Dataset Information

DNA variation and symbiotic associations in phenotypically diverse sea urchin Strongylocentrotus intermedius.

ABSTRACT: Strongylocentrotus intermedius (A. Agassiz, 1863) is an economically important sea urchin inhabiting the northwest Pacific region of Asia. The northern Primorye (Sea of Japan) populations of S. intermedius consist of two sympatric morphological forms, "usual" (U) and "gray" (G). The two forms are significantly different in morphology and preferred bathymetric distribution, the G form prevailing in deeper-water settlements. We have analyzed the genetic composition of the S. intermedius forms using the nucleotide sequences of the mitochondrial gene encoding the cytochrome c oxidase subunit I and the nuclear gene encoding bindin to evaluate the possibility of cryptic species within S. intermedius. We have examined the presence of symbiont microorganisms by means of 16S rRNA sequences. The nucleotide sequence divergence between the morphological forms is low: 0.74% and 0.70% for cytochrome c oxidase subunit I and nuclear gene encoding bindin, respectively, which is significantly below average intrageneric sequence divergence among Strongylocentrotus species. We thus have found no genetic evidence of cryptic species within S. intermedius. Phylogenetic analysis shows that the bacteria symbionts of S. intermedius belong to the phylum Bacteroidetes, but the U and G forms predominantly harbor highly divergent bacterial lineages belonging to two different taxonomic classes, Flavobacteria and Sphingobacteria. We propose that the U and G forms of S. intermedius represent distinct ecomorphological adaptations to contrasting shallow- and deep-water marine environments and might be considered incipient species. We also propose that the symbiotic bacteria likely play an important role in the evolution of morphological divergence of S. intermedius.

SUBMITTER: Balakirev ES

PROVIDER: S-EPMC2571021 | biostudies-literature | 2008 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

DNA variation and symbiotic associations in phenotypically diverse sea urchin Strongylocentrotus intermedius.

Balakirev Evgeniy S ES Pavlyuchkov Vladimir A VA Ayala Francisco J FJ

Proceedings of the National Academy of Sciences of the United States of America 20081013 42

Strongylocentrotus intermedius (A. Agassiz, 1863) is an economically important sea urchin inhabiting the northwest Pacific region of Asia. The northern Primorye (Sea of Japan) populations of S. intermedius consist of two sympatric morphological forms, "usual" (U) and "gray" (G). The two forms are significantly different in morphology and preferred bathymetric distribution, the G form prevailing in deeper-water settlements. We have analyzed the genetic composition of the S. intermedius forms usin ...[more]

PMID: 18852450

Similar Datasets

Project description:Small sea urchins Strongylocentrotus intermedius (1-2 cm of test diameter) are exposed to different environments of light intensities after being reseeded to the sea bottom. With little information available about the behavioral responses of S. intermedius to different light intensities in the environment, we carried out an investigation on how S. intermedius is affected by three light intensity environments in terms of phototaxis, foraging and righting behaviors. They were no light (zero lx), low light intensity (24-209 lx) and high light intensity (252-2,280 lx). Light intensity had obvious different effects on phototaxis. In low light intensity, sea urchins moved more and spent significantly more time at the higher intensity (69-209 lx) (P = 0.046). S. intermedius in high light intensity, in contrast, spent significantly more time at lower intensity (252-690 lx) (P = 0.005). Unexpectedly, no significant difference of movement (average velocity and total distance covered) was found among the three light intensities (P > 0.05). Foraging behavior of S. intermedius was significantly different among the light intensities. In the no light environment, only three of ten S. intermedius found food within 7 min. In low light intensity, nine of 10 sea urchins showed successful foraging behavior to the food placed at 209 lx, which was significantly higher than the ratio of the number (two of 10) when food was placed at 24 lx (P = 0.005). In the high light intensity, in contrast, significantly less sea urchins (three of 10) found food placed at the higher light intensity (2,280 lx) compared with the lower light intensity (252 lx) (10/10, P = 0.003). Furthermore, S. intermedius showed significantly longer righting response time in the high light intensity compared with both no light (P = 0.001) and low light intensity (P = 0.031). No significant difference was found in righting behavior between no light and low light intensity (P = 0.892). The present study indicates that light intensity significantly affects phototaxis, foraging and righting behaviors of S. intermedius and that ~200 lx might be the appropriate light intensity for reseeding small S. intermedius.

Project description:Ocean warming increasingly endangers the fitness of marine invertebrates. Transgenerational effects (TE) potentially mitigate the impacts of environmental stress on the embryos of marine invertebrates. The molecular mechanisms, however, remain largely unknown. Using high-throughput RNA sequencing technology, we investigated the gene expression patterns of embryos (the gastrula stage) of the sea urchin Strongylocentrotus intermedius at different developmental temperatures, whose parents were exposed to long-term (15 months) elevated temperature (A) or not (B). The temperatures at which adults were held for ~4 weeks prior to the start of the experiment (21?°C for A and 18?°C for B) were also used for the development of offspring (high: 21?°C and ambient (laboratory): 18?°C) resulting in four experimental groups (HA and HB at 21?°C, and LA and LB at 18?°C). The embryos were sampled ~24?h after fertilization. All samples were in the gastrula stage. Twelve mRNA libraries (groups HA, HB, LA, LB, 3 replicates for each group) were established for the following sequencing. Embryos whose parents were exposed to elevated temperatures or not showed 1891 significantly different DEGs (differentially expressed genes) at the ambient developmental temperature (LB vs LA, LB as control) and 2203 significantly different DEGs at the high developmental temperature (HB vs HA, HB as control), respectively. This result indicates complex molecular mechanisms of transgenerational effects of ocean warming, in which a large number of genes are involved. With the TE, we found 904 shared DEGs in both LB vs LA (LB as control) and HB vs HA (HB as control) changed in the same direction of expression (i.e., up- or down-regulated), indicating that parental exposed temperatures affect the expression of these genes in the same manner regardless of the development temperature. With developmental exposure, we found 198 shared DEGs in both HB vs LB (HB as control) and HA vs LA (HA as control) changed in the same direction of expression. Of the 198 DEGs, more genes were up-regulated at high developmental temperature. Interestingly, embryos whose parents were exposed to high temperature showed fewer differently expressed DEGs between high and low developmental temperatures than the individuals whose parents were exposed to ambient temperature. The results indicate that gene expressions are probably depressed by the transgenerational effect of ocean warming. The roles of hsp70 and hnf6 in thermal acclimation are highlighted for future studies. The present study provides new insights into the molecular mechanisms of the transgenerational and developmental effects of ocean warming on the embryos of sea urchins.

Dataset Information

DNA variation and symbiotic associations in phenotypically diverse sea urchin Strongylocentrotus intermedius.

Publications

DNA variation and symbiotic associations in phenotypically diverse sea urchin Strongylocentrotus intermedius.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets