First microsatellite markers for Paspalum plicatulum (Poaceae) characterization and cross-amplification in different Paspalum species of the Plicatula group.

Paspalum plicatulum is a perennial rhizomatous grass with natural diploid and polyploid cytotypes. It is a member of Plicatula, which has historically been recognized as a highly complex group containing species of ecological, ornamental and forage importance. The complex nature of the P. plicatulum genome makes it a challenging species for genetic research. This study aimed to develop and characterize microsatellite molecular markers in P. plicatulum and to evaluate their transferability to other Plicatula group species

Estabelecimento de padrão genético molecular para sete cultivares de pimenteira-do-reino Piper nigrum L. (Piperaceae) utilizando microssatélite.

O Brasil, juntamente com países Asiáticos, compõe o grupo dos maiores exportadores de pimenta-do-reino, Piper nigrum L., especiaria mais consumida mundialmente. No Pará, estado com maior produção do país, cultiva-se em torno de quatro cultivares nas áreas de produção. Atualmente a identificação das cultivares plantadas é feita utilizando caracteres morfo-agronômicos. Contudo, há dificuldade de identificação das cultivares utilizadas comercialmente pelos produtores que recebem nomes diversos em áreas de produção. O objetivo desse trabalho foi estabelecer o padrão genético de cultivares de Piper nigrum L. utilizando marcadores moleculares microssatélites. A metodologia utilizada foi extração de DNA de plantas de sete cultivares conservadas no banco de germoplasma da Embrapa Amazônia Oriental, amplificação de fragmentos utilizando nove loci microssatelites polimorficos e a genotipagem em gel desnaturante de poliacrilamida corado com prata, Os resultados mostraram diferenças entre as cultivares analisadas com nítidos agrupamentos distintos, sendo o método eficiente para estabelecer padrão genético molecular das cultivares de pimenteira-do-reino

The multi-peak adaptive landscape of crocodylomorph body size evolution

Background: Little is known about the long-term patterns of body size evolution in Crocodylomorpha, the > 200-million-year-old group that includes living crocodylians and their extinct relatives. Extant crocodylians are mostly large-bodied (3–7 m) predators. However, extinct crocodylomorphs exhibit a wider range of phenotypes, and many of the earliest taxa were much smaller ( Results: Crocodylomorphs reached an early peak in body size disparity during the Late Jurassic, and underwent an essentially continual decline since then. A multi-peak Ornstein-Uhlenbeck model outperforms all other evolutionary models fitted to our data (including both uniform and non-uniform), indicating that the macroevolutionary dynamics of crocodylomorph body size are better described within the concept of an adaptive landscape, with most body size variation emerging after shifts to new macroevolutionary regimes (analogous to adaptive zones). We did not find support for a consistent evolutionary trend towards larger sizes among lineages (i.e., Cope’s rule), or strong correlations of body size with climate. Instead, the intermediate to large body sizes of some crocodylomorphs are better explained by group-specific adaptations. In particular, the evolution of a more aquatic lifestyle (especially marine) correlates with increases in average body size, though not without exceptions. Conclusions: Shifts between macroevolutionary regimes provide a better explanation of crocodylomorph body size evolution on large phylogenetic and temporal scales, suggesting a central role for lineage-specific adaptations rather than climatic forcing. Shifts leading to larger body sizes occurred in most aquatic and semi-aquatic groups. This, combined with extinctions of groups occupying smaller body size regimes (particularly during the Late Cretaceous and Cenozoic), gave rise to the upward-shifted body size distribution of extant crocodylomorphs compared to their smaller-bodied terrestrial ancestors.</p

Isolation and characterization of microsatellite loci in the black pepper, Piper nigrum L. (piperaceae).

Disponível também on-line