Background: The vertebrate clade diverged into Chondrichthyes (sharks, rays, and chimeras) and Osteichthyes fishes (bony fishes) approximately 420 mya, with each group accumulating vast anatomical and physiological differences, including skin properties. The skin of Chondrichthyes fishes is covered in dermal denticles, whereas Osteichthyes fishes are covered in scales and are mucous rich. The divergence time among these two fish groups is hypothesized to result in predictable variation among symbionts. Here, using shotgun metagenomics, we test if patterns of diversity in the skin surface microbiome across the two fish clades match predictions made by phylosymbiosis theory. We hypothesize (1) the skin microbiome will be host and clade-specific, (2) evolutionary difference in elasmobranch and teleost will correspond with a concomitant increase in host-microbiome dissimilarity, and (3) the skin structure of the two groups will affect the taxonomic and functional composition of the microbiomes. Results: We show that the taxonomic and functional composition of the microbiomes is host-specific. Teleost fish had lower average microbiome within clade similarity compared to among clade comparison, but their composition is not different among clade in a null based model. Elasmobranch's average similarity within clade was not different than across clade and not different in a null based model of comparison. In the comparison of host distance with microbiome distance, we found that the taxonomic composition of the microbiome was related to host distance for the elasmobranchs, but not the teleost fishes. In comparison, the gene function composition was not related to the host-organism distance for elasmobranchs but was negatively correlated with host distance for teleost fishes.

In general, landraces are the most diverse populations of cultivated plants (Frankel et al., 1995). Besides beingThe knowledge and understanding of the genetic structure of bean adapted to their natural and man-made environments, (Phaseolus vulgaris L.) landraces is important for the implementation of measures addressed to their management and conservation. The landrace genotypes tend to be co-adapted. Hence, gepurpose of this paper was to study the pattern of genetic variation in netic variation within a landrace may be considerable, crops (Gepts, 1993; Bretting and Widrlechner, 1995).as well as the effect of sites on uncovering adaptive traits are also discussed.

Genetic diversity of populations stored ex situ or in situ can be altered due to the management practices they are subjected to. In this paper, we compare populations of two common bean (Phaseolus vulgaris L.) landraces grown on farms with material collected from the same farms and now kept in two ex situ collections (CIAT and REGEN) with the purpose to monitor any changes that have occurred due to ex situ conservation. The diversity was measured using seven bean microsatellite markers. Further phenotypic and developmental traits were registered in a field experiment. Compared with the in situ populations, the ex situ ones had a lower level of gene diversity and we suggest that this is due to the regeneration process. Most of the phenotypic traits did not differ significantly between ex situ and in situ populations, although for yield and 100-seed weight, the CIAT material showed significant lower values. We assume that these populations have gone through an adaptational change. Overall, the conservation ex situ has been successful in maintaining the majority of the adaptations found in the landraces studied, however, the probable loss of genetic diversity that we have observed, suggest that protocols for the regeneration process must be carefully worked out if the majority of alleles are to be preserved for the future. This study also highlights the complementarity of ex situ and in situ conservation methods in order to preserve landrace adaptations and to capture new, useful diversity generated in in situ populations.

Dry matter accumulation and its partitioning to different plant components were studied in six common bean populations (two bred cultivars and four landraces) with different yield potentials. The hypothesis that yield was correlated with leaf area or mass and also with leaf area duration was tested. Leaf area and total above-ground dry matter were sampled weekly between 13 and 62 days after planting (DAP). Yield, yield components and seed yield rate were measured at the final harvest. No differences in total above-ground dry matter were observed among populations up to 62 DAP. Bred cultivars had significantly larger leaf areas than the landraces at the last harvest. Landraces initially partitioned more dry matter to reproductive organs but this was not reflected in higher yields. Temporary differences in growth rate and rate of pod formation were observed among the populations. Landraces, with one exception, tended to grow faster at early stages, and they also reached their maximum number of pods per plant earlier than the bred cultivars. Bred cultivars yielded more than all but one of the landraces. In general, yield was positively correlated with the total number of pods per plant, which in turn was well correlated with leaf area and mass. It was concluded that an increase in leaf area duration and a balanced development of reproductive organs v. other plant components are important traits in conferring improvement in yield of common bean.

2 fishes the microbiomes converge 3 Abstract 57 Background: The vertebrate clade diverged into Chondrichthyes (sharks, 58 rays, and chimeras) and Osteichthyes fishes (bony fishes) approximately 59 420 mya, with each group accumulating vast anatomical and physiological 60 differences, including skin properties. The skin of Chondrichthyes fishes is 61 covered in dermal denticles, whereas Osteichthyes fishes are covered in 62 scales and are mucous rich. The divergence time among these two fish 63groups is hypothesized to result in predictable variation among symbionts. 64Here, using shotgun metagenomics, we test if patterns of diversity in the 65 skin surface microbiome across the two fish clades match predictions made 66 by phylosymbiosis theory. We hypothesize, 1) the skin microbiome will be 67 species and clade-specific, 2) evolutionary difference in elasmobranch and 68 teleost fishes corresponds with a concomitant increase in host-microbiome 69 dissimilarity and 3) the skin structure of the two groups will affect the 70 taxonomic and functional composition of the microbiomes. 71Results: We show that the taxonomic and functional composition of the 72 microbiomes is host species-specific. Teleost fish had lower average 73 microbiome within clade similarity compared to among clade comparison, 74 but their composition is not different among clade in a null based model. 75Elasmobranch's average similarity within clade was not different than 76 across clade and not different in a null based model of comparison. In the 77 comparison of host distance with microbiome distance, we found that the 78 taxonomic composition of the microbiome was related to host distance for 79 the elasmobranchs, but not the teleost fishes. In comparison, the gene 80 function composition was not related to the host-organism distance for 81 elasmobranchs but was negatively correlated with host distance for teleost 82 fishes. 83 Conclusion: Our results show the patterns of phylosymbiosis are not 84 consistent across both fish clades, with the elasmobranchs showing 85 phylosymbiosis, while the teleost fish are not. The discrepancy may be 86 linked to alternative processes underpinning microbiome assemblage, 87 including possible historical host-microbiome evolution of the 88 elasmobranchs and convergent evolution in the teleost which filter specific 89 microbial groups. Our comparison of the microbiomes among fishes 90 represents an investigation into the microbial relationships of the oldest 91 divergence extant vertebrate host and reveals that microbial relationships 92 are not consistent across evolutionary timescales.93