Genetic differentiation associated with host plants and geography among six widespread species of South American Blepharoneura fruit flies (Tephritidae).

Tropical herbivorous insects are astonishingly diverse, and many are highly host-specific. Much evidence suggests that herbivorous insect diversity is a function of host plant diversity; yet, the diversity of some lineages exceeds the diversity of plants. Although most species of herbivorous fruit flies in the Neotropical genus Blepharoneura are strongly host-specific (they deposit their eggs in a single host plant species and flower sex), some species are collected from multiple hosts or flowers and these may represent examples of lineages that are diversifying via changes in host use. Here, we investigate patterns of diversification within six geographically widespread Blepharoneura species that have been collected and reared from at least two host plant species or host plant parts. We use microsatellites to (1) test for evidence of local genetic differentiation associated with different sympatric hosts (different plant species or flower sexes) and (2) examine geographic patterns of genetic differentiation across multiple South American collection sites. In four of the six fly species, we find evidence of local genetic differences between flies collected from different hosts. All six species show evidence of geographic structure, with consistent differences between flies collected in the Guiana Shield and flies collected in Amazonia. Continent-wide analyses reveal - in all but one instance - that genetically differentiated flies collected in sympatry from different host species or different sex flowers are not one another's closest relatives, indicating that genetic differences often arise in allopatry before, or at least coincident with, the evolution of novel host use.

Cancer diagnosis with prostate specific antigen greater than 10 ng./ml. and negative peripheral zone prostate biopsy.

PURPOSE: We assessed the results of additional diagnostic procedures in men with prostate specific antigen (PSA) more than 10 ng./ml. and a peripheral zone prostate biopsy negative for cancer. MATERIALS AND METHODS: A total of 68 men with PSA more than 10 ng./ml. and a peripheral zone biopsy negative for cancer was investigated with 1 or more peripheral zone biopsies (17), prostatectomy (18), or 1 or more peripheral zone biopsies and needle biopsy of the transition zone or prostatectomy (33). RESULTS: Cancer was detected in 20 of 68 patients (29%) with 1 or more additional diagnostic procedures. Of 51 patients whose transition zone was biopsied or who underwent prostatectomy 16 had cancer, and in 8 the malignancy appeared to be isolated to the transition zone. Mean PSA density and proportion of patients with PSA density more than 0.15 were significantly greater and mean prostate volume was significantly less in the 20 patients with compared to 31 without identifiable cancer. CONCLUSIONS: At least 30% of men with PSA more than 10 ng./ml. and a negative peripheral zone biopsy have prostate cancer. In approximately 50% of cases the cancer appears to reside in the transition zone, and transition zone biopsy or prostatectomy is required for diagnosis.