Evidence that the eumelanin restrictor genes (Co) and (Db) are present in the genome of the Buff Rock bantam

1. An investigation was conducted among the progeny from crosses between Buff Rock and Light Sussex bantams, and between Buff Rock and Gold‐Pencilled Hamburgh bantams in order to ascertain whether the eumelanin restrictor genes Columbian (Co) and Dark‐brown (Db) were present in the genome of the Buff Rock.

2. The Light Sussex and Gold‐Pencilled Hamburgh bantams used in this study were known to be Co/ Co db⁺ / db⁺ and co⁺ / co⁺ Db/ Db respectively.

3. In both F₂ generations the least eumelanin restricted segregants were as the parent mated with the Buff Rock, thus demonstrating the Buff Rock bantam tested to be Co/ Co Db/ Db, or possess similar alleles at these loci.

4. The Buff Rock bantam male was found to be heterozygous for a eumelanin inhibitor gene which appears to be dominant white (I).     

Geological rhythms and cometary impacts

Time-series analysis reveals two dominant, stable long-term periodicities approximately equal to 33 +/- 3 and 260 +/- 25 million years in the known series of geological and biological upheavals during the Phanerozoic Eon. Because the cycles of these episodes agree in period and phase with the cycles of impact cratering on Earth, these results suggest that periodic comet impacts strongly influence global tectonism and biological evolution. These two periodicities could arise from interactions of the solar system with interstellar clouds as the solar system moves cyclically through the Galaxy.     

Leaf herbivores decrease fitness of a tropical plant

Damage by insect herbivores to neighboring individuals of the shrub Piper arieianum in a neotropical wet forest varies greatly. This differential damage has a genetic basis and results in a 2-year decrease in growth, seed production, and seed viability, with larger plants recovering before smaller plants. The results provide evidence that leaf herbivores represent a potentially strong selective force for the evolution of plant defenses.     

Polychlorinated Dibenzo-p-dioxins and Dibenzofurans in Sediments from Siskiwit Lake, Isle Royale

Polychlorinated dibenzo-p-dioxins and dibenzofurans were found in sediment from Siskiwit Lake on Isle Royale, Lake Superior, a location which can receive only atmospheric inputs. The source of these compounds is the atmospheric transport of dioxins and furans formed by combustion of domestic and chemical waste.