La Charte des droits et libertés de la personne et la tenue vestimentaire à l'école publique

Les auteurs s'attachent, dans le présent article, à établir l'influence possible de la Charte des droits et libertés de la personne sur les règles de tenue vestimentaire à l'école publique. Dans la première partie de l'étude, les auteurs présentent les pouvoirs normatifs des autorités scolaires en matière vestimentaire, ainsi que les droits et libertés susceptibles d'être mis en cause par ces pouvoirs. Ils font aussi valoir que le statut confessionnel d'un établissement d'enseignement ne fait nullement obstacle à l'application de la Charte aux normes vestimentaires. Dans la deuxième partie, les auteurs expliquent de quelle manière ces normes peuvent méconnaître les libertés d'expression, de conscience et de religion, ainsi que les droits à l'égalité protégés par la Charte. Ils proposent également un cadre d'évaluation des restrictions pouvant être apportées à ces droits et libertés aux termes de l'article 9.1 de la Charte, ou encore en vertu des défenses précisément applicables en matière de discrimination. Les auteurs concluent notamment que si l'école pourra vraisemblablement censurer les pratiques vestimentaires contraires aux valeurs de tolérance et de non-violence, elle ne pourra normalement pas justifier une prohibition pure et simple de signes religieux dont, entre autres, le foulard islamique.This paper assesses the possible impact of the Charter of Human Rights and Freedoms on student dress codes in public schools. In the first part of the article, the authors review the regulatory powers of school authorities with regard to student dress and argue that such powers are fully subject to the Charter, even in the case of confessional schools. It is then showed, in the second part of the article, how specific rights and freedoms may be infringed by dress codes. These include freedom of speech, freedom of conscience and religion, and equality rights. But it will also be explained that schools may, pursuant to both section 9.1 of the Charter and specific defences, be justified in imposing limits on rights and freedoms. The authors conclude, for example, that the need to foster nonviolence and tolerance in schools may well provide justification for prohibiting certain garments. However, they take the view that religious symbols, including the hidjab, should normally be allowed

An unexpectedly large and loosely packed mitochondrial genome in the charophycean green alga Chlorokybus atmophyticus

<p>Abstract</p> <p>Background</p> <p>The Streptophyta comprises all land plants and six groups of charophycean green algae. The scaly biflagellate <it>Mesostigma viride </it>(Mesostigmatales) and the sarcinoid <it>Chlorokybus atmophyticus </it>(Chlorokybales) represent the earliest diverging lineages of this phylum. In trees based on chloroplast genome data, these two charophycean green algae are nested in the same clade. To validate this relationship and gain insight into the ancestral state of the mitochondrial genome in the Charophyceae, we sequenced the mitochondrial DNA (mtDNA) of <it>Chlorokybus </it>and compared this genome sequence with those of three other charophycean green algae and the bryophytes <it>Marchantia polymorpha </it>and <it>Physcomitrella patens</it>.</p> <p>Results</p> <p>The <it>Chlorokybus </it>genome differs radically from its 42,424-bp <it>Mesostigma </it>counterpart in size, gene order, intron content and density of repeated elements. At 201,763-bp, it is the largest mtDNA yet reported for a green alga. The 70 conserved genes represent 41.4% of the genome sequence and include <it>nad10 </it>and <it>trnL</it>(gag), two genes reported for the first time in a streptophyte mtDNA. At the gene order level, the <it>Chlorokybus </it>genome shares with its <it>Chara</it>, <it>Chaetosphaeridium </it>and bryophyte homologues eight to ten gene clusters including about 20 genes. Notably, some of these clusters exhibit gene linkages not previously found outside the Streptophyta, suggesting that they originated early during streptophyte evolution. In addition to six group I and 14 group II introns, short repeated sequences accounting for 7.5% of the genome were identified. Mitochondrial trees were unable to resolve the correct position of <it>Mesostigma</it>, due to analytical problems arising from accelerated sequence evolution in this lineage.</p> <p>Conclusion</p> <p>The <it>Chlorokybus </it>and <it>Mesostigma </it>mtDNAs exemplify the marked fluidity of the mitochondrial genome in charophycean green algae. The notion that the mitochondrial genome was constrained to remain compact during charophycean evolution is no longer tenable. Our data raise the possibility that the emergence of land plants was not associated with a substantial gain of intergenic sequences by the mitochondrial genome.</p

The complete chloroplast DNA sequences of the charophycean green algae Staurastrum and Zygnema reveal that the chloroplast genome underwent extensive changes during the evolution of the Zygnematales

BACKGROUND: The Streptophyta comprise all land plants and six monophyletic groups of charophycean green algae. Phylogenetic analyses of four genes from three cellular compartments support the following branching order for these algal lineages: Mesostigmatales, Chlorokybales, Klebsormidiales, Zygnematales, Coleochaetales and Charales, with the last lineage being sister to land plants. Comparative analyses of the Mesostigma viride (Mesostigmatales) and land plant chloroplast genome sequences revealed that this genome experienced many gene losses, intron insertions and gene rearrangements during the evolution of charophyceans. On the other hand, the chloroplast genome of Chaetosphaeridium globosum (Coleochaetales) is highly similar to its land plant counterparts in terms of gene content, intron composition and gene order, indicating that most of the features characteristic of land plant chloroplast DNA (cpDNA) were acquired from charophycean green algae. To gain further insight into when the highly conservative pattern displayed by land plant cpDNAs originated in the Streptophyta, we have determined the cpDNA sequences of the distantly related zygnematalean algae Staurastrum punctulatum and Zygnema circumcarinatum. RESULTS: The 157,089 bp Staurastrum and 165,372 bp Zygnema cpDNAs encode 121 and 125 genes, respectively. Although both cpDNAs lack an rRNA-encoding inverted repeat (IR), they are substantially larger than Chaetosphaeridium and land plant cpDNAs. This increased size is explained by the expansion of intergenic spacers and introns. The Staurastrum and Zygnema genomes differ extensively from one another and from their streptophyte counterparts at the level of gene order, with the Staurastrum genome more closely resembling its land plant counterparts than does Zygnema cpDNA. Many intergenic regions in Zygnema cpDNA harbor tandem repeats. The introns in both Staurastrum (8 introns) and Zygnema (13 introns) cpDNAs represent subsets of those found in land plant cpDNAs. They represent 16 distinct insertion sites, only five of which are shared by the two zygnematalean genomes. Three of these insertions sites have not been identified in Chaetosphaeridium cpDNA. CONCLUSION: The chloroplast genome experienced substantial changes in overall structure, gene order, and intron content during the evolution of the Zygnematales. Most of the features considered earlier as typical of land plant cpDNAs probably originated before the emergence of the Zygnematales and Coleochaetales

Chloroplast DNA sequence of the green alga <it>Oedogonium cardiacum </it>(Chlorophyceae): Unique genome architecture, derived characters shared with the Chaetophorales and novel genes acquired through horizontal transfer

<p>Abstract</p> <p>Background</p> <p>To gain insight into the branching order of the five main lineages currently recognized in the green algal class Chlorophyceae and to expand our understanding of chloroplast genome evolution, we have undertaken the sequencing of chloroplast DNA (cpDNA) from representative taxa. The complete cpDNA sequences previously reported for <it>Chlamydomonas </it>(Chlamydomonadales), <it>Scenedesmus </it>(Sphaeropleales), and <it>Stigeoclonium </it>(Chaetophorales) revealed tremendous variability in their architecture, the retention of only few ancestral gene clusters, and derived clusters shared by <it>Chlamydomonas </it>and <it>Scenedesmus</it>. Unexpectedly, our recent phylogenies inferred from these cpDNAs and the partial sequences of three other chlorophycean cpDNAs disclosed two major clades, one uniting the Chlamydomonadales and Sphaeropleales (CS clade) and the other uniting the Oedogoniales, Chaetophorales and Chaetopeltidales (OCC clade). Although molecular signatures provided strong support for this dichotomy and for the branching of the Oedogoniales as the earliest-diverging lineage of the OCC clade, more data are required to validate these phylogenies. We describe here the complete cpDNA sequence of <it>Oedogonium cardiacum </it>(Oedogoniales).</p> <p>Results</p> <p>Like its three chlorophycean homologues, the 196,547-bp <it>Oedogonium </it>chloroplast genome displays a distinctive architecture. This genome is one of the most compact among photosynthetic chlorophytes. It has an atypical quadripartite structure, is intron-rich (17 group I and 4 group II introns), and displays 99 different conserved genes and four long open reading frames (ORFs), three of which are clustered in the spacious inverted repeat of 35,493 bp. Intriguingly, two of these ORFs (<it>int </it>and <it>dpoB</it>) revealed high similarities to genes not usually found in cpDNA. At the gene content and gene order levels, the <it>Oedogonium </it>genome most closely resembles its <it>Stigeoclonium </it>counterpart. Characters shared by these chlorophyceans but missing in members of the CS clade include the retention of <it>psaM</it>, <it>rpl32 </it>and <it>trnL</it>(caa), the loss of <it>petA</it>, the disruption of three ancestral clusters and the presence of five derived gene clusters.</p> <p>Conclusion</p> <p>The <it>Oedogonium </it>chloroplast genome disclosed additional characters that bolster the evidence for a close alliance between the Oedogoniales and Chaetophorales. Our unprecedented finding of <it>int </it>and <it>dpoB </it>in this cpDNA provides a clear example that novel genes were acquired by the chloroplast genome through horizontal transfers, possibly from a mitochondrial genome donor.</p

The complete chloroplast genome sequence of the chlorophycean green alga Scenedesmus obliquus reveals a compact gene organization and a biased distribution of genes on the two DNA strands

BACKGROUND: The phylum Chlorophyta contains the majority of the green algae and is divided into four classes. While the basal position of the Prasinophyceae is well established, the divergence order of the Ulvophyceae, Trebouxiophyceae and Chlorophyceae (UTC) remains uncertain. The five complete chloroplast DNA (cpDNA) sequences currently available for representatives of these classes display considerable variability in overall structure, gene content, gene density, intron content and gene order. Among these genomes, that of the chlorophycean green alga Chlamydomonas reinhardtii has retained the least ancestral features. The two single-copy regions, which are separated from one another by the large inverted repeat (IR), have similar sizes, rather than unequal sizes, and differ radically in both gene contents and gene organizations relative to the single-copy regions of prasinophyte and ulvophyte cpDNAs. To gain insights into the various changes that underwent the chloroplast genome during the evolution of chlorophycean green algae, we have sequenced the cpDNA of Scenedesmus obliquus, a member of a distinct chlorophycean lineage. RESULTS: The 161,452 bp IR-containing genome of Scenedesmus features single-copy regions of similar sizes, encodes 96 genes, i.e. only two additional genes (infA and rpl12) relative to its Chlamydomonas homologue and contains seven group I and two group II introns. It is clearly more compact than the four UTC algal cpDNAs that have been examined so far, displays the lowest proportion of short repeats among these algae and shows a stronger bias in clustering of genes on the same DNA strand compared to Chlamydomonas cpDNA. Like the latter genome, Scenedesmus cpDNA displays only a few ancestral gene clusters. The two chlorophycean genomes share 11 gene clusters that are not found in previously sequenced trebouxiophyte and ulvophyte cpDNAs as well as a few genes that have an unusual structure; however, their single-copy regions differ considerably in gene content. CONCLUSION: Our results underscore the remarkable plasticity of the chlorophycean chloroplast genome. Owing to this plasticity, only a sketchy portrait could be drawn for the chloroplast genome of the last common ancestor of Scenedesmus and Chlamydomonas

Distinctive architecture of the chloroplast genome in the chlorodendrophycean green algae Scherffelia dubia and Tetraselmis sp. CCMP 881

The Chlorodendrophyceae is a small class of green algae belonging to the core Chlorophyta, an assemblage that also comprises the Pedinophyceae, Trebouxiophyceae, Ulvophyceae and Chlorophyceae. Here we describe for the first time the chloroplast genomes of chlorodendrophycean algae (Scherffelia dubia, 137,161 bp; Tetraselmis sp. CCMP 881, 100,264 bp). Characterized by a very small single-copy (SSC) region devoid of any gene and an unusually large inverted repeat (IR), the quadripartite structures of the Scherffelia and Tetraselmis genomes are unique among all core chlorophytes examined thus far. The lack of genes in the SSC region is offset by the rich and atypical gene complement of the IR, which includes genes from the SSC and large single-copy regions of prasinophyte and streptophyte chloroplast genomes having retained an ancestral quadripartite structure. Remarkably, seven of the atypical IR-encoded genes have also been observed in the IRs of pedinophycean and trebouxiophycean chloroplast genomes, suggesting that they were already present in the IR of the common ancestor of all core chlorophytes. Considering that the relationships among the main lineages of the core Chlorophyta are still unresolved, we evaluated the impact of including the Chlorodendrophyceae in chloroplast phylogenomic analyses. The trees we inferred using data sets of 79 and 108 genes from 71 chlorophytes indicate that the Chlorodendrophyceae is a deep-diverging lineage of the core Chlorophyta, although the placement of this class relative to the Pedinophyceae remains ambiguous. Interestingly, some of our phylogenomic trees together with our comparative analysis of gene order data support the monophyly of the Trebouxiophyceae, thus offering further evidence that the previously observed affiliation between the Chlorellales and Pedinophyceae is the result of systematic errors in phylogenetic reconstruction

The chloroplast genome sequence of the green alga Leptosira terrestris: multiple losses of the inverted repeat and extensive genome rearrangements within the Trebouxiophyceae

<p>Abstract</p> <p>Background</p> <p>In the Chlorophyta – the green algal phylum comprising the classes Prasinophyceae, Ulvophyceae, Trebouxiophyceae and Chlorophyceae – the chloroplast genome displays a highly variable architecture. While chlorophycean chloroplast DNAs (cpDNAs) deviate considerably from the ancestral pattern described for the prasinophyte <it>Nephroselmis olivacea</it>, the degree of remodelling sustained by the two ulvophyte cpDNAs completely sequenced to date is intermediate relative to those observed for chlorophycean and trebouxiophyte cpDNAs. <it>Chlorella vulgaris </it>(Chlorellales) is currently the only photosynthetic trebouxiophyte whose complete cpDNA sequence has been reported. To gain insights into the evolutionary trends of the chloroplast genome in the Trebouxiophyceae, we sequenced cpDNA from the filamentous alga <it>Leptosira terrestris </it>(Ctenocladales).</p> <p>Results</p> <p>The 195,081-bp <it>Leptosira </it>chloroplast genome resembles the 150,613-bp <it>Chlorella </it>genome in lacking a large inverted repeat (IR) but differs greatly in gene order. Six of the conserved genes present in <it>Chlorella </it>cpDNA are missing from the <it>Leptosira </it>gene repertoire. The 106 conserved genes, four introns and 11 free standing open reading frames (ORFs) account for 48.3% of the genome sequence. This is the lowest gene density yet observed among chlorophyte cpDNAs. Contrary to the situation in <it>Chlorella </it>but similar to that in the chlorophycean <it>Scenedesmus obliquus</it>, the gene distribution is highly biased over the two DNA strands in <it>Leptosira</it>. Nine genes, compared to only three in <it>Chlorella</it>, have significantly expanded coding regions relative to their homologues in ancestral-type green algal cpDNAs. As observed in chlorophycean genomes, the <it>rpoB </it>gene is fragmented into two ORFs. Short repeats account for 5.1% of the <it>Leptosira </it>genome sequence and are present mainly in intergenic regions.</p> <p>Conclusion</p> <p>Our results highlight the great plasticity of the chloroplast genome in the Trebouxiophyceae and indicate that the IR was lost on at least two separate occasions. The intriguing similarities of the derived features exhibited by <it>Leptosira </it>cpDNA and its chlorophycean counterparts suggest that the same evolutionary forces shaped the IR-lacking chloroplast genomes in these two algal lineages.</p

Reliable microsatellite genotyping of the Eurasian badger (Meles meles) using faecal DNA

The potential link between badgers and bovine tuberculosis has made it vital to develop accurate techniques to census badgers. Here we investigate the potential of using genetic profiles obtained from faecal DNA as a basis for population size estimation. After trialling several methods we obtained a high amplification success rate (89%) by storing faeces in 70% ethanol and using the guanidine thiocyanate/silica method for extraction. Using 70% ethanol as a storage agent had the advantage of it being an antiseptic. In order to obtain reliable genotypes with fewer amplification reactions than the standard multiple-tubes approach, we devised a comparative approach in which genetic profiles were compared and replication directed at similar, but not identical, genotypes. This modified method achieved a reduction in polymerase chain reactions comparable with the maximumlikelihood model when just using reliability criteria, and was slightly better when using reliability criteria with the additional proviso that alleles must be observed twice to be considered reliable. Our comparative approach would be best suited for studies that include multiple faeces from each individual. We utilized our approach in a well-studied population of badgers from which individuals had been sampled and reliable genotypes obtained. In a study of 53 faeces sampled from three social groups over 10 days, we found that direct enumeration could not be used to estimate population size, but that the application of mark–recapture models has the potential to provide more accurate results

Automated mapping of social networks in wild birds

Growing interest in the structure and dynamics of animal social networks has stimulated major advances [1], [2] and [3], but recording reliable association data for wild populations has remained challenging. While animal-borne ‘proximity’ tags have been available for some time [4], earlier devices were comparatively heavy, had limited detection ranges and/or necessitated recovery for data retrieval. We have developed wireless digital transceiver technology (‘Encounternet') that enables automated mapping of social networks in wild birds, yielding datasets of unprecedented size, quality and spatio-temporal resolution. Miniature, animal-borne tags record the proximity and duration of bird encounters, and periodically transfer logs to a grid of fixed receiver stations, from which datasets can be downloaded remotely for real-time analysis. We used our system to chart social associations in New Caledonian crows Corvus moneduloides [5] and [6]. Analysis of ca. 28,000 encounter logs for 34 crows over a 7-day period reveals a substantial degree of close-range association between non-family birds, demonstrating the potential for horizontal and oblique information exchange