Seeds and seasons: interpreting germination timing in the field

2005 ◽  
Vol 15 (3) ◽  
pp. 175-187 ◽  
Author(s):  
Kathleen Donohue
Keyword(s):  
Environmental Factors ◽  
Genetic Basis ◽  
Genetic Material ◽  
Field Studies ◽  
Seed Maturation ◽  
Genetic Pathways ◽  
Ecological Conditions ◽  
Germination Phenology ◽  
Transgenic Lines ◽  
Germination Timing

This paper discusses how field and laboratory experiments, using a variety of genetic material, can be combined to investigate the genetic basis of germination under realistic ecological conditions, and it reviews some of our recent work on germination phenology ofArabidopsis thalianain the field. Our results indicate that the genetic basis of germination depends on the environment. In particular, the conditions during seed maturation interact with post-dispersal environmental factors to determine germination phenology, and these interactions have a genetic basis. Therefore genetic studies of germination need to consider carefully the environment – both during seed maturation and after dispersal – in which the experiments are conducted in order to characterize genetic pathways involved with germination in the field. Laboratory studies that explicitly manipulate ecologically relevant environmental factors can be combined with manipulative field studies. These studies can identify the particular environmental cues to which seeds respond in the field and characterize the genetic basis of germination responses to those cues. In addition, a variety of genetic material – including mutant and transgenic lines, intact natural genotypes, recombinant genotypes, and near isogenic lines – can be used in field studies as tools to characterize genetic pathways involved in germination schedules under natural ecological conditions.

scholarly journals The Molecular-Genetic Basis of Functional Hyperandrogenism and the Polycystic Ovary Syndrome

2005 ◽  
Vol 26 (2) ◽  
pp. 251-282 ◽  
Author(s):  
Héctor F. Escobar-Morreale ◽  
Manuel Luque-Ramírez ◽  
José L. San Millán
Keyword(s):  
Environmental Factors ◽  
Polycystic Ovary Syndrome ◽  
Diagnostic Criteria ◽  
Genetic Basis ◽  
Polycystic Ovary ◽  
Molecular Genetic ◽  
Ovary Syndrome ◽  
The Metabolic Syndrome ◽  
Molecular Genetic Basis ◽  
Functional Hyperandrogenism

The genetic mechanisms underlying functional hyperandrogenism and the polycystic ovary syndrome (PCOS) remain largely unknown. Given the large number of genetic variants found in association with these disorders, the emerging picture is that of a complex multigenic trait in which environmental influences play an important role in the expression of the hyperandrogenic phenotype. Among others, genomic variants in genes related to the regulation of androgen biosynthesis and function, insulin resistance, and the metabolic syndrome, and proinflammatory genotypes may be involved in the genetic predisposition to functional hyperandrogenism and PCOS. The elucidation of the molecular genetic basis of these disorders has been burdened by the heterogeneity in the diagnostic criteria used to define PCOS, the limited sample size of the studies conducted to date, and the lack of precision in the identification of ethnic and environmental factors that trigger the development of hyperandrogenic disorders. Progress in this area requires adequately sized multicenter collaborative studies after standardization of the diagnostic criteria used to classify hyperandrogenic patients, in whom modifying environmental factors such as ethnicity, diet, and lifestyle are identified with precision. In addition to classic molecular genetic techniques such as linkage analysis in the form of a whole-genome scan and large case-control studies, promising genomic and proteomic approaches will be paramount to our understanding of the pathogenesis of functional hyperandrogenism and PCOS, allowing a more precise prevention, diagnosis, and treatment of these prevalent disorders.

scholarly journals Schizophrenia and Its Genetic Basis: A Review Study

2017 ◽  
Vol 4 (2) ◽  
Author(s):  
Somayeh Maleki ◽  
Mohammad Ali Taheri
Keyword(s):  
Mental Illness ◽  
Research Method ◽  
Genetic Basis ◽  
Psychotic Disorders ◽  
Field Studies ◽  
Effective Index ◽  
Preventive Interventions ◽  
Occupational Functioning ◽  
Review Study

Background: Schizophrenia is a devastating mental illness that interferes with the patient’s social and occupational functioning and impairs the patient’s life. Methods: The research method is a Review Study based on library, documentary and field studies. Results: Studies indicate the bio-genetic basis in the etiology of schizophrenia disorder; however, the mystery of the formation of this disease is still somewhat unknown. Parents’ age is considered as an effective index on incidence of children to psychotic disorders. Studies show that parents’ higher age is associated with having children with schizophrenia and mostly parents, who have children with schizophrenia under the legal age, do not live with their child. Conclusion: This study was a review study, the results of which can be useful in planning preventive interventions.

REACTION OF SPRING WHEAT LINES WITH FOREIGN GENETIC MATERIAL TO THE IMPACT OF ARTIFICIALLY CREATED STRESSES

2021 ◽  
Author(s):  
O. V. Pavlova ◽  
◽  
L. A. Marchenkova ◽  
R. F. Chavdar ◽  
T. G. Orlova ◽  
...  
Keyword(s):  
Sodium Chloride ◽  
Environmental Factors ◽  
Spring Wheat ◽  
Genetic Material ◽  
Growth Processes ◽  
Genetic Characteristics ◽  
Early Stages ◽  
Inhibition Of Growth ◽  
Wheat Lines ◽  
The Impact

The adaptive properties of spring wheat lines with foreign genetic material at the early stages of ontogenesis on the backgrounds of salinization with sodium chloride and prolonged flooding of seeds in water were evaluated. In the course of the work, different degrees of inhibition of growth processes were revealed, depending on the factor used and the genetic characteristics of the studied forms, a comprehensive (summary) assessment of the index of stability characterizing adaptability to adverse environmental factors was shown.

scholarly journals The ecology of shell shape difference in chirally dimorphic snails

2012 ◽  
Vol 81 (2) ◽  
pp. 95-101 ◽  
Author(s):  
Menno Schilthuizen ◽  
Martin Haase ◽  
Kees Koops ◽  
Sylvia M. Looijestijn ◽  
Sigrid Hendrikse
Keyword(s):  
Sexual Selection ◽  
Environmental Factors ◽  
Field Studies ◽  
Southeast Asian ◽  
Predation Pressure ◽  
Shell Shape ◽  
Ecological Traits ◽  
Shape Difference ◽  
Environmental Selection

The Southeast-Asian tree snail subgenus Amphidromus s. str. (Gastropoda Pulmonata: Camaenidae) is unusual among all gastropods for its genetic antisymmetry: populations consist of stable mixtures of individuals with clockwise (dextral) and counterclockwise (sinistral) coiling directions. Although previous studies in A. inversus suggest that this genetic dimorphism is maintained by sexual selection, it cannot be ruled out that environmental factors also play a role. Adult shell shapes in A. inversus are known to show subtle differences between both coiling morphs, and it is known that in snails in general, shell shape is under environmental selection, thus creating the possibility that micro-niche use of both coiling morphs differs. In this paper, we first confirm that hatchlings also differ in shell shape. We then proceed with field studies to compare dextral and sinistral juveniles and adults for (i) direction and rate of dispersal within the vegetation and (ii) micro-niche occupation. However, we failed to detect any difference in both ecological traits. In addition to earlier data that show that there is no clustering of morphs in the field and that both morphs suffer identical predation pressure, these new data do not provide any evidence for a role for environmental factors in maintaining the coil dimorphism in this species.

scholarly journals The genetics of isolated and syndromic clubfoot

2019 ◽  
Vol 13 (3) ◽  
pp. 238-244 ◽  
Author(s):  
B. Sadler ◽  
C. A. Gurnett ◽  
M. B. Dobbs
Keyword(s):  
Transforming Growth Factor Beta ◽  
Genetic Screening ◽  
Genetic Basis ◽  
Transforming Growth Factor ◽  
Matrix Proteins ◽  
Congenital Clubfoot ◽  
Level Of Evidence ◽  
Genetic Pathways ◽  
Growth Factor Beta ◽  
Underlying Pathophysiology

Purpose Congenital clubfoot is a serious birth defect that affects nearly 0.1% of all births. Though there is strong evidence for a genetic basis of isolated clubfoot, aside from a handful of associations, much of the heritability remains unexplained. Methods By systematically examining the genes involved in syndromic clubfoot, we may find new candidate genes and pathways to investigate in isolated clubfoot. Results In addition to the expected enrichment of extracellular matrix and transforming growth factor beta (TGF-β) signalling genes, we find many genes involved in syndromic clubfoot encode peroxisomal matrix proteins, as well as enzymes necessary for sulfation of proteoglycans, an important part of connective tissue. Further, the association of Filamin B with isolated clubfoot as well as syndromic clubfoot is an encouraging finding. Conclusion We should examine these categories for enrichment in isolated clubfoot patients to increase our understanding of the underlying biology and pathophysiology of this deformity. Understanding the spectrum of syndromes that have clubfoot as a feature enables a better understanding of the underlying pathophysiology of the disorder and directs future genetic screening efforts toward certain genes and genetic pathways. Level of evidence V

Genetic basis for the determination of sex

1970 ◽  
Vol 259 (828) ◽  
pp. 3-14 ◽  
Keyword(s):  
Sex Ratio ◽  
Genetic Basis ◽  
Sex Differentiation ◽  
Genetic Material ◽  
Selective Advantage ◽  
Mature Spermatozoon ◽  
General Question ◽  
Parental Expenditure ◽  
General Aspects

An introductory review is given of some general aspects of the genetic basis for the determination of sex, with particular reference to vertebrates. The Weismann-Fisher view is that sex arose because it was of selective advantage. The bisexuality of vertebrates is not necessarily ‘best’ for the group in terms of selective advantage; however, the very simplicity of the bisexual system may have been advantageous. The common near-equality in the numbers of the sexes is explained by the Darwin-Fisher ‘ automatic 1:1 tendency’, and Fisher’s concept of parental expenditure can explain deviations from equality and also changes in the ratio during embryogenesis. A direct selective advantage can be argued for the 1:1 ratio—or, more generally, for that ratio which maximizes the chance of a successful encounter of the sexes. Possible modes of gene action affecting sex ratio are discussed. A new assessment is made of the identity of the heterogametic and homogametic sexes in vertebrates, the conclusions for Amphibia deviating from those in some of the literature. It is maintained for vertebrates in general that the ‘ odd ’ sex chromosomes (Y or W) of a species determine strongly in the direction of one gonadal sex. Responsibility for determining the opposite sex must lie between the autosomes and the ‘ even ’ chromosomes (X or Z), but there is little evidence that the ‘even’ chromosomes are specifically implicated. Sex differentiation may not be controlled by a limited number of sex-determining genes, and the ultimate units may be aggregates of the genetic material larger than genes. The possibility of controlling sex ratio at conception by altering the proportion in which X- and Y-bearing spermatozoa fertilize eggs is discussed in relation to the more general question of whether the phenotype of a developing or mature spermatozoon can be affected by its own haploid genetic content.

Some like it cool? Intermorph comparison of preferred body temperature in a colour-dimorphic snake

2009 ◽  
Vol 59 (1) ◽  
pp. 31-39 ◽  
Author(s):  
Koji Tanaka
Keyword(s):  
Body Temperature ◽  
Environmental Factors ◽  
Laboratory Experiment ◽  
Predation Risk ◽  
Field Studies ◽  
Behavioural Thermoregulation ◽  
Model Species ◽  
High Predation ◽  
Preferred Body Temperature ◽  
Recent Laboratory

AbstractOrganismal characteristics of ectotherms are profoundly affected by body temperature (Tb). Despite constraints imposed by environmental factors, they can adjust Tb by several means. However, if thermoregulatory ability is limited by their own property such as coloration and this constraint affects individual's fitness, selection may promote coevolution of coloration and thermal aspects. I investigated this topic using a colour-dimorphic (melanistic/striped) snake Elaphe quadrivirgata as a model species. Recent laboratory experiment revealed slower body warming in striped individuals than in melanistic individuals. Under this circumstance, one way that striped individuals can manage their slower body warming is to prefer low Tb. Contrary to this prediction, there was no intermorph difference in preferred Tb. Coupled with the results of field studies, I suggest that striped individuals manage their slower body warming by behavioural thermoregulation and that constraints (e.g., high predation risk due to conspicuousness under thermally superior habitats) imposed on melanistic individuals lessen their thermal advantages. The effect of melanism on thermal aspects may not be so advantageous for melanistic animals than generally thought.

scholarly journals Variation in hip and sepal parameters of invasive Rosa rugosa between sites and years

Botanica ◽  
2021 ◽  
pp. 1-12
Author(s):  
Zigmantas Gudžinskas ◽  
Mindaugas Rasimavičius
Keyword(s):  
Invasive Species ◽  
Environmental Factors ◽  
Sunshine Duration ◽  
Negative Relationship ◽  
Cumulative Effect ◽  
Field Studies ◽  
Width Ratio ◽  
Coastal Habitat ◽  
Rosa Rugosa ◽  
Sepal Length

Rosa rugosa is among the most invasive species in Europe, and it is considered a severe threat to the diversity and stability of coastal habitats. In Lithuania, it is a widespread invasive species occurring in coastal and inland areas. This research aimed to estimate the variation in R. rugosa hip and sepal parameters within and among sites from coastal and inland areas, and investigate the effects of environmental factors on the hip and sepal sizes. Field studies were performed at four coastal and three inland sites in 2008, and the studies were repeated in 2016. We collected 100 mature hips at each site and measured the hip width, hip length and sepal length. We analysed variation in hip and sepal parameters between the study years, and the effect of meteorological factors and agrochemical properties of the soil on hip and sepal sizes. This study revealed significant variation in R. rugosa hip width, hip length and sepal length among the studied sites. The largest hips and sepals were found in the coastal habitat at the Smeltė site, whereas the smallest hips and sepals were recorded in inland habitat at the Staviškės site, where R. rugosa occurred in woodland. The comparison of hip and sepal sizes at the same sites during two study years revealed irregular variation. Mean hip width and mean length of sepals in 2008 were significantly more prominent than in 2016, whereas no significant differences in hip length were found between the study years. The content of phosphorus in the soil negatively correlated, whereas the content of carbonates positively correlated with the sepal length. A strong negative relationship was found between the sunshine duration and hip length and width ratio. However, the revealed relationships of the hip and sepal parameters with the environmental factors could be a coincidence or a result of the cumulative effect of the multiple factors’ interaction and should be investigated separately.

scholarly journals Combining Natural and Engineered Host Plant Resistance Mechanisms in Potato for Colorado Potato Beetle: Choice and No-choice Field Studies

2005 ◽  
Vol 130 (6) ◽  
pp. 857-864 ◽  
Author(s):  
Joseph J. Coombs ◽  
David S. Douches ◽  
Susannah G. Cooper ◽  
Edward J. Grafius ◽  
Walter L. Pett ◽  
...  
Keyword(s):  
Host Plant ◽  
Plant Resistance ◽  
Colorado Potato Beetle ◽  
Host Plant Resistance ◽  
Glandular Trichomes ◽  
Field Studies ◽  
Resistance Mechanisms ◽  
Field Cage ◽  
Potato Beetle ◽  
Transgenic Lines

Colorado potato beetle (Leptinotarsa decemlineata Say) is the leading insect pest of potato (Solanum tuberosum L.) in northern latitudes. Host plant resistance is an important tool in an integrated pest management program for controlling insect pests. Field studies were conducted to compare natural host plant resistance mechanisms (glandular trichomes and Solanum chacoense Bitter-derived resistance), engineered [Bacillus thuringiensis (Bt) Berliner Bt-cry3A], and combined (glandular trichomes + Bt-cry3A and S. chacoense-derived resistance + Bt-cry3A transgenic potato lines) sources of resistance for control of colorado potato beetle. Six different potato clones representing five different host plant resistance mechanisms were evaluated for 2 years in a field situation under natural colorado potato beetle pressure in Michigan and New York, and in a no-choice field cage study in Michigan. In the field studies, the S. chacoense-derived resistance line, Bt-cry3A transgenic, and combined resistance lines were effective in controlling defoliation by colorado potato beetle adults and larvae. Effectively no feeding was observed in the Bt-cry3A transgenic lines. The glandular trichome line suffered less defoliation than the susceptible control, but had greater defoliation than the Bt-cry3A transgenic lines and the S. chacoense-derived resistance line. In the no-choice cage study, the Bt-cry3A transgenic lines and the combined resistance lines were effective in controlling feeding by colorado potato beetle adults and larvae with no defoliation observed. The S. chacoense-derived resistance line and the glandular trichome line suffered less defoliation than the susceptible control. Based on the results of the field trials and no-choice field cage studies, these host plant resistance mechanisms could be used to develop potato varieties for use in a resistance management program for control of colorado potato beetle.

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