Toad-headed Lizard Phrynocephalus forsythii(Squamata,Agamidae)as a Potential Ring Species Inferred from Population Genetic Differentiation

Speciation has never been directly observed in nature because it is a lengthy phenomenon.Although rare,ring species are an optimal natural example of speciation and can be identified through the assessment of the geographical conditions of their potential habitat.Phrynocephalus forsythii is endemic to the Tarim Basin,which compnses the Taklamakan Desert and surrounded by mountains on three sides.This study aimed to determine whether P.forsythii had a ring-species-like divergence pattern through the characterization of the genetic features of 17 populations covering the major distribution of this species.Species distribution modelling revealed that P.forsythii had a continuous circular distribution around the Tarim Basin.Gene flow was observed in most adjacent populations except for two terminal populations of the ring,which exhibit the highest differentiation.Genetic distance and geographic distance were significantly correlated,indicating that the observed differentiation resulted from genetic variation gradually accumulating during population dispersion.Although our results do not definitively indicate that P.forsythii is a ring species,our results indicate a ring-shaped diversification This phenomenon elucidates the potential mechanism underlying speciation in the presence of gene flow,providing insight into this evolutionary process.

THE AUTOMATIC GENERATION OF LIMIT STATE FUNCTION OF HINGED STRUCTURE

In this paper, the theorem of structure continual variation of truss structure in the analysis of structure reliability is derived, and it is used to generate limit state function automatically. We can avoid repeated assembly of global stiffness matrix and repeated inverse operations of the matrix caused by constant changes of structure topology. A new criterion of degenerate of the structure into mechanism is introduced. The calculation examples are satisfactory.

ON GENERALIZED FEYNMAN-KAC TRANSFORMATION FOR MARKOV PROCESSES ASSOCIATED WITH SEMI-DIRICHLET FORMS

Suppose that X is a right process which is associated with a semi-Dirichlet form （ε, D（ε）） on L2（E; m）. Let J be the jumping measure of （ε, D（ε）） satisfying J（E x E- d） 〈 ∞. Let u E D（ε）b ：= D（ε） N L（E; m）, we have the following Pukushima＇s decomposition u（Xt）-u（X0） --- Mut ＋ Nut. Define Pu f（x） = Ex[eNT f（Xt）]. Let Qu（f,g） = ε（f,g）＋ε（u, fg） for f, g E D（ε）b. In the first part, under some assumptions we show that （Qu, D（ε）b） is lower semi-bounded if and only if there exists a constant a0 〉 0 such that /Put/2 ≤eaot for every t 〉 0. If one of these assertions holds, then （Put〉0is strongly continuous on L2（E;m）. If X is equipped with a differential structure, then under some other assumptions, these conclusions remain valid without assuming J（E x E - d） 〈 ∞. Some examples are also given in this part. Let At be a local continuous additive functional with zero quadratic variation. In the second part, we get the representation of At and give two sufficient conditions for PAf（x） = Ex[eAtf（Xt）] to be strongly continuous.

Epistatic interactions between pterin and carotenoid genes modulate intra-morph color variation in a lizard

Color polymorphisms have become a major topic in evolutionary biology and substantial efforts have been devoted to the understanding of the mechanisms responsible for originating such colorful systems.Within-morph continuous variation,on the other hand,has been neglected in most of the studies.Here,we combine spectrophotometric/visual modeling and genetic data to study the mechanisms promoting continuous variation within categorical color morphs of Podarcis muralis.Our results suggest that intra-morph variability in the pterin-based orange morph is greater compared to white and yellow morphs.We also show that continuous variation within the orange morph is partially discriminable by conspecifics.Genotyping results indicate that allelic variants at the BCO2 locus(responsible for deposition of yellow carotenoids)contribute to generate continuous variation in orange individuals.However,other intrinsic and/or extrinsic mechanisms,such as body size,might be involved,opening a new avenue for future research on the drivers of continuous variation within-morphs.

Some Theorems in the Theory of Microstretch Thermomagnetoelectroelasticity

The linear dynamic theory of microstretch thermomagnetoelectroelasticity is studied in this paper.First,a reciprocity relation which involves two processes at different instants is established to form the basis of a uniqueness result and a reciprocal theorem.The proof of the reciprocal theorem avoids both using the Laplace transform and incorporating the initial conditions into the equations of motion.The uniqueness theorem is derived with no definiteness assumption on the elastic constitutive coefficients.Then the continuous dependence theorem is discussed upon two external data systems.Finally,the variational principle of Hamilton type which fully characterizes the solution of the mixed boundary-initial-value problem（mixed problem） is obtained.These theorems lay a solid foundation for further theoretical and numerical studies on microstretch thermomagnetoelectroelastic materials.