Phylogenetic significance of the kinethmoid‐associated Y‐shaped ligament and long intercostal ligaments in the Cypriniformes (Actinopterygii: Ostariophysi)

Liao, T.Y. & Kullander, S.O. (2012). Phylogenetic significance of the kinethmoid‐associated Y‐shaped ligament and long intercostal ligaments in the Cypriniformes (Actinopterygii: Ostariophysi). —Zoologica Scripta, 42, 71–87. The phylogenetic significance of the Y‐shaped and long intercostal ligaments in the Cypriniformes is examined using character optimization in 184 species representing 20 non‐ostariophysan teleost species, five ostariophysan orders, seven cypriniform families and 14 cyprinid subfamilies. Character states were optimized on the phylogenetic trees of previous studies. Given the topology of Saitoh et al. (2011) , the Y‐shaped ligament, connecting the kinethmoid to the ethmoid complex, is shown to be a synapomorphy for the Cyprinidae, with reversals observed in the Cyprininae, Danioninae, Gobioninae and Psilorhynchinae. The condition of the Y‐shaped ligament is consistent within most subfamilies with a few exceptions. Despite the exceptions, the Y‐shaped ligament may be considered as a diagnostic character distinguishing cyprinid subfamilies with otherwise similar morphology, that is, the Danioninae and Opsariichthyinae. The long intercostal ligament, connecting five to eight ribs and ascending from the subdistal end of the fifth rib, is present in the Catostomidae and all cyprinid subfamilies, except for the Psilorhynchinae and two developmentally truncated genera, Danionella and Paedocypris. In addition to these two cypriniforme families, the long intercostal ligament is homoplastically present in some catfishes. Given the topology of Saitoh et al. (2011) , presence of the long intercostal ligament is a synapomorphy of Cyprinidae+Catostomidae. Some shorter ligaments are also present in the Cypriniformes and Chilodus gracilis (Characiformes), near the base of the anterior ribs and only occurring anterodorsally to the putative line of the long intercostal ligament even when it is absent.     

苜蓿叶片水杨酸含量与其蓟马抗性的关系

采用不同抗蓟马特性的苜蓿品系,于不同蓟马虫口密度下测定苜蓿水杨酸含量和虫害程度,以明确苜蓿叶片水杨酸含量与其抗蓟马特性的关系.结果表明,苜蓿叶片游离态、结合态水杨酸含量均与苜蓿抗蓟马特性密切相关;高抗品系(抗蓟马品系)的水杨酸初始含量(0.539 mg·g-1)高于低抗品系(0.403 mg·g-1);与较低抗品系相比,高抗品系受害器官(叶)水杨酸含量随虫口密度和危害点面积的增大而增加相对缓慢,而随危害指数的增大而增加较快(3.84倍).可见,水杨酸主要是间接增强苜蓿对蓟马的抗性;高抗蓟马苜蓿品系能通过快速获得较高水杨酸含量来阻碍被危害伤口的扩大,降低其受危害程度,促使自身产量和品质提高.     

The European Renal Genome Project: An Integrated Approach Towards Understanding the Genetics of Kidney Development and Disease

Rapid progress in genome research creates a wealth of information on the functional annotation of mammalian genome sequences. However, as we accumulate large amounts of scientific information we are facing problems of how to integrate and relate the data produced by various genomic approaches. Here, we propose the novel concept of an organ atlas where diverse data from expression maps to histological findings to mutant phenotypes can be queried, compared and visualized in the context of a three-dimensional reconstruction of the organ. We will seek proof of concept for the organ atlas by elucidating genetic pathways involved in development and pathophysiology of the kidney. Such a kidney atlas may provide a paradigm for a new systems-biology approach in functional genome research aimed at understanding the genetic bases of organ development, physiology and disease.Key Words: EuReGene, kidney, genome, development, pathophysiology, genetics     

Rejecting strictly allopatric speciation on a continental island: prolonged postdivergence gene flow between Taiwan (Leucodioptron taewanus,Passeriformes Timaliidae) and Chinese (L. canorum canorum) hwameis

Allopatry is conventionally considered the geographical mode of speciation for continental island organisms. However, strictly allopatric speciation models that assume the lack of postdivergence gene flow seem oversimplified given the recurrence of land bridges during glacial periods since the late Pliocene. Here, to evaluate whether a continental island endemic, the Taiwan hwamei (Leucodioptron taewanus, Passeriformes Timaliidae) speciated in strict allopatry, we used weighted‐regression‐based approximate Bayesian computation (ABC) to analyse the genetic polymorphism of 18 neutral nuclear loci (total length: 8500 bp) in Taiwan hwamei and its continental sister species, the Chinese hwamei (L. canorum canorum). The nonallopatry model was found to fit better with observed genetic polymorphism of the two hwamei species (posterior possibility = 0.82). We also recovered unambiguous signals of nontrivial bidirectional postdivergence gene flow (N_em » 1) between Chinese hwamei and Taiwan hwamei until 0.5 Ma. Divergence time was estimated to be 3.5 to 2 million years earlier than that estimated from mitochondrial cytochrome b sequences. Finally, using the inferred nonallopatry model to simulate genetic variation at 24 nuclear genes examined showed that the adiponectin receptor 1 gene may be under divergent adaptation. Our findings imply that the role of geographical barrier may be less prominent for the speciation of continental island endemics, and suggest a shift in speciation studies from simply correlating geographical barrier and genetic divergence to examining factors that facilitate and maintain divergence, e.g. differential selection and sexual selection, especially in the face of interpopulation gene flow.     

Improved gold chloride staining method for anatomical analysis of sensory nerve endings in the shoulder capsule and labrum as examples of loose and dense fibrous tissues

Consistency in gold chloride staining is essential for anatomical analysis of sensory nerve endings. The gold chloride stain for this purpose has been modified by many investigators, but often yields inconsistent staining, which makes it difficult to differentiate structures and to determine nerve ending distribution in large tissue samples. We introduce additional steps and major changes to the modified Gairns’ protocol. We controlled the temperature and mixing rate during tissue staining to achieve consistent staining and complete solution penetration. We subjected samples to sucrose dehydration to improve cutting efficiency. We then exposed samples to a solution containing lemon juice, formic acid and paraformaldehyde to produce optimal tissue transparency with minimal tissue deformity. We extended the time for gold chloride impregnation 1.5 fold. Gold chloride was reduced in the labrum using 25% formic acid in water for 18 h and in the capsule using 25% formic acid in citrate phosphate buffer for 2 h. Citrate binds gold nanoparticles, which minimizes aggregation in the tissue. We stored samples in fresh ultrapure water at 4° C to slow reduction and to maintain color contrast in the tissue. Tissue samples were embedded in Tissue Tek and sectioned at 80 and 100 μm instead of using glycerin and teasing the tissue apart as in Gairns’ modified gold chloride method. We attached sections directly to gelatin subbed slides after sectioning with a cryostat. The slides then were processed and coverslipped with Permount. Staining consistency was demonstrated throughout the tissue sections and neural structures were clearly identifiable.     

Isolation and characterization of 12 tetranucleotide repeat microsatellite loci from the green‐backed tit (Parus monticolus)

From a partial genomic library enriched for GATA short tandem repeats, we developed 12 polymorphic microsatellite loci from the green‐backed tit (Parus monticolus). We characterized these loci by genotyping 30 adult individuals with unknown relationship. The number of alleles ranged from four to 17 per locus (mean = 9.3 alleles) and the observed heterozygosity for each locus ranged from 0.633 to 0.933 (mean = 0.789). All loci conformed to Hardy–Weinberg expectations. Four of 66 possible pairwise comparisons between loci showed significant gametic disequilibrium.