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101.
Jennifer A. Jackson Debbie J. Steel P. Beerli Bradley C. Congdon Carlos Olavarría Matthew S. Leslie Cristina Pomilla Howard Rosenbaum C. Scott Baker 《Proceedings. Biological sciences / The Royal Society》2014,281(1786)
Humpback whales (Megaptera novaeangliae) annually undertake the longest migrations between seasonal feeding and breeding grounds of any mammal. Despite this dispersal potential, discontinuous seasonal distributions and migratory patterns suggest that humpbacks form discrete regional populations within each ocean. To better understand the worldwide population history of humpbacks, and the interplay of this species with the oceanic environment through geological time, we assembled mitochondrial DNA control region sequences representing approximately 2700 individuals (465 bp, 219 haplotypes) and eight nuclear intronic sequences representing approximately 70 individuals (3700 bp, 140 alleles) from the North Pacific, North Atlantic and Southern Hemisphere. Bayesian divergence time reconstructions date the origin of humpback mtDNA lineages to the Pleistocene (880 ka, 95% posterior intervals 550–1320 ka) and estimate radiation of current Northern Hemisphere lineages between 50 and 200 ka, indicating colonization of the northern oceans prior to the Last Glacial Maximum. Coalescent analyses reveal restricted gene flow between ocean basins, with long-term migration rates (individual migrants per generation) of less than 3.3 for mtDNA and less than 2 for nuclear genomic DNA. Genetic evidence suggests that humpbacks in the North Pacific, North Atlantic and Southern Hemisphere are on independent evolutionary trajectories, supporting taxonomic revision of M. novaeangliae to three subspecies. 相似文献
102.
103.
Ana R. Amaral Gretchen Lovewell Maria M. Coelho George Amato Howard C. Rosenbaum 《PloS one》2014,9(1)
Natural hybridization may result in the exchange of genetic material between divergent lineages and even the formation of new taxa. Many of the Neo-Darwinian architects argued that, particularly for animal clades, natural hybridization was maladaptive. Recent evidence, however, has falsified this hypothesis, instead indicating that this process may lead to increased biodiversity through the formation of new species. Although such cases of hybrid speciation have been described in plants, fish and insects, they are considered exceptionally rare in mammals. Here we present evidence for a marine mammal, Stenella clymene, arising through natural hybridization. We found phylogenetic discordance between mitochondrial and nuclear markers, which, coupled with a pattern of transgressive segregation seen in the morphometric variation of some characters, support a case of hybrid speciation. S. clymene is currently genetically differentiated from its putative parental species, Stenella coerueloalba and Stenella longisrostris, although low levels of introgressive hybridization may be occurring. Although non-reticulate forms of evolution, such as incomplete lineage sorting, could explain our genetic results, we consider that the genetic and morphological evidence taken together argue more convincingly towards a case of hybrid speciation. We anticipate that our study will bring attention to this important aspect of reticulate evolution in non-model mammal species. The study of speciation through hybridization is an excellent opportunity to understand the mechanisms leading to speciation in the context of gene flow. 相似文献
104.
Qing Li Steven R. Eichten Peter J. Hermanson Virginia M. Zaunbrecher Jawon Song Jennifer Wendt Heidi Rosenbaum Thelma F. Madzima Amy E. Sloan Ji Huang Daniel L. Burgess Todd A. Richmond Karen M. McGinnis Robert B. Meeley Olga N. Danilevskaya Matthew W. Vaughn Shawn M. Kaeppler Jeffrey A. Jeddeloh Nathan M. Springer 《The Plant cell》2014,26(12):4602-4616
DNA methylation can play important roles in the regulation of transposable elements and genes. A collection of mutant alleles for 11 maize (Zea mays) genes predicted to play roles in controlling DNA methylation were isolated through forward- or reverse-genetic approaches. Low-coverage whole-genome bisulfite sequencing and high-coverage sequence-capture bisulfite sequencing were applied to mutant lines to determine context- and locus-specific effects of these mutations on DNA methylation profiles. Plants containing mutant alleles for components of the RNA-directed DNA methylation pathway exhibit loss of CHH methylation at many loci as well as CG and CHG methylation at a small number of loci. Plants containing loss-of-function alleles for chromomethylase (CMT) genes exhibit strong genome-wide reductions in CHG methylation and some locus-specific loss of CHH methylation. In an attempt to identify stocks with stronger reductions in DNA methylation levels than provided by single gene mutations, we performed crosses to create double mutants for the maize CMT3 orthologs, Zmet2 and Zmet5, and for the maize DDM1 orthologs, Chr101 and Chr106. While loss-of-function alleles are viable as single gene mutants, the double mutants were not recovered, suggesting that severe perturbations of the maize methylome may have stronger deleterious phenotypic effects than in Arabidopsis thaliana. 相似文献
105.
Marcy Rosenbaum 《Medical anthropology quarterly》2000,14(4):630-632
Preventing and Controlling Cancer in North America:. Cross-Cultural Perspective. Diane Weiner. ed. Westport, CT: Praeger Publishers, 1999. xvii. 245 pp.
Evaluating Alternative Cancer Therapies:. Guide to the Science and Politics of an Emerging Medical Field. David J. Hess. New Brunswick, NJ: Rutgers University Press, 1999. xxi. 260 pp. 相似文献
Evaluating Alternative Cancer Therapies:. Guide to the Science and Politics of an Emerging Medical Field. David J. Hess. New Brunswick, NJ: Rutgers University Press, 1999. xxi. 260 pp. 相似文献
106.
The results described in the accompanying article support the model in
which glucosylphosphoryldolichol (Glc-P-Dol) is synthesized on the
cytoplasmic face of the ER, and functions as a glucosyl donor for three
Glc-P-Dol:Glc0-2Man9-GlcNAc2-P-P-Dol glucosyltransferases (GlcTases) in the
lumenal compartment. In this study, the enzymatic synthesis and structural
characterization by NMR and electrospray-ionization tandem mass
spectrometry of a series of water-soluble beta-Glc-P-Dol analogs containing
2-4 isoprene units with either the cis - or trans - stereoconfiguration in
the beta-position are described. The water- soluble analogs were (1) used
to examine the stereospecificity of the Glc-P-Dol:Glc0-2Man9GlcNAc2-P-P-Dol
glucosyltransferases (GlcTases) and (2) tested as potential substrates for
a membrane protein(s) mediating the transbilayer movement of Glc-P-Dol in
sealed ER vesicles from rat liver and pig brain. The Glc-P-Dol-mediated
GlcTases in pig brain microsomes utilized [3H]Glc-labeled Glc-P-Dol10,
Glc-P-(omega, c )Dol15, Glc-P(omega, t,t )Dol20, and Glc-P-(omega, t,c
)Dol20as glucosyl donors with [3H]Glc3Man9GlcNAc2-P-P-Dol the major product
labeled in vitro. A preference was exhibited for C15-20 substrates
containing an internal cis -isoprene unit in the beta-position. In
addition, the water-soluble analog, Glc-P-Dol10, was shown to enter the
lumenal compartment of sealed microsomal vesicles from rat liver and pig
brain via a protein-mediated transport system enriched in the ER. The
properties of the ER transport system have been characterized. Glc-
P-Dol10was not transported into or adsorbed by synthetic PC-liposomes or
bovine erythrocytes. The results of these studies indicate that (1) the
internal cis -isoprene units are important for the utilization of Glc-P-Dol
as a glucosyl donor and (2) the transport of the water- soluble analog may
provide an experimental approach to assay the hypothetical "flippase"
proposed to mediate the transbilayer movement of Glc-P-Dol from the
cytoplasmic face of the ER to the lumenal monolayer.
相似文献
107.
108.
Yan Dong Ralph K. Rosenbaum Michael Z. Hauschild 《The International Journal of Life Cycle Assessment》2018,23(8):1641-1653
Purpose
The study develops site-dependent characterization factors (CFs) for marine ecotoxicity of metals emitted to freshwater, taking their passage of the estuary into account. To serve life cycle assessment (LCA) studies where emission location is often unknown, site-generic marine CFs were developed for metal emissions to freshwater and coastal seawater, respectively. The new CFs were applied to calculate endpoint impact scores for the same amount of metal emission to each compartment, to compare the relative ecotoxicity damages in freshwater and marine ecosystems in LCA.Methods
Site-dependent marine CFs for emission to freshwater were calculated for 64 comparatively independent seas (large marine ecosystems, LMEs). The site-dependent CF was calculated as the product of fate factor (FF), bioavailability factor (BF), and effect factor (EF). USEtox modified with site-dependent parameters was extended with an estuary removal process to calculate FF. BF and EF were taken from Dong et al. Environ Sci Technol 50:269–278 (2016). Site-generic marine CFs were derived from site-dependent marine CFs. Different averaging principles were tested, and the approach representing estuary discharge rate was identified as the best one. Endpoint marine and freshwater metals CFs were developed to calculate endpoint ecotoxicity impact scores.Results and discussion
Marine ecotoxicity CFs are 1.5 orders of magnitude lower for emission to freshwater than for emission to seawater for Cr, Cu, and Pb, due to notable removal fractions both in freshwater and estuary. For the other metals, the difference is less than half an order of magnitude, mainly due to removal in freshwater. The site-dependent CFs generally vary within two orders of magnitude around the site-generic CF. Compared to USES-LCA 2.0 CFs (egalitarian perspective), the new site-generic marine CFs for emission to seawater are 1–4 orders of magnitude lower except for Pb. The new site-generic marine CFs for emission to freshwater lie within two orders of magnitude difference from USES-LCA 2.0 CFs. The comparative contribution share analysis shows a poor agreement of metal toxicity ranking between both methods.Conclusions
Accounting for estuary removal particularly influences marine ecotoxicity CFs for emission to freshwater of metals that have a strong tendency to complex-bind to particles. It indicates the importance of including estuary in the characterization modelling when dealing with those metals. The resulting endpoint ecotoxicity impact scores are 1–3 orders of magnitude lower in seawater than in freshwater for most metals except Pb, illustrating the higher sensitivity of freshwater ecosystems to metal emissions, largely due to the higher species density there.109.
Mattia Damiani Montserrat Núñez Philippe Roux Eléonore Loiseau Ralph K. Rosenbaum 《The International Journal of Life Cycle Assessment》2018,23(10):2071-2088