Nonrandom territory occupancy by nesting Gyrfalcons (Falco rusticolus)

We know little regarding how specific aspects of habitat influence spatial variation in site occupancy by Arctic wildlife, yet this information is fundamental to effective conservation. To address this information gap, we assessed occupancy of 84 Gyrfalcon (Falco rusticolus Linnaeus, 1758) breeding territories observed annually between 2004 and 2013 in western Alaska. In line with the theory of population regulation by site dependence, we asked whether Gyrfalcons exhibited a nonrandom pattern of site selection and if heterogeneous landscape attributes correlated with observed occupancy patterns. We characterized high- and low-occupancy breeding territories as those occupied more or less often than expected by chance, and we evaluated land cover at 1 and 15 km circles centered around nesting territories to identify habitat variables associated with observed occupancy patterns. We tested 15 competing models to rank hypotheses reflecting prey and habitat variables important to nesting Gyrfalcons. We confirmed a nonrandom pattern of site selection but found only weak evidence that the distribution of prey habitat was responsible for this pattern. We reason that preferential habitat use by nesting Gyrfalcons may be determined by spatial scales other than those we measured or may be driven by landscape-level attributes at time periods other than during the brood rearing period.

The pattern of seed formation in cauliflower (Brassica oleracea L. var. botrytis) with special reference to seed abortion

In cauliflower Brassica oleracea L. var. botrytis cv. Kibo Giant, patterns of seed abortion and development within developing siliques are nonrandom. All ovules were fertilized from 14 days after anthesis. However, only 70% of the ovules produced mature seeds. Cryptic seed abortion started early in silique ontogeny and reached a maximum at 28 days after anthesis. Ovules located in the middle zone of a silique produced more mature seeds than ovules in stylar and basal zones in that order. Ovules in the first three positions in the stylar zone (positions 1, 2, and 3) and ovules in the last four positions in basal zone (positions 19, 20, 21, and 22) showed higher rates of seed abortion. The nonrandom pattern of seed abortion within a silique is mainly due to partiality in the allocation of maternal resources to the developing ovules at different positions, which enhances maternal fecundity through resource conservation. It may also be due to temporal differences in fertilization, spatial advantage of seeds within the ovary, and superiority of the parental lineage.Key words: Brassica oleracea L. var. botrytis, seed development, seed abortion, maternal regulation, seed to ovule ratio.

Haemophilia B in Female Twins Caused by a Point Mutation in one Factor IX Gene and Nonrandom Inactivation Patterns of the X-Chromosomes

SummaryHaemophilia B is a X-linked recessive bleeding disorder with an incidence of 1:25,000-30,000 male birth. Usually female carriers are clinically normal. Phenotypic expression of the disease in female carriers is extremely rare.We describe cytogenetically inconspicuous female identical twins both with factor IX levels below 2%, prolonged bleeding after venipuncture as well as haematomas after intramuscular injections. The father, suffering from a severe haemophilia B, is deceased. By sequencing one point mutation was characterized in heterozygote condition in the factor EX gene of the probands at nt 17678. This mutation leads to the substitution cystein 88 to tyrosine in the growth factor domain of the factor IX. Investigation of the X-chromosomal inactivation by comparison of methylation patterns of genomic DNA at locus DXS255 after digestion with Pst I and Pst I +Hha I and hybridisation with the probe M27β indicated a nonrandom pattern of X-chromosomal inactivation in the twins. In both girls, only the paternal X-chromosome was the active one leading to the phenotypic expression of haemophilia in the female carriers.