Is there genetic structure in populations of Helicoverpa armigera from Australia?

Recent studies suggest that populations of the pest moth Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) may be genetically differentiated over short distances and time periods within Queensland, Australia. To test for genetic structure in another region of Australia, we characterized population differentiation in Victorian samples of H. armigera using eight microsatellite loci. We found no evidence of genetic structure among samples from different locations or among samples collected at different times. Moreover, Victorian samples were not differentiated from other samples of H. armigera from Queensland and New Zealand. All samples showed substantial deviations from Hardy–Weinberg equilibrium, suggesting a high frequency of null alleles typically found in microsatellites of Lepidoptera. These results indicate that populations of H. armigera are not strongly structured among regions in south‐eastern Australia.     

Geographical differentiation of allozymic variability in natural Indian populations ofDrosophila melanogaster

Fourteen Indian populations ofD. melanogaster collected along a 22° latitudinal range were analyzed electrophoretically to compare the geographical patterns of allozymic variation at 13 loci. The data show higher genetic differentiation on the basis of moderate to higherF _ST values and significant statistical correlation of allelic frequencies at six polymorphic loci with latitude. The results add support to the hypothesis that the occurrence of parallel or complementary latitudinal clines across different continental populations provides evidence of natural selection maintaining such clinal variation.     

Is there a plant interferon?

Plants appear to have a mechanism of acquired resistance to virus infection resembling the one which involves the interferon in mammals. In some virus-infected plants, anti-viral agents are produced which show similarities to animal interferon but it is not certain whether these are analogous to the anti-viral protein which is induced by interferon in animal cells. Acquired resistance to virus infection in plants also can be produced by a variety of non-viral agents—biotic and abiotic. In a few cases, interferon-like substances may mediate the resistance. Although many virus inhibitors of higher plant origin differ from the typical interferon because of their preformed (endogenous) character, some show other physico-chemical and biological similarities to the interferon. This is particularly true of a glycoprotein obtained fromPhytolacca spp. whose mechanism of virus inhibition closely resembles a mechanism postulated for the anti-viral protein induced by the interferon in animal cells. Many virus-plant combinations which produce local lesions and an acquired resistance to virus infection remain to be tested for their potential synthesis of induced anti-viral agents. These could be valuable in the therapy of plant and animal disease. The Caryophyllales (Centrospermae) are particularly promising in this regard.     

Normative genetic profiles of RAAS pathway gene polymorphisms in North Indian and South Indian populations

Population-based genetic association studies, popularly known as case-control studies, have continued to be the most preferred method for deciphering the genetic basis of various complex diseases, even in the post-human genome sequencing era. However, interpopulation differences in allele, genotype, and haplotype frequencies and linkage disequilibrium patterns lead to inconsistent results in candidate gene association studies. Therefore, for any meaningful disease association study, knowledge of the normative genetic background of the baseline population is a prerequisite. In addition, such genetic variation data also provide a ready-made menu of allele frequencies and linkage disequilibrium patterns of various polymorphisms in specific candidate genes in a particular population, which is a useful reference for further genetic association studies. Such genetic variation data are lacking for the Indian population, which represents about one-sixth of the world's population. In the present study we have reported the allele, genotype, and haplotype frequencies, Hardy-Weinberg equilibrium status, and linkage disequilibrium patterns of 12 polymorphisms in six candidate genes from the renin-angiotensin-aldosterone system among Indians. Because of their different history of origin, the Indian population is broadly divided into two subpopulations: North Indians (Caucasian Europeans) and South Indians (Dravidians). Considering this well-documented difference in gene pools, we have presented a comparative account of the normative genetic data of North Indian and South Indian populations with at least four individuals of urban and suburban origin from each of the representative states of northern and southern India.     

Is there a structural principle of the myocardium?

Up to now neither by macroscopical nor histological findings a structural principle of the myocardium could be found. The tremendous complexity in the various courses of myocardium fibres and connective tissue as well as the pump diagram of the heart as a functional reference of all heart actions point to aspects of the heart function as a determined chaos. This could be demonstrated by a simple structural principle of the myocardium namely the myocardium fibres and connective tissue strands are arranged in the form of intermeshed hyperboloids. These could be of interest in the construction of artificial hearts. These new insights in form and function of the myocardium allow to discuss in a new way normal and pathological functions of the heart and to develop new therapeutical approaches.     

Genetic differentiation and inversion clines in Indian natural populations of Drosophila melanogaster.

To study the genetic differentiation and inversion clines in Indian natural populations of Drosophila melanogaster, 14 natural populations (6 from the north and 8 from the south) were screened for chromosome inversions. The chromosomal analysis revealed the presence of 23 paracentric inversions, which include 4 common cosmopolitan, 4 rare cosmopolitan, 2 recurrent endemic, and 13 unique endemic (new inversions detected for the first time) inversions. The difference in karyotype frequencies between populations from the north and south were highly significant and the level of inversion heterozygosity was higher in populations from the south. Statistically significant negative correlations were found between each of the four common cosmopolitan inversions and latitude. These findings are in accord with results from other worldwide geographic regions and show that Indian populations of D. melanogaster have undergone considerable genetic differentiation at the level of inversion polymorphism.     

Is there a fetal gasoline syndrome?

Two children from a small Amerindian community presented with profound retardation, initial hypotonia progressing to hypertonia, scaphocephaly, a prominent occiput, poor postnatal head growth, and additional minor anomalies. Abuse of gasoline by inhalation was a widespread problem in the community, and gasoline inhalation during the pregnancy could be documented in both of the pregnancies. We are raising the question as to whether inhalation of gasoline during pregnancy may be teratogenic in humans.     

Is there a latitudinal gradient in seed production?

We compiled data from seed rain studies at 33 sites from around the world to determine whether the greater mean seed mass of tropical plants is associated with production of fewer seeds per square meter of ground. We found no significant linear relationship between latitude and annual seed rain density, but found some evidence for a mid‐latitude peak in seed rain density (quadratic relationship, p=0.018; R²=0.23). Combining seed rain data with seed mass data suggests that vegetation at the equator produces between 19 and 128 times more total mass of seed per year than does vegetation at 60°. This gradient in seed production would far outweigh the doubling in net primary productivity (NPP) over the same range of latitudes. Thus, our (admittedly small) dataset suggests that tropical vegetation allocates a much greater proportion of NPP to reproduction. This raises two important questions for the future: 1) why might tropical vegetation commit more energy to seed production than vegetation further from the equator? 2) What aspect of plant growth might receive proportionally less energy in tropical ecosystems?     

Is there a critical weight for oestrus in the ferret?

Information concerning the weight at the onset of a period of oestrus, the timing of oestrus, the age at first oestrus and the lighting conditions was collected from the records of 1364 ferrets and reviewed for evidence indicating that the animals became sexually mature around a particular, critical, weight. None was found, but the results suggest that there is a minimum weight, around 420 g, below which oestrus does not occur.