A single generation in the wild increases fitness for descendants of hatchery-origin Chinook salmon (Oncorhynchus tshawytscha).

Reintroduction is an important tool for the recovery of imperiled species. For threatened Pacific salmonids (Oncorhynchus spp.) species, hatchery-origin (HOR) individuals from a nearby source are often used to reestablish populations in vacant, historically occupied habitat. However, this approach is challenged by the relatively low reproductive success that HOR Pacific salmonids experience when they spawn in the wild, relative to their natural-origin (NOR) counterparts. In this study, we used genetic parentage analysis to compare the reproductive success of three groups of adult Chinook salmon (Oncorhynchus tshawytscha) reintroduced above Cougar Dam on the South Fork McKenzie River, Oregon: HOR Chinook salmon from an integrated stock; first-generation, wild-born descendants (hereafter F 1s) of Chinook salmon produced at the same hatchery; and NOR Chinook salmon that are presumed to have been produced below the dam, on the mainstem McKenzie River, or elsewhere and volitionally entered a trap below Cougar Dam. We found that F 1s produced nearly as many adult offspring as NORs, and 1.8-fold more adult offspring than HORs. This result suggests that, for the South Fork McKenzie reintroduction program, a single generation in the wild increases fitness for the descendants of HOR Chinook salmon. Although these results are encouraging, care must be taken before extrapolating our results to other systems.

Antiretroviral activity and safety of once-daily etravirine in treatment-naive HIV-infected adults: 48-week results.

BACKGROUND: Etravirine (ETR), a non-nucleoside reverse transcriptase inhibitor approved for 200 mg twice-daily dosing in conjunction with other antiretrovirals (ARVs), has pharmacokinetic properties which support once-daily dosing. METHODS: In this single-arm, open-label study, 79 treatment-naive HIV-infected adults were assigned to receive ETR 400 mg plus tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) 300/200 mg once daily to assess antiviral activity, safety and tolerability. ARV activity at 48 weeks was determined by proportion of subjects with HIV-1 RNA<50 copies/ml (intention-to-treat, missing = failure). RESULTS: Of 79 eligible subjects, 90% were men, 62% African-American and 29% Caucasian. At baseline, median (Q1, Q3) age was 29 years (23, 44) and HIV-1 RNA 4.52 log10 copies/ml (4.07, 5.04). A total of 69 (87%) completed a week 48 visit and 61 (77%, 95% CI 66%, 86%) achieved HIV-1 RNA<50 copies/ml at week 48. At time of virological failure, genotypic resistance-associated mutations were detected in three participants, two with E138K (one alone and one with additional mutations). Median (95% CI) CD4(+) cell count increase was 163 (136, 203) cells/µl. Fifteen (19.0%) participants reported a new sign/symptom or lab abnormality ≥ Grade 3 and three participants (3.8%) permanently discontinued ETR due to toxicity. Two participants had psychiatric symptoms of any grade. There were no deaths. CONCLUSIONS: In this study of ARV-naive HIV-positive adults, once-daily ETR with TDF/FTC had acceptable antiviral activity and was well-tolerated. Once-daily ETR may be a plausible option as part of a combination ARV regimen for treatment-naive individuals. ClinicalTrials.gov NCT00959894.

Sequence conservation among orthologous vomeronasal type 1 receptor-like (ora) genes does not support the differential tuning hypothesis in Salmonidae.

Salmon utilize olfactory cues to guide natal stream homing during spawning migrations. Both inorganic and biogenic chemicals have been proposed as odorants that might be used by salmon during homing. In this study, we used genomic DNA sequence data from nine salmonid species to compare nucleotide identities for orthologous main olfactory receptor (mOR) genes with nucleotide identities for orthologous vomeronasal type 1-like (ora) receptor genes. We found that orthologs for both classes of olfactory receptor genes (mORs and Oras) appear to be highly conserved among species. Our findings do not support the differential tuning hypothesis in Salmonidae, which predicts higher sequence conservation for mORs than ora. We did, however, find convincing evidence for site-specific positive selection acting on paralogous main olfactory receptor genes.

Interlocus variance of F(ST) provides evidence for directional selection over an olfactory receptor gene in Coho salmon (Oncorhynchus kisutch) populations.

Coho salmon (Oncorhynchus kisutch) utilize olfactory cues to recognize and home to natal streams during spawning migrations. Chemically distinct river systems may promote directional selection for appropriately tuned olfactory receptor repertoires among Coho populations. Here, we use F(ST) outlier methods to test for a signal of selection over olfactory receptor gene-linked markers, characterized in Coho populations from four geographically proximate, but ecologically distinct rivers. We report evidence for directional selection over one such marker, OkiOR3001, and document substantially higher levels of genetic structure among Coho populations from Oregon coastal lakes than previously observed with putatively neutral microsatellites.