Integrative Studies (integrative + studies)

Distribution by Scientific Domains

Selected Abstracts


EVOLUTION, Issue 9 2010
Jay F. Storz
Inferences about adaptation at specific loci are often exclusively based on the static analysis of DNA sequence variation. Ideally, population-genetic evidence for positive selection serves as a stepping-off point for experimental studies to elucidate the functional significance of the putatively adaptive variation. We argue that inferences about adaptation at specific loci are best achieved by integrating the indirect, retrospective insights provided by population-genetic analyses with the more direct, mechanistic insights provided by functional experiments. Integrative studies of adaptive genetic variation may sometimes be motivated by experimental insights into molecular function, which then provide the impetus to perform population genetic tests to evaluate whether the functional variation is of adaptive significance. In other cases, studies may be initiated by genome scans of DNA variation to identify candidate loci for recent adaptation. Results of such analyses can then motivate experimental efforts to test whether the identified candidate loci do in fact contribute to functional variation in some fitness-related phenotype. Functional studies can provide corroborative evidence for positive selection at particular loci, and can potentially reveal specific molecular mechanisms of adaptation. [source]

Mate Choice for Genetic Benefits: Time to Put the Pieces Together

ETHOLOGY, Issue 1 2010
Attila Hettyey
It is thought that mate choice allows individuals to obtain genetic benefits for their offspring, and although many studies have found some support for this hypothesis, several critical questions remain unresolved. One main problem is that empirical studies on mate choice and genetic benefits have been rather piecemeal. Some studies (1) aimed to test how mate choice affects offspring fitness, but have not examined whether the benefits are because of genetic effects. Other studies tested whether mate choice provides (2) additive or (3) non-additive genetic benefits and only a few studies (4) considered these genetic effects together. Finally, some studies (5) examined whether the potential benefits that might be gained from mate choice are due to additive genetic effects vs. non-additive effects, and although they found evidence for both, they did not examine whether mate choice is relevant. Furthermore, previous studies have usually not controlled for non-genetic sources of variation in offspring fitness. Thus, there remain gaping holes in our understanding, and it is the connections among the research approaches that now need more attention. We suggest that studies are needed that measure non-genetic effects, the potential benefits from both additive and non-additive genetic effects, and also determine whether mate choice exploits these potential benefits. Such integrative studies are necessary to put the pieces together and clarify the role of genetic benefits in the evolution of mate choice. [source]

Pigmentation development in hatchery-reared flatfishes

J. A. Bolker
Malpigmentation is common in hatchery-reared flatfishes, decreasing the market value of whole fish, and increasing the risk of predation for juveniles released to enhance wild stocks. Pigmentation development in flatfishes occurs in two phases. First, during embryonic and larval stages pigment cells differentiate on both sides of the body. Second, at metamorphosis larval melanophores disappear, and adult melanophores differentiate on the ocular but not on the blind side. Malpigmentation seems to result from disruptions of the second phase, and may take the form of albinism on the ocular side or darkening of the blind side. Both types of aberration may be related to aspects of the hatchery environment such as lighting, substratum, and diet. Larval nutrition appears to be a key factor and enrichment of larval diets with fatty acids and Vitamin A can greatly reduce malpigmentation rates; however, levels suffcient to prevent pigmentation defects frequently cause other abnormalities. Two developmental explanations for albinism have been proposed. The first is that differentiation of ocular-side skin follows the normal blind-side pathway and adult melanophores therefore fail to develop on the ocular side. The second hypothesis suggests that dietary deficiencies inhibit retinal development and the resulting visual defects lead to failure of a hormonal signal required for melanophore differentiation. These hypotheses may well be complementary; as yet neither has been thoroughly tested. Definitive tests will require a combination of manipulative techniques such as tissue transplantation and cell culture with nutritional, behavioural and hormonal assays. Such integrative studies will further the understanding both of normal pigmentation development and of the environmental factors that contribute to high rates of albinism in hatchery-reared flatfish. [source]

End-stage renal disease , not an equal opportunity disease: the role of genetic polymorphisms

Abstract. Despite several decades of development in renal replacement therapy, end-stage renal disease (ESRD) patients continue to have markedly increased morbidity and mortality especially caused by cardiovascular disease (CVD). This shows that current strategies, e.g. the focus on dialysis adequacy, to improve the clinical outcome in ESRD patients have to be complemented by novel approaches. Although traditional risk factors are common in dialysis patients they cannot alone explain the unacceptably high prevalence of CVD in this patient group. Much recent interest has therefore focused on the role of various nontraditional cardiovascular risk factors, such as inflammation, vascular calcification and oxidative stress. Recent studies show that genetic factors, such as DNA single nucleotide polymorphisms, may significantly influence the immune response, the levels of inflammatory markers, as well as the prevalence of atherosclerosis in this patient group. To elucidate the respective roles of DNA polymorphisms in genes that encode inflammatory markers (such as IL-10, IL-6 and TNF- ,) and other factors that may affect the development of atherosclerosis (such as apolipoprotein E, transforming growth factor and fetuin-A), sufficiently powered studies are needed in which genotype, the protein product and the specific phenotype all are analysed in relation to outcome. The recent developments in the field of genetics have opened up entirely new possibilities to understand the impact of genotype on disease development and progress and thus offer new options and strategies for treatment. It seems conceivable that in the near future, prognostic or predictive multigene DNA assays will provide the nephrological community with a more precise approach for the identification of ,high-risk' ESRD patients and the development of accurate individual treatment strategies. For this purpose, integrative studies on genotype,phenotype associations and impact on clinical outcome are needed. [source]