jeanflop/post-ocr-correction huggingface dataset:
Waheedud DIN, Bruno DAVID, Bernard LAURIN, Jean CHALINE, Masashi HARADA and François CATZEFIS Abstract Molecular data derived from DNA/DNA hybridization experiments, and morphological distances based upon the Homologous Landmarks distance approach are presented for establishing the evolutionary systematics of some voles Clethrionomyini (Arvicolinae, Rodentia). A comparison of the phenetic trees derived from both approaches indicates similarities and differences in the branching pattern depicting the relationships between the different taxa. Étude comparative des Clethrionomyini (Arvicolidae, Rodentia) par l'hybridation de l'ADN et la morphologie; Résumé Les données moleculaires tirées de l'hybridation ADN/ADN sont comparées aux distances phénétiques obtenues par la méthode des
sont comparées aux distances phénétiques obtenues par la méthode des points homologues chez les campagnols (Arvicolinae, Rodentia) de la tribu des Clethrionomyini. Elles montrent qu'il y a des ressemblances et des divergences qui permettent de discuter les relations des diverses espèces. Version française abrégée — Les campagnols et les lemmings constituent le groupe des Arvicolinae, l'une des 15 sous-familles actuelles des Muridae sensu lato (Carleton and Musser, 1984). Les Clethrionomyini, une des nombreuses tribus des Arvicolinae, renferment les genres Clethrionomys (5 espèces paléarctiques actuelles) et Eothenomys (11 espèces actuelles). Les deux genres diffèrent par la persistance des racines dentaires chez
deux genres diffèrent par la persistance des racines dentaires chez Clethrionomys et l'acquisition de la croissance dentaire continue (caractère dérivé) chez Eothenomys (Honacki et al., 1982). En outre, les morphologies occlusales des deux genres sont différentes, caractérisées par des triangles alternés chez Clethrionomys et des rhombes dentaires chez Eothenomys. Les relations de parenté entre les deux genres ont fait l'objet de recherches paléontologiques (Chaline, 1987; Zheng and Li, 1990; Chow and Yuanking, 1992; Kawamura, 1988), biochimiques (Graf, 1982) et morphologiques (Chaline and Graf, 1988; Stein, 1987; Bauchau et Chaline, 1987), mais, malgré cela, leur systématique est encore confuse (Corbet, 1978)
mais, malgré cela, leur systématique est encore confuse (Corbet, 1978) en raison de convergences morphologiques probables. Le but de ce travail est de comparer les informations évolutives tirées de deux types de distances : distances moléculaires évaluées par l'hybridation ADN/ADN et distances morphologiques établies à partir de la méthode des points homologues (Sneath, 1967; David et Laurin, 1989; Laurin and David, 1991; Rohlf, 1990; Rohlf and Bookstein, 1990; David et Laurin, 1992; Zelditch et al., 1992) et de les confronter aux données paléontologiques (Chaline, 1987; Zheng and Li, 1990; Chow, 1992; Kawamura, 1988). HYBRIDATION ADN/ADN. — Les expériences moléculaires (tableau
1992; Kawamura, 1988). HYBRIDATION ADN/ADN. — Les expériences moléculaires (tableau I) ont été effectuées selon les techniques classiques (Catzeflis, 1990, 1991; Sibley and Alquist, 1981; Werman et al., 1990; Catzeflis et al., 1987, 1989; She et al., 1989). Les données brutes ont été transformées en courbes modales qui permettent le calcul des valeurs en delta-Mode (Catzeflis, 1990; She et al., 1989; Sheldon and Bledsoe, 1989; Champion et al., 1974; fig. 1). Les valeurs du delta-Mode (tableau II) arrangées en une matrice de distances ADN/ADN (tableau III) permettent de reconstituer un arbre phylogénétique partiel (fig. 2) dont la racine a été
arbre phylogénétique partiel (fig. 2) dont la racine a été placée à mi-chemin du groupe externe Ondatra zibethicus et sur lequel ont été replacés E. melanogaster et C. rutilus. DISTANCES MORPHOLOGIQUES. — Les crânes sont décrits par 43 points homologues (fig. 3). Ils sont comparés deux à deux en utilisant une méthode d'ajustement par les moindres carrés (LSTRA; Sneath, 1967; David et Laurin, 1989; Laurin and David, 1991; Rohlf, 1990; Rohlf and Bookstein, 1990) proposée par le programme Procrustes (David et Laurin, 1992). La méthode utilisée exprime les différences entre les formes en terme de distances morphologiques (phénétiques). Les distances
les formes en terme de distances morphologiques (phénétiques). Les distances qui correspondent aux sommes des vecteurs ( £ A) joignant les points homologues des différents crânes comparés (tableau IV), sont transformées en un arbre phénétique (fig. 4) réalisé à partir de l'algorithme Fitch du programme Phylip (Felsenstein, 1990). DISCUSSION. — Les relations morphologiques déduites de l'analyse des points homologues présentent des ressemblances et des différences avec celles tirées des données moléculaires. Ondatra zibethicus, étant pris comme groupe externe, vis-à-vis des autres campagnols eurasiatiques, les deux approches confirment la proximité entre Clethrionomys et Eothenomys (Corbet, 1978; Miller, 1896). Elle montre que
Clethrionomys et Eothenomys (Corbet, 1978; Miller, 1896). Elle montre que C. glareolus et C. rutilus sont très proches, et que C. rufocanus est l'espèce la plus divergente au sein de Clethrionomys, une vue confortée par une estimation indépendante des distances génomiques par l'hybridation ADN (Guileva et al., 1990). Les divergences entre les deux approches portent sur les positions relatives de Microtus epiroticus vis-à-vis de C. rufocanus et de E. melanogaster. La morphologie suggère une certaine convergence entre C. rufocanus et M. epiroticus alors que la divergence moléculaire est plus forte. La morphologie montre aussi que Eothenomys est si proche du
La morphologie montre aussi que Eothenomys est si proche du groupe des Clethrionomys que l'on peut se demander si sa distinction générique est justifiée (le fait que dans une étude moléculaire en cours E. kageus se situe au sein du groupe Clethrionomys renforce cette idée). En ce qui concerne la paléontologie, si l'on essaie de replacer l'arbre phylogénétique tiré des hybridations ADN/ADN en utilisant l'hypothèse de l'horloge moléculaire (Marshall, 1992), à partir de la calibration fondée sur l'âge de Prosomys vers 5 Ma (Martin, 1979) on constate des distorsions dans l'âge des nœuds (fig. 2) : 2,8 au lieu de
l'âge des nœuds (fig. 2) : 2,8 au lieu de 1,8 Ma pour la séparation de E. melanogaster, 2 au lieu de 0,46 Ma pour celle de C. rufocanus. Ces distorsions peuvent être dues, soit à l'insuffisance des archives paléontologiques, soit à des variations de rythme de l'horloge moléculaire. Le fait que les formes théoriquement les plus dérivées (E. melanogaster sans racines dentaires) apparaissent avant les formes radiculées supposées primitives (C. glareolus) remet en cause les relations entre Clethrionomys et Eothenomys. The aim of this paper is to compare the evolutionary information derived from two kinds of distances: molecular genomic
evolutionary information derived from two kinds of distances: molecular genomic distances, as provided by DNA/DNA hybridization, and morphological distances, as derived from a Procrustean approach (Sneath, David and Laurin, 1989; Laurin and David, 1991; Rohlf, 1990; Rohlf and Bookstein, 1990; David and Laurin, 1992; Zelditch et al., 1992) which seems particularly well suited to describe the complexity of skull morphologies. Distances deduced from these two approaches will be then compared with data from the fossil record (Chaline, 1987; Zheng and Li, 1990; Chow, 1992; Kawamura, 1988). DNA/DNA HYBRIDIZATION EXPERIMENTS. The origin of tissue samples of rodents is given in table
origin of tissue samples of rodents is given in table I. DNA/DNA hybridization experiments were performed according to the classical procedures (Catzeflis, 1991; Sibley and Alquist, 1982; Werman et al., 1990), and are identical to those used in previous papers (Catzeflis et al., 1987, 1989; Catzeflis, 1990; She et al., 1989). The raw data (radioactive counts) were transformed into Modal curves (fig. 1), which allowed the calculations of the Mode statistics as described in (Catzeflis, 1990) and (Sheldon and Bledsoe, 1989). Delta-Mode values were transformed into estimates of percent nucleotide substitutions, and these values were calibrated against the geological time
substitutions, and these values were calibrated against the geological time provided by the fossil record (as in Catzeflis et al., 1987, 1989). Single-copy DNA samples of Clethrionomys gapperi, C. rufocanus, C. glareolus and Microtus epiroticus were radioactively labeled (tracer species) and used for hybridization experiments. Table II gives the delta-Mode values (average, and standard deviation) obtained, which make up the basis of our molecular interpretations. Complete melting curves for five different tracer/driver comparisons are illustrated in figure 1; each curve is based on the average of several duplicate hybrids, and the vertical bars at each temperature, representing the standard deviation
the vertical bars at each temperature, representing the standard deviation of the raw data, illustrate the experimental variability. The delta-Mode values of table II appear to be near-reciprocal, and their Mean Percent Deviation from Average (Champion et al., 1974) averages 4.93±2.62%. Keeping this homoplasy as such, the delta-Mode values were averaged in an incomplete matrix of DNA/DNA distances (table III), from which a phylogenetic tree was constructed by hand, assuming near-equality of rates of change (fig. 2). The root has been placed at mid-length of the segment leading to the outgroup Ondatra zibethicus (a choice made in agreement with the
outgroup Ondatra zibethicus (a choice made in agreement with the dental morphology). Every node in the tree of figure is bordered by a rectangle representing ± one standard deviation of the mean value of the hybrid comparisons involved in that node (data in table III). MORPHOLOGICAL DISTANCES. — The so-called Procrustean approaches [15, 16, 18] measure differences between morphological shapes and allow us to establish morphological (phenetic) distances. The vole skulls are described by 43 homologous landmarks (fig. 3). They are compared using a least-square fitting technique (LSTRA; Sneath, 1967; David and Laurin, 1989; Laurin and David, 1991; Rohlf, 1990;
David and Laurin, 1989; Laurin and David, 1991; Rohlf, 1990; Rohlf and Bookstein, 1990) available in the program Procrustes (David and Laurin, 1992). The shape difference between two skulls is summarized by a series of vectors, each vector joining a homologous landmark. Fig. 1. Melting curves of percent single-copy DNA eluted versus temperature, in the 62.5-95.0°C range. Each curve is based on the average (vertical bars represent standard deviation) of the radioactive counts from N hybrids. The single-copy DNA tracer (*) is Clethrionomys rufocanus. A: *C. rufocanus/C. rufocanus homologue; B: *C. rufocanus/C. rutilus; C: *C. rufocanus/C. gapperi; D: *C. rufocanus/Eothenomys
*C. rufocanus/C. rutilus; C: *C. rufocanus/C. gapperi; D: *C. rufocanus/Eothenomys melanogaster; E: *C. rufocanus/Ondatra zibethicus. Fig. 1. Courbes d'élution thermique des ADN hybrides dissociés en fonction de la température (de 62,5 à 95,0° C). Chaque courbe est basée sur la moyenne (les barres verticales représentant l'écart-type) des comptages radioactifs à N hybrides. L'ADN non répété marqué radioactivement (traceur) est celui de l'espèce Clethrionomys rufocanus. A: homologue *C. rufocanus/C. rufocanus; B: *C. rufocanus/C. rutilus; C: *C. rufocanus/C. gapperi; D: *C. rufocanus/Eothenomys melanogaster; E: *C. rufocanus/Ondatra zibethicus. Fig. 2. Phylogenetic tree derived from the data of tables II and III. Ondatra zibethicus
from the data of tables II and III. Ondatra zibethicus is an outgroup, and the root of the tree is placed at mid-length of the branch connecting O. zibethicus to the other taxa. The thin boxes bordering each node représent ± one standard deviation. Fig. 2. Arbre phylogénétique moléculaire basé sur les données des tableaux II et III. Ondatra zibethicus est le groupe externe, et la racine de l'arbre est placée à mi-chemin du segment joignant Ondatra zibethicus aux autres taxons. Les rectangles bordant chaque nœud représentent ± un écart-type. TABLE III Matrix of delta-Mode distances, averaged for reciprocity, and
TABLE III Matrix of delta-Mode distances, averaged for reciprocity, and number of hybrid comparisons. Abbreviations: C.: Clethrionomys; E.: Eothenomys; M.: Microtus, O.: Ondatra; a: no comparison available; values in parentheses are averages of C. rufocanus/Ondatra zibethicus and C. gapperi/O. zibethicus hybrids. Matrice des distances delta-Mode, moyennée dans le cas de comparaisons réciproques, et nombre d'hybrides analysés. Abbréviations: C.: Clethrionomys; E.: Eothenomys; M.: Microtus, O.: Ondatra, a: pas de comparaison disponible; les valeurs entre parenthèses sont la moyenne des hybrides C. rufocanus/O. zibethicus et C. gapperi/O. zibethicus. C. rufocanus C. glareolus C. gapperi M. epiroticus C. rufocanus C. glareolus 3.9±0.6 (4)
C. gapperi M. epiroticus C. rufocanus C. glareolus 3.9±0.6 (4) C. gapperi 4.0±0.3(6) 2.1±0.3 (7) O. zibethicus 10.0±0.3 (3) (10.4±0.3 (")) 10.8±0.2 (2) 10.5±0.1 (3) M. epiroticus 8.2±0.4 (6) 8.1±0.3 (8) 8.4±0.5 (8) (il) No comparison available; values in ( ) are averages of C. rufocanus/O. zibethicus and C. gapperi/O. zibethicus hybrids. point of the first skull to its equivalent on the second skull. Vector fields characterize differences in shape morphology fully independent of size. The sum of vector lengths (IA) is used as a morphological distance between compared specimens, and these distances are clustered into phenetic trees. The analysis
and these distances are clustered into phenetic trees. The analysis of the morphological relationships between Clethrionomys and Eothenomys is based on skull measurements of C. glareolus, C. rutilus, C. rufocanus, E. melanogaster, Microtus epiroticus and Ondatra zibethicus as an outgroup. Complete comparisons between all possible pairs of species yielded the matrix of morphological distances illustrated in table IV. These distances were transformed into a phenetic tree (fig. 4) by using the Fitch (no constancy of rates of morphological change is assumed) algorithm in the Phylip package (Felsenstein, 1990). DISCUSSION. A close evolutionary relationship among the genera of the tribe Clethrionomyini
close evolutionary relationship among the genera of the tribe Clethrionomyini has long been recognized (Miller, 1896) and recently reinforced by a qualitative myological and osteological analysis (Stein, 1987). This latter study, combining data from karyology, biochemistry, soft anatomy, and external morphology, has suggested that: (1) Eothenomys melanogaster melanogaster TABLE IV Matrix of morphometric distances between Ondatra zibethicus, Microtus epiroticus, Eothenomys melanogaster, Clethrionomys glareolus, C. rutilus and C. rufocanus. Matrice des distances morphologiques entre Ondatra zibethicus, Microtus epiroticus, Eothenomys melanogaster, Clethrionomys glareolus, C. rutilus et C. rufocanus. 12 3 4 5 E. melanogaster 2/C. glareolus 2.35 3/C. rufocanus 2.52 1.99 4/C.
E. melanogaster 2/C. glareolus 2.35 3/C. rufocanus 2.52 1.99 4/C. rutilus 2.35 2.02 2.34 5/O. zibethicus 3.54 4.19 3.38 4.13 6/M. epiroticus 2.60 2.34 1.90 2.52 3.72 in the genus Clethrionomys, the species C. glareolus, C. gapperi, and C. rutilus are closely related, whereas C. rufocanus was shown very distinctive and considered primitive within the genus; (2) Clethrionomys and Eothenomys (represented here by E. melanogaster) are sister-groups. A recent molecular study by scnDNA hybridization (Guileva et al., 1990) has indeed yielded estimates of genomic distances which clearly indicate that C. rufocanus is the most divergent species among Clethrionomys. The delta-Mode
rufocanus is the most divergent species among Clethrionomys. The delta-Mode values of table II indicate that the five species and two genera of Clethrionomyini surveyed in this study are more related to each other than to Ondatra or to Microtus. From this, it appears that the Clethrionomyini may be considered monophyletic when compared to the Microtini or Ondatrini, a view which is in agreement with other non-molecular approaches (review in Stein, 1987) suggesting that these voles might form a natural clade. The morphological relationships derived from the Homologous Landmarks approach (fig. 4) show similarities and differences with those based on
(fig. 4) show similarities and differences with those based on the molecular data (fig. 2). In both approaches Ondatra zibethicus has been taken as an outgroup to root the trees, and both approaches sustain the relationships between Clethrionomys and Eothenomys (Corbet, 1978; Miller, 1896). Both approaches also suggest that C. glareolus and C. rutilus are closely related, and that C. rufocanus is the most divergent species within Clethrionomys. This view is supported by another molecular approach using DNA/DNA hybridization (Guileva et al., 1990). Differences between the two approaches concern the relative position of Microtus epiroticus versus C. rufocanus and of
relative position of Microtus epiroticus versus C. rufocanus and of E. melanogaster versus C. rufocanus. Morphology suggests some convergence between C. rufocanus and M. epiroticus, whereas the molecular data clearly have M. epiroticus as an outgroup of the Clethrionomyini. The morphological distances also indicates that Eothenomys belongs to the clade Clethrionomys, and this casts some doubt on the validity of the genus Eothenomys (unpublished additional molecular data indeed indicate that E. kageus clusters within the genus Clethrionomys). For laboratory help, we thank Gérard Assié, Gilbert Pistre, and Anne Lagriffoul; this study would not have been feasible were it not for
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