Chromosome variability in the Lemuridae

Chromosome studies have been conducted in Lemur catta, L. macaco, L. mongoz, L. fulvus fulvus, and a hybrid L. fulvus fulvus x L. fulvus albifrons. Comparative analysis shows that inter- and intraspecific chromosome variability is a common finding in Lemurs. The Lemuridae are divided into three groups according to the characteristics of their chromosome complement. A reclassification of L. catta with the Hapalemurs is suggested, based on chromosomal and nonchromosomal data.     

Variations of the mandibular shape in extant hominoids: Generic, specific, and subspecific quantification using elliptical fourier analysis in lateral view

While a number of studies have documented the mandibular variations in hominoids, few focused on evaluating the variation of the whole outline of this structure. Using an efficient morphometrical approach, i.e. elliptical Fourier analysis, mandibular outlines in lateral view from 578 adult hominoids representing the genera Hylobates, Pongo, Gorilla, Pan, and Homo were quantified and compared. This study confirms that elliptical Fourier analysis provides an accurate characterization of the shape of the mandibular profile. Differences in mandibular shape between hominoid genera, species, subspecies, and to a lesser extent between sexes were demonstrated. Mandibles in great apes and hylobatids subspecies were generally less distinct from each other than were species. However, the magnitudes of differences among subspecies of Gorilla and Pongo approached or exceeded those between Pan troglodytes and P. paniscus. The powerful discrimination between taxa from the genus down to subspecific level associated to the relatively low level of intrageneric mandibular polymorphism in great apes provides strong evidences in support of the taxonomic utility of the shape of the mandibular profile in hominoids. In addition, morphological affinities between Pongo and Pan and the clear distinction between Homo and Pan suggest that the mandibular outline is a poor estimate of phylogenetic relationships in great apes and humans. The sexual dimorphism in mandibular shape exhibits two patterns of expression: a high degree of dimorphism in Gorilla, Pongo, and H. s. syndactylus and a relatively low one in modern humans and Pan. Besides, degree of mandibular shape dimorphism can vary considerably among closely related subspecies as observed in gorillas, arguing against the use of mandibular shape dimorphism patterns as characters in phylogenetic analyses. However, the quantification of the mandibular shape and of the variations among hominoids provides an interesting comparative framework that is likely to supply further arguments for a better understanding of the patterns of differentiation between living hominoids.     

基于椭圆傅里叶分析的次南极电灯鱼矢耳石形态多样性

次南极电灯鱼矢耳石形态特征具有多样性.为了深入研究其形态特征,利用南设得兰群岛外侧水域采集的456尾次南极电灯鱼(体长范围6.0～8.8 cm)样本,对其矢耳石形态进行分析和判别.根据形态特征将次南极电灯鱼耳石分为4种类型,并采用椭圆傅里叶分析法选取表征耳石类型的77个傅里叶特征系数进行了分析.结果表明: 对4种耳石类型两两比较后发现,具有显著性差异的傅里叶特征系数最多及最少分别占总体的61%和28.6%;对77个傅里叶系数进行主成分分析,前22个主成分解释了总变异的76.6%;选取了17个傅里叶特征系数进行判别分析,建立判别函数,总体判别率为87.2%;根据椭圆傅里叶分析重建的耳石轮廓反映了4种耳石类型间的差异.4种耳石类型在不同体长及体质量的次南极电灯鱼中皆有出现,表明耳石类型具有随机性,且左右耳石类型不一致,表明其左右耳石外形具有差异性.4种耳石类型中,Ⅰ型和Ⅱ型占总体的72.6%,为次南极电灯鱼耳石的主要形态;Ⅲ型和Ⅳ型占总体的27.4%,为次要形态.     

Shape analysis of tumor cell nuclei in ependymomas by means of Fourier analysis

OBJECTIVE: To study the prognostic significance of nuclear shape analysis in ependymomas. STUDY DESIGN: Tumor cell nuclei in surgical specimens of primary resected ependymomas from 30 patients were evaluated by means of Fourier analysis of nuclear contours, conventional morphometric features (nuclear area, shape factor) and the Ki-67 proliferation index. Fourier analysis can be used for decomposing an irregular nuclear contour by calculating "Fourier amplitudes." Tumors with different tumor grades according to the World Health Organization were compared, as were patients with and without recurrence of ependymomas. Planimetric data were further correlated with the Ki-67 index. RESULTS: t Test and multivariate analysis showed distinct differences between ependymomas with tumor grade 3 and the other tumor grades. Cross-validated, stepwise discriminant analysis with the event of recurrence as grouping variable revealed correct reclassification in 16/18 cases without recurrence and of 10/12 cases with recurrence. When considering just intracranial ependymomas with total surgical removal, Fourier amplitudes provided 100% correct reclassification concerning recurrence. Proliferation index, in contrast, showed considerable overlap between all tumor grades and between cases with and without recurrence. CONCLUSION: Quantification of the shape of tumor cell nuclei in ependymomas by means of Fourier analysis has prognostic significance and seems to be superior to the Ki-67 index.     

Shape differentiation and characterization in the two morphotypes of the Antarctic limpet Nacella concinna using Elliptic Fourier analysis of shells

The Antarctic limpet Nacella concinna (Strebel 1908) presents two ecotypes (littoral and sublittoral) differing in morphological and behavioral characteristics and more recently discovered, in physiological traits and genetic population structure. Previous works, based on traditional morphometry, used only three measurements (length, width and height of the shell) and their relationships. However, this methodology could not describe in detail the shape of the morphotypes. In the present work, Elliptic Fourier analysis (EFA) of shells was used to study the shape of the two morphotypes in six localities along the Antarctic Peninsula. The use of EFA confirmed the morphometric differences. The littoral morphotype has higher and globose shells with the apex displaced to the anterior part; the sublittoral individuals are more flat and pointed, and have the apex very well defined. Low allometric effect was detected in SL individuals, whereas L specimens did not show an allometric relationship within the examined size range. Differences in shell shape among localities were recorded. EFA analysis reflected the overall shell shape and allowed to characterize the main differences in shell shape between ecotypes that were difficult to quantify using the standard morphometric approach.     

Shape variation in the mandibular symphysis of apes: An application of a median axis method

Symphyseal contours in a sample of living and fossil apes were assessed by application of the line skeleton, a form of median axis transformation. While the line skeleton offers novel opportunities for the analysis of shape, this study reaffirms previous observations that the shape of the symphysis is highly variable within great ape species, such that symphyseal morphology is not useful as a taxonomic marker. There is also little indication that symphyseal shape differs significantly between the sexes. The perception of what constitutes a salient superior or inferior transverse torus among living apes appears to be dependent on the expression of the genioglossal fossa. © 1993 Wiley-Liss, Inc.     

Highly repeated DNA analysis and systematics of the Lemuridae,a family of Malagasy prosimians

Hybridization of highly repeated DNA sequences ofEulemur fulvus mayottensis, Lemur catta, andVarecia has been performed on blots of different species of Lemuridae (L. catta, Hapalemur griseus, Varecia variegata variegata, V. v. rubra, E. macaco macaco, E. coronatus, E. mongoz, andE. rubriventer). The probe ofE. fulvus only hybridized with the differentEulemur species, whereas that ofVarecia hybridized with the two subspecies ofVarecia and that ofL. catta with bothL. catta andHapalemur. These results were used to confirm the classification ofVarecia in a separate genus and to review the separation of theL. catta/Hapalemur group from the other species ofEulemur. Comparison of the migration patterns from DNA fragments of these different species has been used to propose a cladogram of the differentEulemur species.     

Intraspecific variability of pollen morphology as revealed by elliptic Fourier analysis

Pollen grains have long fascinated biologists who used their remarkable interspecific diversity as a marker to infer profiles of past and present vegetations and environment. This study addresses the question of the diversity of the morphology of pollen grains at the intraspecific level: how different are pollen grains of the same species sampled in different populations? Such differences are expected, and are actually well known to palynologists, but at the same time technically challenging to quantify. We used elliptic Fourier analysis, a powerful morphometric approach for the comparison of outlines, on equatorial and polar views of 30 pollen grains sampled in two different populations for each of five tropical species, thus yielding 600 outlines. Multivariate analysis of variance revealed intraspecific variation of shape of the pollen grains in three out of the five species studied. Our goal here was to test if there were differences in the shape of pollen. This, to our knowledge, would be the first such study of this particular aspect of palynology. We also discuss some relevant evolutionary hypotheses. Further studies using outline analysis, coupled with a choice of appropriate sampling strategies, to suit varying environmental conditions, would prove of great value in testing such hypotheses.     

Cranial and mandibular morphology of the Indrinae. Contribution of Procrustes methods and Fourier analysis

Although it is universally accepted that the Indridae family is monophyletic, there is no such unanimity about how the extant species of the Indrinae sub-family are related. Cranium and mandible disparity among Indri indri, Propithecus diadema, Propithecus verreauxi and Avahi laniger is analysed by geometrical morphometric methods and interpreted in adaptive terms. We compare results obtained by two techniques: Procrustes superimpositions for skulls and elliptical Fourier analysis for jawbones. In both studies, the three genera are clearly isolated. Avahi laniger is the species with the most paedomorphic cranium while Indri indri has the most 'juvenile' mandible. Cranial morphology is governed principally by orbit volume and body size, while jaw shape is related to diet (enlargement of the gonial region).     

How is dispersal integrated in life histories: a quantitative analysis using butterflies

As dispersal plays a key role in gene flow among populations, its evolutionary dynamics under environmental changes is particularly important. The inter-dependency of dispersal with other life history traits may constrain dispersal evolution, and lead to the indirect selection of other traits as a by-product of this inter-dependency. Identifying the dispersal's relationships to other life-history traits will help to better understand the evolutionary dynamics of dispersal, and the consequences for species persistence and ecosystem functioning under global changes. Dispersal may be linked to other life-history traits as their respective evolutionary dynamics may be inter-dependent, or, because they are mechanistically related to each other. We identify traits that are predicted to co-vary with dispersal, and investigated the correlations that may constrain dispersal using published information on butterflies. Our quantitative analysis revealed that (1) dispersal directly correlated with demographic traits, mostly fecundity, whereas phylogenetic relationships among species had a negligible influence on this pattern, (2) gene flow and individual movements are correlated with ecological specialisation and body size, respectively and (3) routine movements only affected short-distance dispersal. Together, these results provide important insights into evolutionary dynamics under global environmental changes, and are directly applicable to biodiversity conservation.     

Rapid quantitative analysis using a single molecule counting approach

Single molecule detection of target molecules specifically bound by paired fluorescently labeled probes has shown great potential for sensitive quantitation of biomolecules. To date, no reports have rigorously evaluated the analytical capabilities of a single molecule detection platform employing this dual-probe approach or the performance of its data analysis methodology. In this paper, we describe a rapid, automated, and sensitive multicolor single molecule detection apparatus and a novel extension of coincident event counting based on detection of fluorescent probes. The approach estimates the number of dual-labeled molecules of interest from the total number of coincident fluorescent events observed by correcting for unbound probes that randomly pass through the interrogation zone simultaneously. Event counting was evaluated on three combinations of distinct fluorescence channels and was demonstrated to outperform conventional spatial cross-correlation in generating a wider linear dynamic response to target molecules. Furthermore, this approach succeeded in detecting subpicomolar concentrations of a model RNA target to which fluorescently labeled oligonucleotide probes were hybridized in a complex background of RNA. These results illustrate that the fluorescent event counting approach described represents a general tool for rapid sensitive quantitative analysis of any sample analyte, including nucleic acids and proteins, for which pairs of specific probes can be developed.     

Shape variability in tridactyl dinosaur footprints: the significance of size and function

The functional anatomy of the hindlimb of bipedal dinosaurs has been intensively studied. Yet, surprisingly little work has been done concerning functional adaptation of digits for terrestrial locomotion. While complete and articulated pes skeletons are scarce, pes shape is abundantly recorded by fossil footprints. We elucidate the significance of footprint shape and size for locomotion using a large sample (n = 303) of tridactyl dinosaur footprints from a broad range of geographical localities and time slots. Size and shape variation are characterized separately for theropods and ornithischians, the two principal trackmaker taxa. At smaller sizes, theropod footprints are best discriminated from ornithischian footprints by their smaller interdigital angle and larger projection of digit III; at larger sizes digital widths are effective discriminants. Ornithischian footprints increase in size from the Early Jurassic to the Late Cretaceous, a trend not observed in theropod footprints. Size and function are argued to be important determinants of footprint shape, and an attempt made to infer function from shape. Digit III projection and length-to-width ratio of the footprints are negatively correlated with size in both groups; digit impression width is positively correlated with size only in ornithischians. Digit III projection appears to be positively correlated with cursorial ability. Increased interdigital angles are associated with a decrease in digital width, possibly an adaptation for stability. Weak digit III projection and increased digital width are interpreted as adaptations for graviportality. Footprints yield great potential for the understanding of the functional morphology of dinosaur feet.     

基于GIS的农田土壤、作物特征空间变异性及其相互关系

The objective of this research was to investigate the variability and the quantitative relationships among soil nutrients and crop growth status and yield. All data were analyzed by both classical statistics and geostatistics based on GIS. Soil properties included soil pH, total N, organic matter, available P and available K, while crop growth status was indicated by SPAD, LAI and SPAD × LAI. All parameters except soll pH exhibited spatial correlation.Soil total N and organic matter, SPAD, LAI and SPAD × LAI were all correlated to rice yield. Kriged interpolation maps provided good indication of the spatial variability in crop yield and growth status. Spatial interpolation and correlation analysis proved that SPAD × LAI was more indicative of crop growth status than individual variables, and useful for implementing growth season and topdressing as needed.