The effects of maturation on self-induced dynamic body sway frequencies of girls performing acrobatics or classical dance

We investigated the effects of maturation on the dynamic body sways of healthy girls. Prepubertal and postpubertal girls practising professional physical activities requiring a good ability to maintain equilibrium (acrobats and dancers) were asked to stand on a free seesaw platform and the results compared to those for untrained age-matched girls. This platform (stabilometer) allows self-induced body sways. Stabilograms were obtained by a double integration of the angular acceleration from the recordings of the platform sways made with an accelerometer. Fast Fourier transform processing of stabilograms allowed spectral frequency analysis. The total spectrum energy and the energies of three frequency bands (0–0.5 Hz, 0.5–2 Hz, 2–20 Hz) were determined. ANOVA showed that, for all groups of different equilibrium activity and independent of visual input, prepubertal girls had higher energy values than postpubertal girls in the 0- to 0.5-Hz band whereas the opposite was true for 0.5- to 2-Hz band. Ballet dancers were more dependent than acrobats on visual inputs for the regulation of their postural control but were less dependent than untrained girls at both ages. Maturation seemed to shift body sways towards higher frequencies and the utilization of the cues of postural control was different according to the type of equilibrium activity practised by the subjects. Accepted: 7 February 1997     

The γ-crystallin gene families: Sequence and evolutionary patterns

Summary The -crystallin proteins consist of two topologically equivalent domains, each built up out of two similar motifs. They are encoded by a gene family, which already contained five members before the divergence of rodents and primates. A further gene duplication took place in each lineage. To analyze the pattern of evolution within this gene family, the coding sequences of six human genes, six rat genes, and four mouse genes were compared. Between species, a uniform rate of evolution of all regions of the protein is seen. The ratio of synonymous to nonsynonymous substitution in the human/rat or human/mouse comparison is much lower than the ratio when rat and mouse are compared indicating that the -crystallin proteins are better conserved in the rodent lineage. Within species, the regions encoding the two external motifs I and III of the protein show a greater extent of nonsynonymous substitution than the regions encoding the two internal protein motifs II and IV. The low extent of synonymous substitution between the second exons (encoding motifs I and II) of the rat -crystallin genes suggests the frequent occurrence of gene conversion. In contrast, a high extent of synonymous substitution is found in exon 3 (encoding motifs III and IV) of the rat genes. The same phenomenon is seen within the human gene family. The frequencies of occurrence of the various dinucleotides deviate less from those predicted from the frequencies of occurrence of each individual nucleotide in the second exons than in the third exons. The sequences of the third exons are significantly depleted in CpG, ApA, and GpT and enriched in CpT and GpA.     

HLA gene and haplotype frequencies in galicia (NW Spain)

The genetic structure of six populations of Iran (Turks, Kurds, Lurs, Zabolis, Baluchis and Zoroastrians) was examined using data on blood groups, serum proteins and cell enzymes. Our results show conclusively that there are genetic differences among the six populations and the analysis of superimposed R and S matrices defined by Harpending & Jenkins (1973) show that the dispersion of some of the alleles correspond to the dispersion of the populations. The F_ST estimates are not large enough to favour selection on any of the loci studied. The F_IT and F_IS estimates are positive and moderately high suggesting that the genetic differentiation to some extent is influenced by inbreeding.     

Selection and Inbreeding of Heterodera glycines on Glycine max

Few soybean cyst nematodes (SCN), Heterodera glycines, of a diverse gene pool developed into females on soybeans PI 89772 or PI 209332. Nematodes surviving the selection pressure were then inbred for nine generations by single cyst transfers on the same selecting soybean line. These nematodes appeared to tolerate concurrent selection and inbreeding. Effects of selection-inbreeding, selection only, and secondary selection were evaluated by relative ability to produce cysts on 11 soybean lines. The genetic differences of PI 89772 (also Peking and Pickett 71) and PI 209332 were reaffirmed. The random effects of inbreeding indicated that Ilsoy and Williams may have genes for resistance different from those in PI 89772 or PI 209332. Egg inoculum obtained from soil resulted in very few cysts in some tests. Fresh egg inoculum (from cysts on 27-30-day-old plants) generally resulted in more cysts and more consistent results. Concurrent with the change in inoculum, there was a large increase in relative numbers of cysts on several soybean lines but no change on other lines; the true cause of this large interaction is unknown. Secondary selection of two inbreds was effective and suppressed cyst numbers on the line on which one inbred was selected initially. These results are consistent with the allelism linkage of some SCN genes reported previously.     

Temporal variation of allele frequencies in populations of Akodon dolores (Rodentia,Cricetidae)

Summary Six population samples of the South American cricetid rodent Akodon dolores were collected at the same site at six-month intervals over a three year period. Changes in density were detected. Seven out of 18 loci analyzed by means of starch gel electrophoresis were polymorphic. Only two of these loci (Est-4 and G6pdh) showed statistically significant variation in allele frequencies following a seasonal pattern. There was no correlation between allele frequencies and population density. When animals were grouped into two classes according to body weight, a clear difference in allele distribution at the Est-4 and G6pdh loci was observed between individuals 39 g or less and those heavier than 39 g. As the first group comprises predominantly younger animals, the data indicate that changes in the age-structure of population, rather than density variations, are responsible for the cyclic pattern of allele frequencies fluctuations.     

Genetic variation in North Africa and Eurasia: Neolithic demic diffusion vs. paleolithic colonisation

The hypothesis that both genetic and linguistic similarities among Eurasian and North African populations are due to demic diffusion of neolithic farmers is tested against a wide database of allele frequencies. Demic diffusion of farming and languages from the Near East should have determined clines in areas defined by linguistic criteria; the alternative hypothesis of cultural transmission does not predict clines. Spatial autocorrelation analysis shows significant gradients in three of the four linguistic families supposedly affected by neolithic demic diffusion; the Afroasiatic family is the exception. Many such gradients are not observed when populations are jointly analyzed, regardless of linguistic classification. This is incompatible with the hypothesis that major cultural transformations in Eurasia (diffusion of related languages and spread of agriculture) took place without major demographic changes. The model of demic diffusion seems therefore to provide a mechanism explaining coevolution of linguistic and biological traits in much of the Old World. Archaeological, linguistic, and genetic evidence agree in suggesting a multidirectional process of gene flow from the Near East in the neolithic. However, the possibility should be envisaged that some allele frequency patterns can predate the neolithic and depend on the initial spread of Homo sapiens sapiens from Africa into Eurasia. © 1994 Wiley-Liss, Inc.     

Effects of stripe rust on the evolution of genetically diverse wheat populations

Summary Eighteen populations, composed of four wheat (Triticum aestivum) varieties that were originally mixed together at equal frequencies, were grown for one-to-three generations at two locations. In addition, pure stands of the four varieties were grown in each year. Populations were either exposed to two stripe rust (Puccinia striiformis) races, protected from stripe rust, or exposed to alternating years of diseased and disease-free conditions. Regression of the logit of a variety's frequency versus generation number was used to calculate the relative fitness of each variety in each population. These analyses suggest that the relative fitnesses of the wheat varieties were affected by disease and geographic location and were constant over time. However, frequency-changes of varieties in the mixtures were negatively correlated with their planting frequencies (0.0001 < P < 0.085 in 14 out of 16 cases), suggesting that fitnesses were frequency-dependent in both the presence and absence of disease. We hypothesize that failure to detect frequency-dependence of fitness in the logit analyses was due to a limited number of generations and a limited range of initial variety frequencies. This is supported by data from longer-term studies in the literature that provide evidence for frequency-dependence of fitness in plant mixtures. Analyses of currently available field data suggest that stable equilibria may be a more likely outcome for mixtures of varieties that are more closely related and/or more uniformly adapted to the environment in which they are grown.Paper No. 9820 of the journal series of the Oregon Agricultural Experiment Station.     

Acoustic structure of vocalization and stapedius muscle activity during vocal development in chickens (Gallus gallus)

The link between stapedius muscle activity and acoustic structure of vocalization was analysed in cocks of age 20–30 to 90–100 days old. The results show that stapedius muscle activation depends on the acoustic structure of vocalization and changes during vocal development. This dependence was observed in spontaneous calls and in vocalizations elicited by stimulating the mesencephalic calling area. In 30-day-old cocks stapedius muscle EMG response is never associated with vocalizations with an acoustic energy content which is always distributed at frequencies higher than 2000 Hz. The coupling between vocalization and stapedius muscle activity begins later, when birds produce vocalizations with acoustic energy shifted towards lower frequencies. Overall, stapedius muscle activity is related to a bird's production of high amplitude low frequencies. These results support the hypothesis that the primary role of the stapedius muscle during normal vocal development is to dampen the amplitude of low frequency energy that reaches the cochlea during vocalization.     

转铁蛋白分型及其基因频率分布

用固相pH梯度(pH 5.05～5.60)等电聚焦技术对随机抽取的188名北京地区健康汉族人的血清转铁蛋白(Tf)进行分型调查,并统计基因频率,检出了在中国还未见报道的Tf^C3基因.其表型分别是：TfC1, TfC2, TfC1C2, TfC1C3, TfC1Dchi, TfC2Dchi.Tf^C1=0.7420, Tf^C2=0.2420, Tf^C3=0.0027, Tf^Dchi=0.0133, 符合Hardy-Weinberg定律, 并与其他已见报道的汉族 Tf基因频率大致相符.