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2.
J Morphol ; 260(1): 57-64, 2004 Apr.
Article in English | MEDLINE | ID: mdl-15052596

ABSTRACT

Nineteen measurements were made on 136 skulls belonging to seven mustelid species: Meles meles (Eurasian badger), Mustela nivalis, (weasel), Mustela erminea (stoat), Mustela putorius (polecat), Lutra lutra (otter), Mustela furo (ferret), and Mustela vison (American mink), and polecat-ferret hybrids. To investigate shape, size-related effects were eliminated by dividing all measurements by their geometric means. Canonical variate analysis was used to reveal major interspecies distinctions. Excluding the ferrets and polecat-ferrets from the analysis, only 3.2% of the skulls misclassified (one mink, one weasel, and two stoats). Three groups separated on the first canonical axis: 1) badgers, 2) polecats, mink, and otters, and 3) stoats and weasels. The important variables were width of zygomatic arch and height of sagittal crest opposed to the postorbital distance, condylobasal length, and basilar length. Otters separated out on the second canonical axis; the most important variables were postorbital breadth and width of the postorbital constriction opposed to the basioccipital width. There was reasonable separation of polecats from mink on a combination of the second and third canonical axes. On the latter the most important variables were postorbital breadth opposed to postorbital distance. Addition of the ferret data showed that they lay closest to, and overlapped with, the polecats. The stoat and weasel data alone gave complete separation, with height of sagittal crest and width of zygomatic arch opposed to basioccipital width. However, using size-in data the best separation was the relationship between postorbital breadth and either basioccipital width or postorbital distance. Sexual dimorphism was demonstrated in the skulls of badgers but was shown to be relatively insignificant when compared to the interspecific differences.


Subject(s)
Mustelidae/anatomy & histology , Skull/anatomy & histology , Anatomy, Comparative , Animals , Crosses, Genetic , Female , Ferrets/anatomy & histology , Ferrets/physiology , Genetic Variation/physiology , Male , Mink/anatomy & histology , Mink/physiology , Mustelidae/physiology , Occipital Bone/anatomy & histology , Occipital Bone/physiology , Sex Characteristics , Skull/physiology , United Kingdom , Zygoma/anatomy & histology , Zygoma/physiology
3.
Heredity (Edinb) ; 85 ( Pt 1): 62-74, 2000 Jul.
Article in English | MEDLINE | ID: mdl-10971692

ABSTRACT

Three sibling species of rough periwinkles are currently recognized: Littorina arcana, L. compressa and L. saxatilis. Certain forms of L. saxatilis are also argued by some to deserve species status, such as the barnacle-dwelling 'L. neglecta' and the lagoonal 'L. tenebrosa'. Relationships between these taxa, and between and within representative populations, are investigated using sequence analysis and restriction fragment length polymorphism of a mitochondrial DNA fragment spanning the cytochrome oxidase I and cytochrome oxidase II gene boundary. These data show that there is some sharing of haplotypes between species, with L. arcana haplotypes paraphyletic with respect to L. saxatilis haplotypes, and L. compressa haplotypes paraphyletic to both L. arcana and L. saxatilis haplotypes. Such sharing of mtDNA haplotypes could be a consequence of either persistent hybridization or episodes of hybridization, or incomplete lineage sorting of ancestral polymorphisms. On the balance of evidence it is suggested that the latter, rather than hybridization events, is the more likely causal agent of the observed distribution. Intraspecific variation is extensive and it is suggested that the patterns of intraspecific polymorphism are explainable by a combination of historical factors (the impact of the Pleistocene ice-age) and contemporary restrictions to gene flow. It is argued that Littorina haplotypes evolved in at least two separate glacial refugia and became scattered by the subsequent range expansion around most of the coastline. Recent factors such as restricted gene flow and bottlenecks would then be capable of affecting the haplotype distribution, resulting in the pattern observed.


Subject(s)
DNA, Mitochondrial , Electron Transport Complex IV/genetics , Haplotypes , Mollusca/genetics , Animals , Base Sequence , DNA Restriction Enzymes/metabolism , Evolution, Molecular , Genetic Variation , Molecular Sequence Data , Mollusca/enzymology , Phylogeny , Polymerase Chain Reaction , Polymorphism, Restriction Fragment Length , Sequence Analysis, DNA , Sequence Homology, Nucleic Acid
4.
Hereditas ; 133(1): 9-18, 2000.
Article in English | MEDLINE | ID: mdl-11206859

ABSTRACT

Primers for amplification of four novel, unlinked nuclear DNA loci, the first reported for the rough periwinkles of the genus Littorina, are described. Patterns of restriction site polymorphism for these loci are detailed within the rough periwinkles. RFLPs are not found to be diagnostic for any of the currently accepted species within this group, nor for any of the contentious subspecies, or forms, whose taxonomic status is uncertain. However, there are important differences in allele frequencies between these taxa and certain of these mirror differences detected in a previous study of the mitochondrial DNA. These allele frequency data are used to construct a phylogeny in which groupings of the three recognised species are obvious when either Nei's genetic distances or Reynold's distances are clustered. Contentious forms (L. neglecta, L. saxatilis 'b' and L. tenebrosa) do not cluster as distinct taxa, although populations of L. neglecta have important allele frequency differences from L. saxatilis. These four loci have confirmed the consensus view of Littorina phylogeny and provided important information on population structure-however four loci is insufficient for reaching definitive conclusions. Since analysis of nuclear DNA polymorphisms such as these is invaluable for analysis of phylogeny, population structure and phylogeography, identification of additional loci is considered imperative.


Subject(s)
DNA/analysis , Gene Frequency , Phylogeny , Snails/genetics , Animals , DNA Primers/chemistry , Linkage Disequilibrium , Phenotype , Polymerase Chain Reaction , Polymorphism, Restriction Fragment Length , Population Density , Sequence Deletion/genetics , Snails/physiology
5.
J Mol Evol ; 48(3): 348-59, 1999 Mar.
Article in English | MEDLINE | ID: mdl-10093225

ABSTRACT

A 8022 base pair fragment from the mitochondrial DNA of the prosobranch gastropod Littorina saxatilis has been sequenced and shown to contain the complete genes for 12 transfer RNAs and five protein genes (CoII, ATPase 6, ATPase 8, ND1, ND6), two partial protein genes (CoI and cyt b), and two ribosomal RNAs (small and large subunits). The order of these constituent genes differs from those of other molluscan mitochondrial gene arrangements. Only a single rearrangement involving a block of protein coding genes and three tRNA translocations are necessary to produce identical gene orders between L. saxatilis and K. tunicata. However, only one gene boundary is shared between the L. saxatilis gene order and that of the pulmonate gastropod Cepaea nemoralis. This extends the observation that there is little conservation of mitochrondrial gene order amongst the Mollusca and suggests that radical mitochondrial DNA gene rearrangement has occurred on the branch leading to the pulmonates.


Subject(s)
DNA, Mitochondrial/genetics , Genome , Mollusca/genetics , Phylogeny , Amino Acid Sequence , Animals , Base Sequence , DNA Primers , Evolution, Molecular , Genetic Code , Molecular Sequence Data , Mollusca/classification , Nucleic Acid Conformation , RNA, Ribosomal/chemistry , RNA, Ribosomal/genetics , RNA, Transfer/chemistry , RNA, Transfer/genetics
6.
J Chir (Paris) ; 134(9-10): 447-8, 1997.
Article in French | MEDLINE | ID: mdl-9682766

ABSTRACT

At discovery of diabetes mellitus, complementary explorations revealed a superinfection of a giant Meckel's diverticulum. We present this clinical situation in one case and suggest possible nosologies. The epidemiology and clinical approach to Meckel's diverticulum are discussed.


Subject(s)
Diabetes Complications , Meckel Diverticulum/diagnosis , Adult , Diabetes Mellitus/diagnosis , Diabetes Mellitus/therapy , Humans , Male , Meckel Diverticulum/complications , Meckel Diverticulum/surgery , Tomography, X-Ray Computed
16.
Tissue Cell ; 3(4): 623-36, 1971.
Article in English | MEDLINE | ID: mdl-18631577

ABSTRACT

An ultrastructural study of the earthworm body wall has revealed three types of sensory cells. Two, the multiciliate and uniciliate sensory cells, are found only in the discrete sense organs and their cilia pass vertically through the cuticle. The third type-isolated multiciliate sensory cells-are scattered throughout the epidermis and never grouped together. However, their cilia do not pass through the cuticle, but run horizontally over the outer surface of the epidermal cells. The structure of the sensory cells is described and compared with that of ordinary epidermal cells and the supporting cells found in the sense organs. Their possible physiological roles are discussed.

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