Understanding the relative fitness of naturally spawning hatchery fish compared with wild fish has become an important issue in the management and conservation of salmonids. We used a DNA-based parentage analysis to measure the relative reproductive success of hatchery- and natural-origin spring Chinook salmon ( Oncorhynchus tshawytscha ) in the natural environment. Size and age had a large influence on male fitness, with larger and older males producing more offspring than smaller or younger individuals. Size had a significant effect on female fitness, but the effect was smaller than on male fitness. For both sexes, run time had a smaller but still significant effect on fitness, with earlier returning fish favored. Spawning location within the river had a significant effect on fitness for both sexes. Hatchery-origin fish produced about half the juvenile progeny per parent when spawning naturally than did natural-origin fish. Hatchery fish tended to be younger and return to lower areas of the watershed than wild fish, which explained some of their lower fitness.

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We assessed the population genetic structure and temporal stability of genetic diversity from 1999 to 2001 in collections of fall-run Chinook salmon Oncorhynchus tshawytscha in California's Central Valley. Tests for genotypic differentiation at seven microsatellite loci revealed few significant pairwise comparisons between samples from five hatchery populations and eight naturally spawning populations throughout the Central Valley that were separated by 50-350 km. All collections were genetically homogeneous and failed to cluster with their nearest geographic neighbors. Likewise, evaluation of temporal change in genetic diversity revealed few changes over the 3 years of the study. Our results suggest that fall-run Chinook salmon throughout the Central Valley comprise a genetically homogeneous population that has lower among-population genetic diversity than fall-run Chinook salmon populations examined elsewhere over similar geographic scales. The lack of genetic distinction and the lack of temporal differences in allele frequencies between hatchery and naturally spawning fish indicate that considerable gene flow occurs between fall-run Chinook salmon throughout the Central Valley. Due to the prevalence of off-site release of hatchery-reared juveniles and the history of interbasin hatchery transfers and stocking within the Central Valley, homogenization of Central Valley fall-run populations is most likely the result of hatchery practices for the past 140 years.

There is significant debate regarding whether B cells and their antibodies contribute to effective anti-cancer immune responses. Here we show that patients with metastatic but non-progressing melanoma, lung adenocarcinoma, or renal cell carcinoma exhibited increased levels of blood plasmablasts. We used a cell-barcoding technology to sequence their plasmablast antibody repertoires, revealing clonal families of affinity matured B cells that exhibit progressive class switching and persistence over time. Anti-CTLA4 and other treatments were associated with further increases in somatic hypermutation and clonal family size. Recombinant antibodies from clonal families bound non-autologous tumor tissue and cell lines, and families possessing immunoglobulin paratope sequence motifs shared across patients exhibited increased rates of binding. We identified antibodies that caused regression of, and durable immunity toward, heterologous syngeneic tumors in mice. Our findings demonstrate convergent functional anti-tumor antibody responses targeting public tumor antigens, and provide an approach to identify antibodies with diagnostic or therapeutic utility.