Mitogenomic evaluation of the historical biogeography of cichlids toward reliable dating of teleostean divergences

Background  

Recent advances in DNA sequencing and computation offer the opportunity for reliable estimates of divergence times between organisms based on molecular data. Bayesian estimations of divergence times that do not assume the molecular clock use time constraints at multiple nodes, usually based on the fossil records, as major boundary conditions. However, the fossil records of bony fishes may not adequately provide effective time constraints at multiple nodes. We explored an alternative source of time constraints in teleostean phylogeny by evaluating a biogeographic hypothesis concerning freshwater fishes from the family Cichlidae (Perciformes: Labroidei).     

Grid map analysis and its application for detecting vegetation changes in Japan

Abstract. Grid maps are used as a basic vegetation data base in Japan; they are simplified from vector-based vegetation maps. We estimated the frequency error or lack of information corresponding to reduced resolution and examined the reliable limits of this data base. We produced 10 grid maps on five different scales from 50 m to 1000 m using two different methods using both the whole cell (W-method) and only the central circle (C-method) from a vegetation map at scale 1: 25 000. We found that patches larger than the area of a cell on a vector-based map could be kept almost certainly on any map, but many patches of less than the cell size were lost. The number of missing patches with the C-method is fewer at every scale than those with the W-method. Though the value of Morisita's Cλ (p) index showed that the similarity with the original map was high - from the 50-m to the 200-m resolution - it was increasingly lower on the 400-m and 1000-m grid maps. The values of the Shannon index on the original map, 50-m and 100-m grid maps were not different, but they decreased from the 200-m to 1000-m grid maps. Because the vegetation data base of the Japanese Environment Agency used a 1000-m C-method grid map, we found that much information on patches less than 100 ha had disappeared. Information about dominant vegetation or large patches is almost accurate in this data base.     

Evolution of multiple phosphodiesterase isoforms in stickleback involved in cAMP signal transduction pathway

Background  

Duplicate genes are considered to have evolved through the partitioning of ancestral functions among duplicates (subfunctionalization) and/or the acquisition of novel functions from a beneficial mutation (neofunctionalization). Additionally, an increase in gene dosage resulting from duplication may also confer an advantageous effect, as has been suggested for histone, tRNA, and rRNA genes. Currently, there is little understanding of the effect of increased gene dosage on subcellular networks like signal transduction pathways. Addressing this issue may provide further insights into the evolution by gene duplication.