Genetic and environmental components of phenotypic variation in immune response and body size of a colonial bird, Delichon urbica (the house martin).

Directional selection for parasite resistance is often intense in highly social host species. Using a partial cross-fostering experiment we studied environmental and genetic variation in immune response and morphology in a highly colonial bird species, the house martin (Delichon urbica). We manipulated intensity of infestation of house martin nests by the haematophagous parasitic house martin bug Oeciacus hirundinis either by spraying nests with a weak pesticide or by inoculating them with 50 bugs. Parasitism significantly affected tarsus length, T cell response, immunoglobulin and leucocyte concentrations. We found evidence of strong environmental effects on nestling body mass, body condition, wing length and tarsus length, and evidence of significant additive genetic variance for wing length and haematocrit. We found significant environmental variance, but no significant additive genetic variance in immune response parameters such as T cell response to the antigenic phytohemagglutinin, immunoglobulins, and relative and absolute numbers of leucocytes. Environmental variances were generally greater than additive genetic variances, and the low heritabilities of phenotypic traits were mainly a consequence of large environmental variances and small additive genetic variances. Hence, highly social bird species such as the house martin, which are subject to intense selection by parasites, have a limited scope for immediate microevolutionary response to selection because of low heritabilities, but also a limited scope for long-term response to selection because evolvability as indicated by small additive genetic coefficients of variation is weak.

Immunocompetence and nestling survival in the house martin: the tasty chick hypothesis

In altricial birds post-fledging survival is usually positively related to nestling body mass. A large number of studies have shown that the latest hatched chick is the more likely to die, even if food is abundant. Here we suggest that ectoparasites may be a key factor in the evolution and the maintenance of the establishment of weight hierarchies within broods. We prepose the hypothesis that weight hierarchies within broods may be adaptive if the chick in poor condition is the one with the least efficient immune system within a nest. In this case parasites would preferentially feed on such a "tasty chick", because it would allow high reproductive rates for the parasites, without negatively affecting the survival of the other nestlings. This could prevent entire nest failure of the brood or allow the other chicks to grow more efficiently. This hypothesis was investigated in a colony of house martins Delichon urbica. We predicted that immunocompetence was positively correlated with body condition, and that nestlings dying before hedging should have lower immune responses when challenged with an antigen. T-cell immune response to an experimentally injected antigen was strongly positively related to body condition. Non-surviving chicks had low body condition and a weak immune response. The implications of these results are discussed in the context of the adaptive significance of hatching asynchrony.

Evidence against close linkage of the loci for fraXq of Martin-Bell syndrome and for factor IX.

Linkage between the loci for fraXq of Martin-Bell syndrome and factor IX was studied in nine families exhibiting this syndrome by means of a restriction fragment length polymorphism at the factor IX locus. Computer analysis of the data indicates there to be no evidence for close linkage between the syndrome and the factor IX locus.

Transglutaminase 1-deficient recessive lamellar ichthyosis associated with a LINE-1 insertion in Jack Russell terrier dogs.

BACKGROUND: Congenital, nonepidermolytic cornification disorders phenotypically resembling human autosomal recessive ichthyosis have been described in purebred dog breeds, including Jack Russell terrier (JRT) dogs. One cause of gene mutation important to humans and dogs is transposon insertions. OBJECTIVES: To describe an autosomal recessive, severe nonepidermolytic ichthyosis resembling lamellar ichthyosis (LI) in JRT dogs due to insertion of a long interspersed nucleotide element (LINE-1) in the transglutaminase 1 (TGM1) gene. METHODS: Dogs were evaluated clinically, and skin samples were examined by light and electron microscopy. Phenotypic information and genotyping with a canine microsatellite marker suggested TGM1 to be a candidate gene. Genomic DNA samples and cDNA generated from epidermal RNA were examined. Consequences of the mutation were evaluated by Western blotting, quantitative reverse transcription-polymerase chain reaction (RT-PCR) and enzyme activity from cultured keratinocytes. RESULTS: Affected dogs had generalized severe hyperkeratosis. Histological examination defined laminated to compact hyperkeratosis without epidermolysis; ultrastructurally, cornified envelopes were thin. Affected dogs were homozygous for a 1980-bp insertion within intron 9 of TGM1. The sequence of the insertion was that of a canine LINE-1 element. Quantitative RT-PCR indicated a significant decrease in TGM1 mRNA in affected dogs compared with wild-type. TGM1 protein was markedly decreased on immunoblotting, and membrane-associated enzyme activity was diminished in affected dogs. CONCLUSIONS: Based on morphological and molecular features, this disease is homologous with TGM1-deficient LI in humans, clinically models LI better than the genetically modified mouse and represents its first spontaneous animal model. This is the first reported form of LI due to transposon insertion.

Approches exégétiques du Deutéronome. Brève histoire de la recherche sur le Deutéronome depuis Martin Noth.

Depuis la parution des Überlieferungsgeschitliche Studien de Martin Noth, le livre du Deutéronome joue un rôle central dans la discussion exégétique. L'A. cherche à faire le point sur le chemin parcouru depuis cinquante ans. Au niveau diachronique, aucun consensus n'apparaît sur les questions de la datation et des rédactions successives. Le modèle le plus performant semble être Deutéronome primitif sous Josias suivi à l'époque de l'exil de son insertion dans l'historiographie, puis de plusieurs retouches rédactionnelles. Au niveau théologique, les thèmes de la loi, de l'alliance, du pays, de l'exode et des pères en sont l'épine dorsale

Mortinatalité et mortalité infantile dans le canton du Valais

[Table des matières] Caractéristiques des naissances, 1979-1985. Evolution séculaire des mortalités néonatale, post-néonatale et infantile par sexe, 1901-1987 (données quinquennales). Evolution de la mortinatalité par sexe, 1969-1987. Taux de mortalité, canton de Valais, 1979-1985(87).