Sorghum is a food and feed cereal crop adapted to heat and drought and a staple for 500 million of the world’s poorest people. Its small diploid genome and phenotypic diversity make it an ideal C4 grass model as a complement to C3 rice. Here we present high coverage (16–45 × ) resequenced genomes of 44 sorghum lines representing the primary gene pool and spanning dimensions of geographic origin, end-use and taxonomic group. We also report the first resequenced genome of S. propinquum, identifying 8 M high-quality SNPs, 1.9 M indels and specific gene loss and gain events in S. bicolor. We observe strong racial structure and a complex domestication history involving at least two distinct domestication events. These assembled genomes enable the leveraging of existing cereal functional genomics data against the novel diversity available in sorghum, providing an unmatched resource for the genetic improvement of sorghum and other grass species.

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We describe the development and application of the Sorghum QTL Atlas, a high-resolution, open-access research platform to facilitate candidate gene identification across three cereal species, sorghum, maize and rice. Abstract The mechanisms governing the genetic control of many quantitative traits are only poorly understood and have yet to be fully exploited. Over the last two decades, over a thousand QTL and GWAS studies have been published in the major cereal crops including sorghum, maize and rice. A large body of information has been generated on the genetic basis of quantitative traits, their genomic location, allelic effects and epistatic interactions. However, such QTL information has not been widely applied by cereal improvement programs and genetic researchers worldwide. In part this is due to the heterogeneous nature of QTL studies which leads QTL reliability variation from study to study. Using approaches to adjust the QTL confidence interval, this platform provides access to the most updated sorghum QTL information than any database available, spanning 23 years of research since 1995. The QTL database provides information on the predicted gene models underlying the QTL CI, across all sorghum genome assembly gene sets and maize and rice genome assemblies and also provides information on the diversity of the underlying genes and information on signatures of selection in sorghum. The resulting high-resolution, open-access research platform facilitates candidate gene identification across 3 cereal species, sorghum, maize and rice. Using a number of trait examples, we demonstrate the power and resolution of the resource to facilitate comparative genomics approaches to provide a bridge between genomics and applied breeding.

This article presents the proceedings of a symposium held at the meeting of the International Society for Biomedical Research on Alcoholism (ISBRA) in Mannheim, Germany, in October, 2004. Chronic alcoholism follows a fluctuating course, which provides a naturalistic experiment in vulnerability, resilience, and recovery of human neural systems in response to presence, absence, and history of the neurotoxic effects of alcoholism. Alcohol dependence is a progressive chronic disease that is associated with changes in neuroanatomy, neurophysiology, neural gene expression, psychology, and behavior. Specifically, alcohol dependence is characterized by a neuropsychological profile of mild to moderate impairment in executive functions, visuospatial abilities, and postural stability, together with relative sparing of declarative memory, language skills, and primary motor and perceptual abilities. Recovery from alcoholism is associated with a partial reversal of CNS deficits that occur in alcoholism. The reversal of deficits during recovery from alcoholism indicates that brain structure is capable of repair and restructuring in response to insult in adulthood. Indirect support of this repair model derives from studies of selective neuropsychological processes, structural and functional neuroimaging studies, and preclinical studies on degeneration and regeneration during the development of alcohol dependence and recovery form dependence. Genetics and brain regional specificity contribute to unique changes in neuropsychology and neuroanatomy in alcoholism and recovery. This symposium includes state-of-the-art presentations on changes that occur during active alcoholism as well as those that may occur during recovery-abstinence from alcohol dependence. Included are human neuroimaging and neuropsychological assessments, changes in human brain gene expression, allelic combinations of genes associated with alcohol dependence and preclinical studies investigating mechanisms of alcohol induced neurotoxicity, and neuroprogenetor cell expansion during recovery from alcohol dependence.

Duphniu (Crustacea: Cladocera) reproduce by cyclical parthenogenesis in which the sex of offspring is environmentally determined. Although numerous studies have demonstrated that factors such as crowding and short-day photoperiod stimulate male production, there is limited information on variation in allocation to male and female offspring for any species of Duphniu. The present study assessed the presence or absence of male production in 96 isofemale lines (clones) from each of eight populations of Duphniu pulex. An average of 37% (range l&51%) of clones failed to produce males under crowded conditions in the laboratory. A subset of 14 of these non-male-producing clones also failed to produce males under short-day photoperiod (8L: 16D). Three male-producing clones were within-clone mated as well as crossed to three non-male-producing clones to study the inheritance of the failure to produce males. The average frequency of non-male-producing F, progeny was significantly higher (58%, N = 486) among the outcrossed progeny than the inbred progeny (5%, N = 86). In addition, when sixteen of the male-producing outcrossed progeny were withinclone mated, only 7% (N = 106) of the resulting F, progeny failed to produce males. These results are consistent with a genetic basis for the absence of male production. Average survival of the progeny from the nine outcrossed matings was more than twice (67%) that of the inbred progeny from the three withinclone matings (30%) suggesting that within-clone mating would result in significant inbreeding depression. We present a model that suggests that even low levels of inbreeding could allow non-male-producing females to be maintained in a population. The co-occurrence of non-male-producing females and females that produce both males and females in Duphniu p&x bears a similarity to the gynodioecious breeding system found in some plant species. 560Innes and Dunbrack

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A survey of nine ponds in Illinois and Iowa confirmed the occurrence of both cyclically and obligately parthenogenetic D. pulex and cyclically parthenogenetic D. obtusa. The three taxa co-occurred in two of the ponds and one predominantly cyclical parthenogenetic population of D. pulex also contained an obligately parthenogenetic clone. Three populations consisted solely of obligately parthenogenetic D. pulex, whilç three consisted solely of cyclically parthenogenetic D. obtusa. Populations of cyclically parthenogenetic individuals, which have a sexual phase, were usually in Hardy-Weinberg equilibrium at individual loci and had a high genotypic diversity. Populations of obligately parthenogenetic individuals deviated from Hardy-Weinberg equilibrium and often consisted of only one or two clones. Mode of reproduction was confirmed by breeding studies on individuals isolated from the populations. Daphnia pulex and D. obtusa were genetically distinct based on variation at six polymorphic loci. Individuals of D. pulex reproducing by the two modes of reproduction were also genetically differentiated. Obligately parthenogenetic individuals wereLdh 13 and Pep 12 heterozygotes while cyclically parthenogenetic individuals were 11 homozygotes at both loci. Seven obligately parthenogenetic clones were found with only one clone occurring in more than one population. The high genotypic diversity and restricted distribution of obligately parthenogenetic clones is consistent with their independent origin from cyclically parthenogenetic individuals.