtelomeric HVPs physically localized with respect to their telomeres should provide a valuable resource in routine diagnostics.     

De novo truncation of chromosome 16p and healing with (TTAGGG)n in the alpha-thalassemia/mental retardation syndrome (ATR-16).

We have previously described a series of patients in whom the deletion of 1-2 megabases (Mb) of DNA from the tip of the short arm of chromosome 16 (band 16p13.3) is associated with alpha-thalassemia/mental retardation syndrome (ATR-16). We now show that one of these patients has a de novo truncation of the terminal 2 Mb of chromosome 16p and that telomeric sequence (TTAGGG)n has been added at the site of breakage. This suggests that the chromosomal break, which is paternal in origin and which probably arose at meiosis, has been stabilized in vivo by the direct addition of the telomeric sequence. Sequence comparisons of this breakpoint with that of a previously described chromosomal truncation (alpha alpha)TI do not reveal extensive sequence homology. However, both breakpoints show minimal complementarity (3-4 bp) to the proposed RNA template of human telomerase at the site at which telomere repeats have been added. Unlike previously characterized individuals with ATR-16, the clinical features of this patient appear to be solely due to monosomy for the terminal portion of 16p13.3. The identification of further patients with "pure" monosomy for the tip of chromosome 16p will be important for defining the loci contributing to the phenotype of this syndrome.     

The effect of income on the extraction of non-timber tropical forest products: Model,hypotheses, and preliminary findings from the Sumu Indians of Nicaragua

We use microeconomic theory to frame hypotheses about the effects of income on the use of non-timber rain forest products. We hypothesize that an increase in income: (a) encourages foraging specialization, resulting in the extraction of fewer goods; (b) increases the share of household income from occupations besides foraging; (c) produces a yearly value from the extraction of nontimber forest goods of about $50 per hectare; and (d) produces depletion of forest goods entering commercial channels and sustainable extraction of goods facing cheaper industrial substitutes. To examine these hypotheses we present worldwide ethnographic information and preliminary findings from field work carried out among the Sumu Indians of Nicaragua. Field work suggests that higher income produces: (a) foraging specialization with animals rather than with plants; (b) a decline in the economic importance of forest goods in household income; (c) and a rise in the value of non-timber goods removed from the forest to about $35/ha/year. We did not have time to test hypothesis d.     

Physical mapping of herpes simplex virus-induced polypeptides.

Analysis of the polypeptides induced by 29 herpes simplex virus type 1/type 2 intertypic recombinants and correlation of the data with the crossover points in the recombinant DNAs have enabled the map positions of many polypeptides to be deduced. These include 25 polypeptides which label with [35S]methionine, 11 which label with [32P]orthophosphate, and 4 which label with [14C]glucosamine. Together with the data of Preston et al. (J. Virol., in press) on the mapping of five immediate-early polypeptides, the results show that representatives of four groups of proteins--immediate-early, late, phosphorylated, and glycosylated--map in both long and short regions. The functional organization of the herpes simplex virus genome does not therefore restrict any of these four groups to either the long or the short region.     

Clinical features and molecular analysis of the α thalassemia/mental retardation syndromes. 1. Cases due to deletions involving chromosome band 16p13.3

We describe eight patients who have alpha thalassemia which cannot be accounted for by the Mendelian inheritance of abnormal alpha globin genes. Apart from the hematologic abnormality, the other universal clinical finding is mild to moderate mental handicap; there is also a broad spectrum of associated dysmorphic features. Initial analysis of the alpha globin gene complex (which maps to chromosome band 16p13.3), demonstrated that the alpha thalassemia results from failure of the patient to inherit an alpha globin allele from one of the parents. Using a combined molecular and cytogenetic approach, we have extended this analysis to show that all of these patients have 16p deletions which are variable in extent but limited to the terminal band 16p13.3; in at least four cases the deletion results from unbalanced chromosome translocation, and hence aneuploidy of a second chromosome is also present. The relatively nonspecific clinical phenotype contrasts with the other currently known microdeletion syndromes; this may reflect ascertainment bias in the recognition of such syndromes. This work represents the first step in the characterization of a new microdeletion syndrome that is probably underdiagnosed at present.