Genetic Diversity and Potential Function of Microbial Symbionts Associated with Newly Discovered Species of Osedax Polychaete Worms

We investigated the genetic diversity of symbiotic bacteria associated with two newly discovered species of Osedax from Monterey Canyon, CA, at 1,017-m (Osedax Monterey Bay sp. 3 "rosy" [Osedax sp. MB3]) and 381-m (Osedax Monterey Bay sp. 4 "yellow collar") depths. Quantitative PCR and clone libraries of 16S rRNA gene sequences identified differences in the compositions and abundances of bacterial phylotypes associated with the newly discovered host species and permitted comparisons between adult Osedax frankpressi and juveniles that had recently colonized whalebones implanted at 2,891 m. The newly discovered Osedax species hosted Oceanospirillales symbionts that are related to Gammaproteobacteria associated with the previously described O. frankpressi and Osedax rubiplumus (S. K. Goffredi, V. J. Orphan, G. W. Rouse, L. Jahnke, T. Embaye, K. Turk, R. Lee, and R. C. Vrijenhoek, Environ. Microbiol. 7:1369-1378, 2005). In addition, Osedax sp. MB3 hosts a diverse and abundant population of additional bacteria dominated by Epsilonproteobacteria. Ultrastructural analysis of symbiont-bearing root tissues verified the enhanced microbial diversity of Osedax sp. MB3. Root tissues from the newly described host species and O. frankpressi all exhibited collagenolytic enzyme activity, which covaried positively with the abundance of symbiont DNA and negatively with mean adult size of the host species. Members of this unusual genus of bone-eating worms may form variable associations with symbiotic bacteria that allow for the observed differences in colonization and success in whale fall environments throughout the world's oceans

A remarkable diversity of bone-eating worms (Osedax; Siboglinidae; Annelida)

<p>Abstract</p> <p>Background</p> <p>Bone-eating <it>Osedax </it>worms have proved to be surprisingly diverse and widespread. Including the initial description of this genus in 2004, five species that live at depths between 25 and 3,000 m in the eastern and western Pacific and in the north Atlantic have been named to date. Here, we provide molecular and morphological evidence for 12 additional evolutionary lineages from Monterey Bay, California. To assess their phylogenetic relationships and possible status as new undescribed species, we examined DNA sequences from two mitochondrial (<it>COI </it>and <it>16S </it>rRNA) and three nuclear genes (<it>H3</it>, <it>18S </it>and <it>28S </it>rRNA).</p> <p>Results</p> <p>Phylogenetic analyses identified 17 distinct evolutionary lineages. Levels of sequence divergence among the undescribed lineages were similar to those found among the named species. The 17 lineages clustered into five well-supported clades that also differed for a number of key morphological traits. Attempts to determine the evolutionary age of <it>Osedax </it>depended on prior assumptions about nucleotide substitution rates. According to one scenario involving a molecular clock calibrated for shallow marine invertebrates, <it>Osedax </it>split from its siboglinid relatives about 45 million years ago when archeocete cetaceans first appeared and then diversified during the late Oligocene and early Miocene when toothed and baleen whales appeared. Alternatively, the use of a slower clock calibrated for deep-sea annelids suggested that <it>Osedax </it>split from its siboglinid relatives during the Cretaceous and began to diversify during the Early Paleocene, at least 20 million years before the origin of large marine mammals.</p> <p>Conclusion</p> <p>To help resolve uncertainties about the evolutionary age of <it>Osedax</it>, we suggest that the fossilized bones from Cretaceous marine reptiles and late Oligocene cetaceans be examined for possible trace fossils left by <it>Osedax </it>roots. Regardless of the outcome, the present molecular evidence for strong phylogenetic concordance across five separate genes suggests that the undescribed <it>Osedax </it>lineages comprise evolutionarily significant units that have been separate from one another for many millions of years. These data coupled with ongoing morphological analyses provide a solid foundation for their future descriptions as new species.</p

Population structure and connectivity in Indo-Pacific deep-sea mussels of the Bathymodiolus septemdierum complex

Current pressures to mine polymetallic sulfide deposits pose threats to the animal communities found at deep-sea hydrothermal vents. Management plans aimed at preserving these unusual communities require knowledge of historical and contemporary forces that shaped the distributions and connectivity of associated species. As most vent research has focused on the eastern Pacific and mid-Atlantic ridge systems less is known about Indo-Pacific vents, where mineral extraction activities are imminent. Deep-sea mussels (Bivalvia: Mytilidae) of the genus Bathymodiolus include the morphotypic species B. septemdierum, B. brevior, B. marisindicus, and B. elongatus which are among the dominant vent taxa in western Pacific back-arc basins and the Central Indian Ridge. To assess their interpopulational relationships, we examined multilocus genotypes based on DNA sequences from four nuclear and four mitochondrial genes, and allozyme variation encoded by eleven genes. Bayesian assignment methods grouped mussels from seven widespread western Pacific localities into a single cluster, whereas the Indian Ocean mussels were clearly divergent. Thus, we designate two regional metapopulations. Notably, contemporary migration rates among all sites appeared to be low despite limited population differentiation, which highlights the necessity of obtaining realistic data on recovery times and fine-scale population structure to develop and manage conservation units effectively. Future studies using population genomic methods to address these issues in a range of species will help to inform management plans aimed at mitigating potential impacts of deep-sea mining in the Indo-Pacific region

QUARE: 1st Workshop on Measuring the Quality of Explanations in Recommender Systems

QUARE - measuring the QUality of explAnations in REcommender systems - is the first workshop that aims to promote discussion upon future research and practice directions around evaluation methodologies for explanations in recommender systems. To that end, we bring together researchers and practitioners from academia and industry to facilitate discussions about the main issues and best practices in the respective areas, identify possible synergies, and outline priorities regarding future research directions. Additionally, we want to stimulate reflections around methods to systematically and holistically assess explanation approaches, impact, and goals, at the interplay between organisational and human values. The homepage of the workshop is available at: https: //sites.google.com/view/quare-2022/

Introduction. Extent, processes and evolutionary impact of interspecific hybridization in animals

Since the time of Charles Darwin, studies of interspecific hybridization have been a major focus for evolutionary biologists. Although this phenomenon has often been viewed as problematic in the fields of ecology, taxonomy and systematics, it has become a primary source of data for studies on speciation and adaptation. Effects from genetic/evolutionary processes, such as recombination and natural selection, usually develop over extended periods of time; however, they are accelerated in cases of hybridization. Interspecific hybrids exhibit novel genomes that are exposed to natural selection, thus providing a key to unravel the ultimate causes of adaptation and speciation. Here we provide firstly a historic perspective of hybridization research, secondly a novel attempt to assess the extent of hybridization among animals and thirdly an overview of the reviews and case studies presented in this theme issue

Sympatric Australian Lasaea species (Mollusca: Bivalvia) differ in their ploidy levels, reproductive modes and developmental modes

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74949/1/j.1096-3642.1999.tb01382.x.pd

Allopatric and Sympatric Drivers of Speciation in Alviniconcha Hydrothermal Vent Snails

Despite significant advances in our understanding of speciation in the marine environment, the mechanisms underlying evolutionary diversification in deep-sea habitats remain poorly investigated. Here, we used multigene molecular clocks and population genetic inferences to examine processes that led to the emergence of the six extant lineages of Alviniconcha snails, a key taxon inhabiting deep-sea hydrothermal vents in the Indo-Pacific Ocean. We show that both allopatric divergence through historical vicariance and ecological isolation due to niche segregation contributed to speciation in this genus. The split between the two major Alviniconcha clades (separating A. boucheti and A. marisindica from A. kojimai, A. hessleri, and A. strummeri) probably resulted from tectonic processes leading to geographic separation, whereas the splits between co-occurring species might have been influenced by ecological factors, such as the availability of specific chemosynthetic symbionts. Phylogenetic origin of the sixth species, Alviniconcha adamantis, remains uncertain, although its sister position to other extant Alviniconcha lineages indicates a possible ancestral relationship. This study lays a foundation for future genomic studies aimed at deciphering the roles of local adaptation, reproductive biology, and host–symbiont compatibility in speciation of these vent-restricted snails

Simulating the Genetics Clinic of the Future - whether undergoing whole-genome sequencing shapes professional attitudes

Whole-genome sequencing (WGS) can provide valuable health insight for research participants or patients. Opportunities to be sequenced are increasing as direct-to- consumer (DTC) testing becomes more prevalent, but it is still fairly unusual to have been sequenced. We offered WGS to fourteen professionals with pre-existing familiarity with an interest in human genetics - healthcare, science, policy and art. Participants received a hard drive containing their personal sequence data files (.BAM,. gvcf), without further explanation or obligation, to consider how experiencing WGS firsthand might influence their professional attitudes. We performed semi-structured pre- and post-sequencing interviews with each participant to identify key themes that they raised after being sequenced. To evaluate how their experience of the procedure evolved over time, we also conducted a questionnaire to gather their views 3 years after receiving their genomic data. Participants were generally satisfied with the experience (all 14 participants would choose to participate again). They mostly decided to participate out of curiosity (personal) and to learn from the experience (professional). Whereas most participants slightly developed their original perspective on genetic data, a small selection of them radically changed their views over the course of the project. We conclude that personal experience of sequencing provides an interesting alternative perspective for experts involved in leading, planning, implementing or researching genome sequencing services. Moreover, the personal experience may provide professionals with a better understanding of the challenges visitors of the Genetics Clinic of the Future may face.Peer reviewe