Eye color: A potential indicator of alcohol dependence risk in European Americans

HERCing: Structural and Functional Relevance of the Large HERC Ubiquitin Ligases

Homologous to the E6AP carboxyl terminus (HECT) and regulator of chromosome condensation 1 (RCC1)-like domain-containing proteins (HERCs) belong to the superfamily of ubiquitin ligases. HERC proteins are divided into two subfamilies, Large and Small HERCs. Despite their similarities in terms of both structure and domains, these subfamilies are evolutionarily very distant and result from a convergence phenomenon rather than from a common origin. Large HERC genes, HERC1 and HERC2, are present in most metazoan taxa. They encode very large proteins (approximately 5,000 amino acid residues in a single polypeptide chain) that contain more than one RCC1-like domain as a structural characteristic. Accumulating evidences show that these unusually large proteins play key roles in a wide range of cellular functions which include neurodevelopment, DNA damage repair, and cell proliferation. To better understand the origin, evolution, and function of the Large HERC family, this minireview provides with an integrated overview of their structure and function and details their physiological implications. This study also highlights and discusses how dysregulation of these proteins is associated with severe human diseases such as neurological disorders and cancer.

Genome-wide meta-analysis of copy number variations with alcohol dependence

Genetic association studies and meta-analyses of alcohol dependence (AD) have reported AD-associated single nucleotide polymorphisms (SNPs). These SNPs collectively account for a small portion of estimated heritability in AD. Recent genome-wide copy number variation (CNV) studies have identified CNVs associated with AD and substance dependence, suggesting that a portion of the missing heritability is explained by CNV. We applied PennCNV and QuantiSNP CNV calling algorithms to identify consensus CNVs in five AD cohorts of European and African origins. After rigorous quality control, genome-wide meta-analyses of CNVs were carried out in 3243 well-diagnosed AD cases and 2802 controls. We identified nine CNV regions, including a deletion in chromosome 5q21.3 with a suggestive association with AD (OR=2.15 (1.41-3.29) and P=3.8 × 10^-4) and eight nominally significant CNV regions. All regions were replicated with consistent effect sizes across studies and populations. Pathway and gene-drug interaction enrichment analyses based on the resulting genes indicated the mitogen-activated protein kinase signaling pathway and the recombinant insulin and hyaluronidase drugs, which were relevant to AD biology or treatment. To our knowledge, this is the first genome-wide meta-analysis of CNVs with addiction. Further investigation of the AD-associated CNV regions will provide better understanding of the AD genetic mechanism.

Not everything is blue or brown: Quantification of ocular coloration in psychological research beyond dichotomous categorizations

The notion that phenomenologically observable differences in the human eye are correlated with behavioral tendencies (other than gaze-following) has been addressed poorly in the psychological literature. Most notably, the proposed correlations are based on an arbitrary categorization in discrete categories of the continuous variability across various traits that could be contributing to individual eye morphologies. We review the relevant literature and assume a view of human eyes as sign stimuli, identifying the relative contrast between the iridal and scleral areas as the main contributor to the strength of the signal. Based on this view, we present a new method for the precise quantification of the relative luminosity of the iris (RLI) and briefly discuss its potential applications in psychological research.