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this paper we investigate the evolution and determinants of host specificity in Lamellodiscus species. There are five main lines of inquiry: (1) Determining whether specificity is constrained by the phylogeny of the parasites. In other words, whether parasites with the same level of specificity are more closely related to each other than they are to other congeneric species. If so, support is given to the Table 1. Data on Lamellodiscus species (including Furnestinia echeneis): parasite maximum size (in mm), host species, host maximum size (in mm), and specificity (classes). The main hosts for generalist parasites are in boldface Parasite species Parasite size Host Host size Specificity F. echeneis 1100 Sparus aurata 700 1 L. baeri 1000 Pagrus pagrus 750 1 L. bidens 1020 Diplodus puntazzo 600 1 L. coronatus 1000 Diplodus annularis 240 3 Diplodus cervinus 550 L. drummondi 420 Pagellus acarne 360 1 L. elegans 520 Diplodus annularis 240 4 Diplodus sargus 400 Spondyliosoma cantharus 600 L. ergensi 600 Diplodus annularis 240 3 Diplodus sargus 400 L. erythrini 580 Pagellus erythrinus 600 1 L. fraternus 430 Diplodus annularis 240 2 L. furcosus 670 Diplodus annularis 240 3 L. gracilis 700 Diplodus annularis 240 3 L. hilii 1050 Diplodus puntazzo 600 1 L. ignoratus 640 Diplodus annularis 240 4 Diplodus sargus 400 Lithognathus mormyrus 550 Sarpa salpa 460 L. impervius 550 Diplodus puntazzo 600 1 L. knoepffleri 730 Spondyliosoma cantharus 600 4 Spicara maena 250 Spicara smaris 200 L. mirandus 800 Diplodus sargus 400 1 L. mormyri 480 Lithognathus mormyrus 600 1 L. parisi 550 Sarpa salpa 460 1 L. verberis 500 Lithognathus mormyrus 600 1 L. virgula 470 Pagellus acarne 360 2 Pagellus bogaraveo 700 434 Y. DESDEVISES ET AL

In this paper, we present a new shape analysis approachusing the well-known wavelet transform andexploring shape representation by landmarks. First, we describe the approach adopted to represent the landmarks data as parametric sigamet Then, we show the relation of the derivatives of Gaussian wavelet transform applied to the sigWGGWquHxWGxxugxug properties of the shape that it represents. We present experimental resultsusing real data to show how it is possible to characterize shapes throug multiscale and differential sigerentialuxfiBz techniques in order to relate morphologuHx variables with phylogq[uHx siglog environmental factors and sexual dimorphism. The geu of this research is to develop an effective wavelet transform-based method to represent and classify multiple classes of shapesgape by landmarks.

According to the ‘masking hypothesis’, diploids gain an immediate fitness advantage over haploids because diploids, with two copies of every gene, are better able to survive the effects of deleterious recessive mutations. Masking in diploids is, however, a double-edged sword: it allows mutations to persist over time. In contrast, deleterious mutations are revealed in haploid individuals and are more rapidly eliminated by selection, creating genetic associations that are favourable to haploidy. We model various mating schemes and show that assortative mating, selfing, and apomixis maintain the genetic associations that favour haploidy. These results suggest that a correlation should exist between mating system and ploidy level, with outcrossing favouring diploid life cycles and inbreeding or asexual reproduction favouring haploid life cycles. This prediction can be tested in groups, such as the Chlorophyta, with extensive variation both in life cycle and in reproductive system. Confirming or rejecting this prediction in natural populations would constitute the first empirical test of the masking hypothesis as a force shaping the evolution of life cycles.

Research article Global and regional brain metabolic scaling and its functional consequences

m e t h o d o l o g y

Mechanisms underlying the dramatic patterns of genome size variation across the tree of life remain mysterious. Effective population size (Ne) has been proposed as a major driver of genome size: selection is expected to efficiently weed out deleterious mutations increasing genome size in lineages with large (but not small) Ne. Strong support for this model was claimed from a comparative analysis of Neu and genome size for <30 phylogenetically diverse species ranging from bacteria to vertebrates, but analyses at that scale have so far failed to account for phylogenetic nonindependence of species. In our reanalysis, accounting for phylogenetic history substantially altered the perceived strength of the relationship between Neu and genomic attributes: there were no statistically significant associations between Neu and gene number, intron size, intron number, the half-life of gene duplicates, transposon number, transposons as a fraction of the genome, or overall genome size. We conclude that current datasets do not support the hypothesis of a mechanistic connection between Ne and these genomic attributes, and we suggest that further progress requires larger datasets, phylogenetic comparative methods, more robust estimators of genetic drift, and a multivariate approach that accounts for correlations between putative explanatory variables.

When conducting inter-species regression analyses, the phylogenetic relationships between the individual species need to be taken into account. In this paper, a procedure for conducting such analyses is discussed, which only requires the use of a measure of relationship between pairs of species, rather than a complete phylogeny, and which at the same time assesses the importance to be attached to the relationships with regard to the conclusions reached. The procedure is applied to data from Minder et al. (2005), relating testis size to mean hind tibia length, duct length and spermathecal area in 15 species of Scathophagidae (Diptera). We show that considering the phylogenetic structure significantly improves the fit of the model to the data. We find a robust relationship between testis size and spermathecal area but could not support one between testis size and spermathecal duct length. Keywords: likelihood based inference, Ornstein-Uhlenbeck process, phylogenetic relationship. 2 1

Taking advantage of the massive genome sequencing effort made on thermophilic prokaryotes, thermal adaptation has been extensively studied by analysing amino acid replacements and codon usage in these unicellular organisms. In most cases, adaptation to thermophily is associated with greater residue hydrophobicity and more charged residues. Both of these characteristics are positively correlated with the optimal growth temperature of prokaryotes. In contrast, little information has been collected on the molecular ‘adaptive ’ strategy of thermophilic eukaryotes. The Pompeii worm A. pompejana, whose transcriptome has recently been sequenced, is currently considered as the most thermotolerant eukaryote on Earth, withstanding the greatest thermal and chemical ranges known. We investigated the amino-acid composition bias of ribosomal proteins in the Pompeii worm when compared to other lophotrochozoans and checked for putative adaptive changes during the course of evolution using codon-based Maximum likelihood analyses. We then provided a comparative analysis of codon usage and amino-acid replacements from a greater set of orthologous genes between the Pompeii worm and Paralvinella grasslei, one of its closest relatives living in a much cooler habitat. Analyses reveal that both species display the same high GC-biased codon usage and amino-acid patterns favoring both positivelycharged residues and protein hydrophobicity. These patterns may be indicative of an ancestral adaptation to the deep sea and/or thermophily. In addition, the Pompeii worm displays a set of amino-acid change patterns that may explain its greater