AGT M235T Genotype/Anxiety Interaction and Gender in the HyperGEN Study

BACKGROUND. Both anxiety and elevated heart rate (HR) have been implicated in the development of hypertension. The HyperGen cohort, consisting of siblings with severe and mild hypertension, an age-matched random sample of persons from the same base populations, and unmedicated adult offspring of the hypertensive siblings (N=1,002 men and 987 women), was analyzed for an association of the angiotenisinogen AGTM235T genotype (TT, MT, MM) with an endophenotype, heart rate (HR) in high and low anxious groups. METHODOLOGY. The interaction of AGTM genotype with anxiety, which has been independently associated with hypertension, was investigated adjusting for age, hypertension status, smoking, alcohol consumption, beta blocker medication, body mass index, physical activity and hours of television viewing (sedentary life style). PRINCIPAL FINDINGS. Although there was no main effect of genotype on HR in men or women, high anxious men with the TT genotype had high HR, whereas high anxious men with the MM genotype had low HR. In women, HR was inversely associated with anxiety but there was no interaction with genotype. CONCLUSION/SIGNIFICANCE. The results suggest that high anxiety in men with the TT genotype may increase risk for hypertension whereas the MM genotype may be protective in high anxious men. This type of gene x environment interaction may be one reason why genome wide association studies sometimes fail to replicate. The locus may be important only in combination with certain environmental factors.National Heart, Lung and Blood Institute (UT FC, HL54472, HL54473, HL54495, HL54496, HL54497, HL54509, HL54515

Genomic imprinting and parent-of-origin effects on complex traits

Parent-of-origin effects occur when the phenotypic effect of an allele depends on whether it is inherited from an individual’s mother or father. Several phenomena can cause parent-of-origin effects, with the best characterized being parent-of-origin dependent gene expression associated with genomic imprinting. Imprinting plays a critical role in a diversity of biological processes and in certain contexts it structures epigenetic relationships between DNA sequence and phenotypic variation. The development of new mapping approaches applied to the growing abundance of genomic data has demonstrated that imprinted genes can be important contributors to complex trait variation. Therefore, to understand the genetic architecture and evolution of complex traits, including complex diseases and traits of agricultural importance, it is crucial to account for these parent-of-origin effects. Here we discuss patterns of phenotypic variation associated with imprinting, evidence supporting its role in complex trait variation, and approaches for identifying its molecular signatures

Preliminary observations on effects of haemoglobin genotype and estimate of genetic distance at the HB locus in West African dwarf and red Sokoto goats

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Discriminant analysis of morphometric differentiation in the West African Dwarf and Red Sokoto goats

This study evaluated the usefulness of morphological characteristics to distinguish two important indigenous goat breeds in Nigeria. Fifteen morphometric traits were measured on West African Dwarf – WAD (n = 160) and Red Sokoto – RS (n = 142) goats that ranged in age of up to 19 months and were reared extensively in villages in southern and northern Nigeria. Univariate analysis revealed that the body measures of RS goats were significantly higher than those of WAD goats. Canonical discriminant analysis gave better resolution, as only seven external morphological characteristics of strong discriminating power were extracted. The most discriminant variable between the two goat populations was rump height, followed in order by body length, horn length, face length, chest girth, neck circumference and head width. The discriminant function obtained correctly classified 100% of individuals from the sample of known goat populations. The classification accuracy of the function was cross-validated using the split-sample method, and indicated a 99.7% success rate (99.4% of WAD goats and 100% of RS goats were correctly assigned to their source genetic group). This study indicates that a discriminant tool may be used successfully in the field to separate WAD and RS goats. The present results could be complemented by molecular characterization using DNA markers for better management and conservation strategies of genetic resources for indigenous goats

Urinary norepinephrine and epinephrine excretion rates are heritable, but not associated with office and ambulatory blood pressure

Genetic and environmental contributions to urinary excretion rates of norepinephrine (UNEV) and epinephrine (UEV) and their association with blood pressure (BP) were investigated in 91 African American (mean age, 17.3 +/- 2.6 years) and 101 European American (mean age, 18.7 +/- 3.4 years) mono- and di-zygotic twins. Genetic modeling was performed using Mx software. UNEV (1.9 +/- 1.3 mu g h(-1)) and UEV (0.2 +/- 0.2 mu g h(-1)) were highly correlated (r = 0.81, P < 0.001). Significant heritabilities for UNEV (0.68) and UEV (0.74) without ethnic and gender effects were observed. The genetic correlation between UNEV and UEV was 0.86. There was no clear pattern of correlations for UNEV and UEV with BP measures in European Americans, but African Americans showed some inverse correlations of moderate size. Measurements of UNEV and UEV provide a viable method for the study of sympathetic tone and are substantially heritable. Hypertension Research (2012) 35, 1164-1170; doi:10.1038/hr.2012.104; published online 12 July 2012