Statistical equivalent of the classical TDT for quantitative traits and multivariate phenotypes

Clinical end-point traits are usually governed by quantitative precursors. Hence, there is active research interest in developing statistical methods for association mapping of quantitative traits. Unlike population-based tests for association, family-based tests for transmission disequilibrium are protected against population stratification. In this study, we propose a logistic regression model to test the association for quantitative traits based on a trio design. We show that the method can be viewed as a direct extension of the classical transmission diequilibrium test for binary traits to quantitative traits. We evaluate the performance of our method using extensive simulations and compare it with an existing method, family-based association test. We found that the two methods yield comparable powers if all families are considered. However, unlike FBAT, which yields an inflated rate of false positives when noninformative trios with all three individuals’ heterozygous are removed, our method maintains the correct size without compromising too much on power. We show that our method can be easily modified to incorporate multivariate phenotypes. Here, we applied this method to analyse a quantitative endophenotype associated with alcoholism.     

FIRST RECORD OF AN AQUATIC BEETLE LARVA (INSECTA: COLEOPTERA) FROM THE PARSORA FORMATION (PERMO-TRIASSIC), INDIA

Abstract:  The fossilized larva of an aquatic beetle, Protodytiscus johillaensis gen. et sp. nov., is described from a ferruginous micaceous siltstone bed of the Permo-Triassic Parsora Formation of the South Rewa Gondwana Basin, Madhya Pradesh, India, and its systematic position and ordinal relationships within the coleopterous suborder Adephaga are discussed. Hitherto, the oldest known fossils of the hydradephagan superfamily Dytiscoidea have been Jurassic. The discovery of P. johillaensis extends the range of the Dytiscoidea back to the Permo-Triassic period.     

Changes in Nucleic Acids Associated with Maturation and Senescence in Hedera helix

Significant changes in nucleic acids are associated with both maturation and senescence of Hedera helix leaf tissues. DNA content was unaffected by senescence, and there were no quantitative differences between juvenile and transitional forms. The adult tissue, however, contained less DNA than the other forms. The total RNA content was reduced by senescence in juvenile and transitional tissue but not in adult. Maturation, on the other hand, progressively decreased the total RNA content. Similar changes in sRNA and rRNA indicate that maturation involves quantitative changes in these fractions. Quantitative differences in the nucleotide analyses suggest that different sRNA and rRNA species are responsible for the biological processes associated with maturation.     

A new genus of podonomine midge (Chironomidae) from Bhutan

A new monobasic genus of Podonominae, Neopodonomus, and its type-species, N. similis are described from nine males and four females collected in Bhutan. This represents the first record of Podonominae from the Oriental region.