Properdin factor B (Bf) polymorphism: Subtyping of SS phenotypes

The authors have studied the genetic polymorphism of the properdin factor B (Bf) by the isoelectrofocusing technique. The SS phenotypes, all similar on agarose gel electrophoresis, were shown to be heterogeneous after isoelectrofocusing; this heterogeneity corresponds to the expression of two new suballeles SA and SB, inherited in a codominant manner. Gene frequencies for 121 individuals with SS phenotype are 0.57 for SA, and 0.43 for SB.     

Systems of mate selection in a cockroach species with male dominance hierarchies

The system of mate selection in the cockroach, Nauphoeta cinerea, was studied experimentally. The dominant male in a group mates more often than expected if random mating were occurring. The presence of a female usually does not result in changes in the dominance hierarchy, but the frequency of certain behavioural patterns in intermale interactions changes after introduction of the female. Females can discriminate between dominant and non-dominant males on the basis of odour. The experimental approach to this question is somewhat confounded by turning tendencies of the females; data are presented relating female choice to turning tendency.     

Adult Triploids in a Rainbow Trout Family

Six triploid individuals were found in a full-sib family of 11 adult rainbow trout (Salmo gairdneri) from a domesticated hatchery stock. The triploid individuals were normal in size and external appearance, had underdeveloped gonads, and showed no evidence of 3n/2n chimerism or mosaicism. XXY triploids were males, suggesting that the Y chromosome is male determining in trout. Because they may avoid production losses associated with sexual maturation in normal fish, triploid trout and salmon could potentially be useful in fish culture.