The new trypanosomatid genetics

The recent development of transfection systems for trypanosomatids has removed a major obstacle to research and provides an important tool for the biochemist, immunologist and molecular biologist. Obtaining expression of a foreign gene in a trypanosomatid has been difficult. In this review, Vivian Bellofatto describes the problems and pitfalls of the process and final successes achieved.     

A new era of human population genetics

A growing resource of methicillin-resistant Staphylococcus aureus (MRSA) genomes uncovers intriguing phylogeographic and recombination patterns and highlights challenges in identifying the source of these phenomena.     

The genetics of human obesity

Obesity is an important cause of morbidity and mortality in developed countries, and is also becoming increasingly prevalent in the developing world. Although environmental factors are important, there is considerable evidence that genes also have a significant role in its pathogenesis. The identification of genes that are involved in monogenic, syndromic and polygenic obesity has greatly increased our knowledge of the mechanisms that underlie this condition. In the future, dissection of the complex genetic architecture of obesity will provide new avenues for treatment and prevention, and will increase our understanding of the regulation of energy balance in humans.     

The genetics of human fatness

Studies on the quantitative genetics of fatness are reviewed in the framework of the twin, adoption-cohabitation, and familial aggregation methodologies. Low to moderate heritability of adult static fatness is evident. Somewhat less than one-third of the variation appears ascribable to genetic causes. Genetic factors may play a greater role in childhood fatness, especially during adolescence. Comparison of studies is made difficult by many methodological shortcomings. These include a rarity of studies of adult first-degree relatives “adulthood being the period in which fatness has the greatest health consequences”, different criteria of body fatness among studies, a lack of a full variety of genetic and adoptive relationships, inadequate sample sizes “especially in twin studies”, and unreported precision of fatness variables. Fatness change in the life cycle and the anatomical placement of fat are important modifiers of the health effects of obesity. Yet the genetics of these characteristics are little understood. Innovative statistical methods and study designs including path analysis, the family set method, and families of monozygous twins need wider application to the genetics of human fatness.     

The genetics of human personality

Personality traits are the relatively enduring patterns of thoughts, feelings and behaviors that reflect the tendency to respond in certain ways under certain circumstances. Twin and family studies have showed that personality traits are moderately heritable, and can predict various lifetime outcomes, including psychopathology. The Research Domain Criteria characterizes psychiatric diseases as extremes of normal tendencies, including specific personality traits. This implies that heritable variation in personality traits, such as neuroticism, would share a common genetic basis with psychiatric diseases, such as major depressive disorder. Despite considerable efforts over the past several decades, the genetic variants that influence personality are only beginning to be identified. We review these recent and increasingly rapid developments, which focus on the assessment of personality via several commonly used personality questionnaires in healthy human subjects. Study designs covered include twin, linkage, candidate gene association studies, genome‐wide association studies and polygenic analyses. Findings from genetic studies of personality have furthered our understanding about the genetic etiology of personality, which, like neuropsychiatric diseases themselves, is highly polygenic. Polygenic analyses have showed genetic correlations between personality and psychopathology, confirming that genetic studies of personality can help to elucidate the etiology of several neuropsychiatric diseases.     

Population genetics: A new apportionment of human diversity

A worldwide survey of polymorphic molecular markers shows that the human population is genetically homogeneous, in close agreement with evidence from quite different genes and traits.     

The genetics of human drug response

The genetics of variable drug response appears to be a more tractable complex trait than common disease predisposition. This has implications for prioritizing research and for experimental design, and in particular argues for extensive use of candidate gene based approaches in pharmacogenetic association studies. Eventually, when whole genome scanning becomes feasible, it may be appropriate to consider weighting schemes that assign higher prior probabilities of variants in genes related to the mode of action of metabolism of medicines.     

The molecular genetics of early human life

Molecular Genetics of Early Human Development(Human Molecular Genetics series), edited by T. Strachan, S. Lindsay and D.I. Wilson, Bios Scientific Publishers, 1997. £65 (xiv+265 pages) ISBN 1 859960 31 6     

The genetics of neuroticism and human values

Human values and personality have been shown to share genetic variance in twin studies. However, there is a lack of evidence about the genetic components of this association. This study examined the interplay between genes, values and personality in the case of neuroticism, because polygenic scores were available for this personality trait. First, we replicated prior evidence of a positive association between the polygenic neuroticism score (PNS) and neuroticism. Second, we found that the PNS was significantly associated with the whole human value space in a sinusoidal waveform that was consistent with Schwartz's circular model of human values. These results suggest that it is useful to consider human values in the analyses of genetic contributions to personality traits. They also pave the way for an investigation of the biological mechanisms contributing to human value orientations.