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171.
Giacomo Potente tienne Lveill-Bourret Narjes Yousefi Rimjhim Roy Choudhury Barbara Keller Seydina Issa Diop Daniël Duijsings Walter Pirovano Michael Lenhard Pter Szvnyi Elena Conti 《Molecular biology and evolution》2022,39(2)
Supergenes are nonrecombining genomic regions ensuring the coinheritance of multiple, coadapted genes. Despite the importance of supergenes in adaptation, little is known on how they originate. A classic example of supergene is the S locus controlling heterostyly, a floral heteromorphism occurring in 28 angiosperm families. In Primula, heterostyly is characterized by the cooccurrence of two complementary, self-incompatible floral morphs and is controlled by five genes clustered in the hemizygous, ca. 300-kb S locus. Here, we present the first chromosome-scale genome assembly of any heterostylous species, that of Primula veris (cowslip). By leveraging the high contiguity of the P. veris assembly and comparative genomic analyses, we demonstrated that the S-locus evolved via multiple, asynchronous gene duplications and independent gene translocations. Furthermore, we discovered a new whole-genome duplication in Ericales that is specific to the Primula lineage. We also propose a mechanism for the origin of S-locus hemizygosity via nonhomologous recombination involving the newly discovered two pairs of CFB genes flanking the S locus. Finally, we detected only weak signatures of degeneration in the S locus, as predicted for hemizygous supergenes. The present study provides a useful resource for future research addressing key questions on the evolution of supergenes in general and the S locus in particular: How do supergenes arise? What is the role of genome architecture in the evolution of complex adaptations? Is the molecular architecture of heterostyly supergenes across angiosperms similar to that of Primula? 相似文献
172.
PAUL EGGLETON ROBERT BELSHAW 《Biological journal of the Linnean Society. Linnean Society of London》1993,48(3):213-226
We consider differences between dipteran, hymenopteran and coleopteran parasitoids in the following categories: taxonomic range and developmental stage of hosts attacked; habitats they are attacked in; developmental stage of the parasitoid contacting the host; occurrence of phoresy, and attacking hosts during flight. Using existing phylogenetic classifications we reconstruct possible ancestral conditions to the parasitoid clades in the three orders. By considering these as phylogenetic constraints and potentialities we attempt to account for the observed differences between the parasitoids within the orders. 相似文献
173.
CRISTIAN R. ALTABA 《Zoological Journal of the Linnean Society》1993,107(1):73-90
Whole-animal anatomy is used in a cladistic analysis of five genera of brackish-water hydrobiids living in the western Atlantic. Antillobia margalefi gen. & sp. nov. (Hydrobiidae: Littoridininae) is described based on specimens from Lago Enriquillo, an inland saline lake in the Dominican Republic. The topology ( Hydrobia ( Spurwinkia ( Heleobia ( Heleobops ( Antillobia ))))) is considerably better than any alternative. Among 27 characters and a total of 39 character states used in the analysis, only two convergences are detected, and these involve the genitalia. Detailed anatomical data are shown to be necessary to assess relationships in the presence of constraints on morphological evolution imposed by a very small size. 相似文献
174.
Populations exposed to different ecological environments should diverge for phenotypic traits that influence survival and reproduction. This adaptive divergence should reduce gene flow between populations because immigrants become less fit than residents and because hybrids perform poorly in either environment (i.e., ecologically-dependent reproductive isolation). Here I demonstrate adaptive divergence and the evolution of reproductive isolation in populations of sockeye salmon (Oncorhynchus nerka) introduced from a common ancestral source into a new lake system (Lake Washington, Washington). The introduced fish founded several new populations, two of which experience very different environments during breeding and early development (Cedar River v.s. Pleasure Point beach). Over 13 generations, the two populations diverged for adult traits (female body size, male body depth; measured in the wild) and embryo traits (survival to hatching, development rate, size at emergence; measured in a common environment). The rates of divergence for these characters were similar to those observed in other examples of rapid evolution, and can best be attributed to natural selection. Partial reproductive isolation has evolved in concert with adaptive divergence: the rate of exchange of adults between the populations (determined using natural tags) is higher than the rate of gene flow (determined using DNA microsatellites). The demonstration that adaptive divergence can initiate reproductive isolation in less than 13 generations suggests that the first signs of ecological speciation may appear soon after new environments are first colonized. 相似文献
175.
Winther RG 《Journal of the history of biology》2001,34(3):517-555
August Weismann is famous for having argued against the inheritance of acquired characters. However, an analysis of his work
indicates that Weismann always held that changes in external conditions, acting during development, were the necessary causes
of variation in the hereditary material. For much of his career he held that acquired germ-plasm variation was inherited. An irony, which is in tension with much of the standard twentieth-century history of biology, thus exists – Weismann
was not a Weismannian. I distinguish three claims regarding the germ-plasm: (1) its continuity,(2) its morphological sequestration,
and (3) its variational sequestration. With respect to changes in Weismann's views on the cause of variation, I divide his
career into four stages. For each stage I analyze his beliefs on the relative importance of changes in external conditions
and sexual reproduction as causes ofvariation in the hereditary material. Weismann believed, and Weismannism denies, that
variation, heredity, and development were deeply intertwined processes. This article is part of a larger project comparing
commitments regarding variation during the latter half of the nineteenth century.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
176.
177.
Endosymbiont phylogenesis in the dryophthoridae weevils: evidence for bacterial replacement 总被引:7,自引:0,他引:7
Lefèvre C Charles H Vallier A Delobel B Farrell B Heddi A 《Molecular biology and evolution》2004,21(6):965-973
Intracellular symbiosis is widespread in the insect world where it plays an important role in evolution and adaptation. The weevil family Dryophthoridae (Curculionoidea) is of particular interest in intracellular symbiosis evolution with regard to the great economical and ecological features of these invasive insects, and the potential for comparative studies across a wide range of host plants and environments. Here, we have analyzed the intracellular symbiotic bacteria of 19 Dryophthoridae species collected worldwide, representing a wide range of plant species and tissues. All except one (Sitophilus linearis) harbor symbiotic bacteria within specialized cells (the bacteriocytes) assembled as an organ, the bacteriome. Phylogenetic analysis of the 16S rDNA gene sequence of the Dryophthoridae endosymbionts revealed three endosymbiotic clades belonging to gamma3-Proteobacteria and characterized by different GC contents and evolutionary rate. The genus name Candidatus Nardonella was proposed for the ancestral clade infesting Dryophthoridae 100 MYA and represented by five of nine bacterial genera studied. For this clade showing low GC content (40.5% GC) and high evolutionary rate (0.128 substitutions/site per 100 Myr), a single infection and subsequent cospeciation of the host and the endosymbionts was observed. In the two other insect lineage endosymbionts, with relatively high GC content (53.4% and 53.8% GC), competition with ancestral pathogenic bacteria might have occurred, leading to endosymbiont replacement in present-day last insects. 相似文献
178.
Frénal K Xu CQ Wolff N Wecker K Gurrola GB Zhu SY Chi CW Possani LD Tytgat J Delepierre M 《Proteins》2004,56(2):367-375
The gamma-KTx-type scorpion toxins specific for K+ channels were found to interact with ERG channels on the turret region, while alpha-KTx3.2 Agitoxin-2 binds to the pore region of the Shaker K+ channel, and alpha-KTx5.3 BmP05 binds to the intermediate region of the small-conductance calcium-activated K-channel (SK(Ca)). In order to explore the critical residues for gamma-KTx binding, we determined the NMR structure of native gamma-KTx1.1 (CnErg1), a 42 amino acid residues scorpion toxin isolated from the venom of the Mexican scorpion Centruro?des noxius Hoffmann, and we used computational evolutionary trace (ET) analysis to predict possible structural and functional features of interacting surfaces. The 1H-NMR three-dimensional solution structure of native ergtoxin (CnErg1) was solved using a total of 452 distance constraints, 13 3J(NH-Halpha) and 10 hydrogen bonds. The structure is characterized by 2 segments of alpha-helices and a triple-stranded antiparallel beta-sheet stabilized by 4 disulfide bridges. The ET and structural analysis provided indication of the presence of two important amino acid residue clusters, one hydrophobic and the other hydrophilic, that should be involved in the surface contact between the toxin and the channel. Some features of the proposed interacting surface are discussed. 相似文献
179.
180.
Wulf-Peter?SchmidtEmail author Elisabeth?Dahlqvist Matthias?Finkbeiner Stephan?Krinke Silvia?Lazzari Dirk?Oschmann Sophie?Pichon Christian?Thiel 《The International Journal of Life Cycle Assessment》2004,9(6):405-416
Goal, Scope and Background The automotive industry has a long history in improving the environmental performance of vehicles - fuel economy and emission
improvements, introduction of recycled and renewable materials, etc. The European Union also aims at improving the environmental
performance of products by reducing, in particular, waste resulting from End-of-Life Vehicles (ELVs) for example. The European
Commission estimates that ELVs contribute to approximately 1 % of the total waste in Europe [9]. Other European Union strategies
are considering more life cycle aspects, as well as other impacts including resource or climate change. This article is summarizing
the results of a European Commission funded project (LIRECAR) that aims at identifying the environmental impacts and relevance
for combinations of recycling / recovery and lightweight vehicle design options over the whole life cycle of a vehicle - i.e.
manufacturing, use and recycling/recovery. Three, independent and scientific LCA experts reviewed the study according to ISO
14040. From the beginning, representatives of all Life Cycle Stakeholders have been involved (European materials & supplier
associations, an environmental Non-Governmental Organization, recycler’s association).
Model and System Definition The study compared 3 sets of theoretical vehicle weight scenarios: 1000 kg reference (material range of today’s end-of-life,
mid-sized vehicles produced in the early 1990’s) and 2 lightweight scenarios for 100 kg and 250 kg less weight based on reference
functions (in terms of comfort, safety, etc.) and a vehicle concept. The scenarios are represented by their material range
of a broad range of lightweight strategies of most European car manufacturers. In parallel, three End-of-Life (EOL) scenarios
are considered: EOL today and two theoretical extreme scenarios (100% recycling, respectively, 100% recovery of shredder residue
fractions that are disposed of today). The technical and economical feasibility of the studied scenarios is not taken into
consideration (e.g. 100% recycling is not possible).
Results and Discussion Significant differences between the various, studied weight scenarios were determined in several scenarios for the environmental
categories of global warming, ozone depletion, photochemical oxidant creation (summer smog), abiotic resource depletion, and
hazardous waste. However, these improvement potentials can be only realized under well defined conditions (e.g. material compositions,
specific fuel reduction values and EOL credits) based on case-by-case assessments for improvements over the course of the
life cycle. Looking at the studied scenarios, the relative contribution of the EOL phase represents 5% or less of the total
life cycle impact for most selected impact categories and scenarios. The EOL technology variations studied do not impact significantly
the considered environmental impacts. Exceptions include total waste, as long as stockpile goods (overburden, tailings and
ore/coal processing residues) and EOL credits are considered.
Conclusions and Recommendations LIRECAR focuses only on lightweight/recycling, questions whereas other measures (changes in safety or comfort standards, propulsion
improvements for CO2, user behavior) are beyond the scope of the study. The conclusions are also not necessarily transferable to other vehicle
concepts. However, for the question of end-of-life options, it can be concluded that LIRECAR cannot support any general recommendation
and/or mandatory actions to improve recycling if lightweight is affected. Also, looking at each vehicle, no justification
could be found for the general assumption that lightweight and recycling greatly influence the affected environmental dimension
(Global Warming Potential or resource depletion and waste, respectively). LIRECAR showed that this general assumption is not
true under all analyzed circumstances and not as significant as suggested. Further discussions and product development targets
shall not focus on generic targets that define the approach/technology concerned with how to achieve environmental improvement
(weight reduction [kg], recycling quota [%]), but on overall life cycle improvement). To enable this case-by-case assessment,
exchanges of necessary information with suppliers are especially relevant. 相似文献