Mapping Complex Brain Torque Components and Their Genetic and Phenomic Architecture in 24,112 healthy individuals

The mechanisms determining the development and individual variability of brain torque (BT) remain unclear. Here, all relevant components of BT were analyzed using neuroimaging data of up to 24,112 individuals from 6 cohorts. Our large-scale data confirmed the population-level predominance of the typical anticlockwise torque and suggested a “first attenuating, then enlarging” dynamic across the lifespan primarily for frontal, occipital and perisylvian BT features. Sex/handedness differences in BT were found and were related to cognitive sex/handedness differences in verbal-numerical reasoning. We observed differential heritability of up to 56% for BT, especially in temporal language areas, and identified numerous genome- and phenome-wide significant associations pointing to neurodevelopment, cognitive functions, lifestyle, neurological and psychiatric disorders, sociodemographic, cardiovascular and anthropometric traits. This study provides a comprehensive description of BT and insights into biological and other factors that may contribute to the development and individual variations of BT.

Evaluation of Maize (Zea mays L.) Half Sib Recurrent Families for Expected Response and Percent Gain Per Cycle

Recurrent Selection (RS) or reselection generation after generation is a vital selection scheme for improving the physio-morphic traits and grain yield in maize populations. The objective of the present research was to determine the response of recurrent selection in CIMMYT maize population CZP-132011 for physio-morphic traits and to estimate selection differential, heritability, expected response and percent gain cycle-1 among the half sib recurrent families for morphological traits and grain yield. Sixty four half sib recurrent families were evaluated in 8×8 lattice square design with two replications at Cereal Crops Research Institute (CCRI), Pirsabak during 2017. Results showed highly significant differences among the half sib families for all the studied traits. Selection differential values were negative for days to tasseling (-3.00), anthesis (-3.08), silking (-3.10), anthesis silking interval (-1.14), plant height (-5.07) and ear height (-7.73). High heritability values (h2 ˃ 0.60) were recorded for all traits except plant height (0.55) which exhibited moderate heritability. Based on broad sense heritability and selection differential, expected response were observed negative for days to tasseling (-2.39), anthesis (-2.56), silking (-2.64), anthesis silking interval (-0.79), plant height (-2.81) and ear height (-5.22). After one cycle of recurrent selection using half sib families, the gain cycle-1 values were negative for (-0.39), anthesis (-0.47), silking (-1.44), anthesis silking interval (-3.17), plant height (-2.34) and ear height (-4.90). Based on the findings of current research it could be concluded that recurrent selection method was found effective in improving the CIMMYT maize source population CZP-132011 for physio-morphic traits.

The Differential Heritability of Regular Tobacco Use Based on Method of Administration

Several large studies have demonstrated that the liability to smoke cigarettes is strongly genetically influenced. However, the role of genetic and environmental risk factors in the use of other common forms of tobacco use has yet to be studied. Data on the regular use of cigarettes, cigars, pipes, dip (moist snuff), and chewing tobacco from 2634 male twins were analyzed with ACE structural equation models. Twin similarity for regular cigarette and dip use was largely genetic in origin. However, twin resemblance for chewing tobacco was just about equally the result of genes and shared environment, and twin similarity for use of pipes and cigars was entirely the result of shared environmental factors. Thus, the genetic influences on the liability for regular tobacco use appear to vary based on tobacco type. The causes for the use of different forms of tobacco are complex and worthy of further study.