26 research outputs found
A saturated consensus linkage map of Picea abies including AFLP, SSR, STS, 5S rDNA and morphological markers
International audienc
Do maternal environmental conditions during reproductive development induce genotypic selection in Picea abies?
In forest trees, environmental conditions during reproduction can greatly
influence progeny performance. This phenomenon probably results from
adaptive phenotypic plasticity but also may be associated with genotypic
selection. In order to determine whether selective effects during the
reproduction are environment specific, single pair-crosses of Norway spruce
were studied in two contrasted maternal environments (warm and cold
conditions). One family expressed large and the other small phenotypic
differences between these crossing environments. The inheritance of genetic
polymorphism was analysed at the seed stage. Four parental genetic maps
covering 66 to 78% of the genome were constructed using 190 to 200 loci.
After correcting for multiple testing, there is no evidence of locus under
strong and repeatable selection. The maternal environment could thus only
induce limited genotypic-selection effects during reproductive steps, and
performance of progenies may be mainly affected by a long-lasting epigenetic
memory regulated by temperature and photoperiod prevailing during seed
production.L'environnement maternel induit-il une sélection génotypique
durant les différents stades de reproduction chez Picea
abies ?. Chez les arbres forestiers, les conditions environnementales durant la
reproduction peuvent influencer les performances des descendants. Ce
phénomÚne reflÚte probablement la plasticité
phĂ©notypique, mais Ă©galement il pourrait ĂȘtre associĂ© Ă une
sélection génotypique. Afin de déterminer si des effets
sélectifs durant la reproduction sont spécifiques d'un environnement
donné, deux familles d'épicéa commun non apparentées ont
été obtenues par croisements dirigés dans deux environnements
maternels contrastés (conditions chaude et froide). La premiÚre
famille exprimait de larges différences phénotypiques entre les deux
environnements tandis que la seconde ne montrait pas de différence
significative. La transmission des polymorphismes génétiques a
été étudiée au stade de la graine. Quatre cartes
génétiques parentales couvrant 66 à 78 % du génome ont
été construites. Aucun effet de sélection n'a été mis en
évidence aux différents locus étudiés. L'environnement
maternel n'induirait donc que des effets de sélection génotypique
relativement faibles durant les stades de la reproduction. Les performances
des descendants seraient principalement affectées par une mémoire
épigénétique durable régulée par la température et
la photopériode régnant durant la production des graines
Molecular Evolution of Regulatory Genes in Spruces from Different Species and Continents: Heterogeneous Patterns of Linkage Disequilibrium and Selection but Correlated Recent Demographic Changes
Genes involved in transcription regulation may represent valuable targets in association genetics studies because of their key roles in plant development and potential selection at the molecular level. Selection and demographic signatures at the sequence level were investigated for five regulatory genes belonging to the knox-I family (KN1, KN2, KN3, KN4) and the HD-Zip III family (HB-3) in three Picea species affected by post-glacial recolonization in North America and Europe. To disentangle neutral and selective forces and estimate linkage disequilibrium (LD) on a gene basis, complete or nearly complete gene sequences were analysed. Nucleotide variation within species, haplotype structure, LD, and neutrality tests, in addition to coalescent simulations based on Tajimaâs D and Fay and Wuâs H, were estimated. Nucleotide diversity was generally low in all species (average ÏÂ =Â 0.002â0.003) and much heterogeneity was seen in LD and selection signatures among genes and species. Most of the genes harboured an excess of both rare and frequent alleles in the three species. Simulations showed that this excess was significantly higher than that expected under neutrality and a bottleneck during the Last Glacial Maximum followed by population expansion at the Pleistocene/Holocene boundary or shortly after best explains the correlated sequence patterns. These results indicate that despite recent large demographic changes in the three boreal species from two continents, species-specific selection signatures could still be detected from the analysis of nearly complete regulatory gene sequences. Such different signatures indicate differential subfunctionalization of gene family members in the three congeneric species
Genomic organization of molecular differentiation in Norway spruce (Picea abies)
International audienc
Characterization of hybrids between Larix Decidua and L. Kaempferi by molecular markers
National audienc
Characterization of hybrids between Larix Decidua and L. Kaempferi by molecular markers
National audienc