Molecular and evolutionary analyses of formyl peptide receptors suggest the absence of VNO-specific FPRs in primates

Formyl peptide receptors (FPRs) were observed to expand in rodents and were recently suggested as candidate vomeronasal chemosensory receptors. Since vomeronasal chemosensory receptors usually underwent positive selection and evolved concordantly with the vomeronasal organ (VNO) morphology, we surveyed FPRs in primates in which VNO morphology is greatly diverse and thus it would provide us a clearer view of VNO-FPRs evolution. By screening available primate genome sequences, we obtained the FPR repertoires in representative primate species. As a result, we did not find FPR family size expansion in primates. Further analyses showed no evolutionary force variance between primates with or without VNO structure, which indicated that there was no functional divergence among primates FPRs. Our results suggest that primates lack the VNO-specific FPRs and the FPR expansion is not a common phenomenon in mammals outside rodent lineage, regardless of VNO complexity.

PRELIMINARY-RESULTS OF GAAS SINGLE-CRYSTAL GROWTH UNDER HIGH GRAVITY CONDITIONS

GaAs single crystals have been grown under high gravity conditions, up to 9g0, by a recrystallization method with decreasing temperature. The impurity striations in GaAs grown under high gravity become weak and indistinct with smaller striation spacings. The dislocation density of surcharge-grown GaAs increases with increase of centrifugal force. The cathodoluminescence results also show worse perfection in the GaAs grown at high gravity than at normal earth gravity.