Genetical control of amylose content in a diallel set of rice crosses

Models proposed by Gale and Pooni, Kumar and Khush are applied to study the inheritance of amylose content in a diallel set of crosses produced from seven elite inbred lines of indica rice representing all the major rice consuming regions of the world. In theory, the standard (Hayman's and Griffing's) analyses of diallel tables and the Wr/Vr relationship are found to apply even though the trait under investigation is expressed in a triploid state. It is further revealed that reciprocal effects can only be detected unambiguously in the F2 diallel and the additive and non-additive effects cannot be separated in the B1 and B2 diallels when they are analysed separately. Analysis of the experimental data reveals that additive and dominance effects are the main sources of variation among the 21 crosses of the 7 times 7 diallel. Comparisons of the B1 and B2 diallels also show that the single dosage dominance (ha1 type) effects differ significantly from the double dosage dominance (ha2 type) effects. In addition, cytoplasmic control of amylose content is confirmed unambiguously and a large proportion of the heritable variation is shown to be controlled by a series of multiple alleles with large effects

Genetical control of amylose content in selected crosses of indica rice

Models of Pooni et al. (1992) were employed to investigate the genetic control of amylose content in 10 rice crosses produced by the pairwise crossing of five varieties representing almost the whole range of amylose levels from 0 to 28 per cent. Analyses of the first-degree statistics revealed an important role of the additive and the dominance effects in determining the genetic variability in all the crosses. Epistasis and cytoplasmic effects were also observed to contribute significantly to the variability among the generation means of most crosses. Dominance was generally towards the higher score and its effects were enhanced by a complementary dominance x dominance interaction in several sets of basic generations. The predominantly additive nature of the genetic variability was further revealed by the analyses of second-degree statistics. Component D was detected significant in all the crosses while components H1 and H2 were non-significant throughout. Significance of the covariance components F' and F", however, showed indirectly that dominance contributed significantly to variability at the variance level. Higher levels of transgression and considerable increases in the phenotypic ranges displayed by the segregating generations of various crosses, also pointed to their potency for yielding superior recombinants with diverse levels of amylose

A comprehensive model for disomically inherited metrical traits expressed in triploid tissues

A biometrical genetic model is presented for the analysis of quantitatively varying diploid inherited traits which are expressed in a triploid phase. It shows that gene dispersion and ambidirectionality influences virtually all the components of means and at least four components of variances. Consequently, separate parameters are needed to describe the genetic variation among the second-degree statistics of the selfing and the backcrossing series. It is further shown that the effects of maternal/cytoplasmic inheritance can be separated from those of the nuclear genes both by the scaling tests and by the weighted least squares method. The applicability of the model to experimental data is demonstrated by analysing the amylose content of the generations derived from a cross between two pure breeding lines of rice

A general method of detecting additive, dominance and epistatic variation for metrical traits. V. Triple test cross analysis of disomically inherited traits expressed in triploid tissues

The applicability of the triple test cross design to the genetic analysis of metrical traits that subscribe to disomic inheritance but are expressed in a trisomie state has been investigated both theoretically and experimentally. Theory has shown that the standard sets of triple test cross families (L1i etc.) do not provide unambiguous tests of the additive, dominance and epistatic effects when reciprocal crosses are analysed separately. Analysis of the backcross families also suffers from similar problems but only in respect of the additive component and the tests of dominance and epistasis are not biased by the parentage of the families. Selfs of the standard families, on the other hand, do not display reciprocal differences (of heritable kind) and therefore provide umambiguous tests of the additive, dominance and epistatic effects, but the dominance component is now detected with reduced reliability as the level of heterozygosity is halved due to selfing. Theory further shows that biases of the various tests are eliminated rather easily by including the reciprocal families in the analysis. This is confirmed to a large extent by the analysis of amylose content in rice which also reveals that it is controlled by genes that display both interallelic (additive and dominance) and nonallelic interactions. Furthermore, dominance is shown to be partial but the dominance ratio seems to be high for both the ha1 and ha2 types of non-additive effects

Components of genetic variation in short-duration pigeonpea crosses under waterlogged conditions

Waterlogging inflicts considerable stress and yield-loss on short-duration pigeonpea and the present study investigates the genetical control of phenotypic variation expressed in the basic generations of some elite crosses under waterlogged conditions. Comparisons of the parental and Fl families for the 22 traits representing various facets of morphological variability revealed that the additive and dominance effects were present for a large number of these traits. Better parent heterosis was present in one or more crosses for all except two traits (ILN40 and NTR40) and a maximum of five (out of six) crosses showed heterosis for plant height (PH40) and days to lenticel formation (DYL). Analyses of the PI( P2, nents of genetic variation in short-duration pigeonpea crosses under waterlogged conditionsF1( F2, F3> Bcu and Bct^ generations further indicated that the genetical control of various traits was rather complex. Epistasis was detected for S6 (out of 126) cross/trajt combinations and there was no trait for which epistasis was non-significant in all the crosses. Presence of predominantly duplicate epistasis also pointed to a transient advantage for the hybrid varieties and better prospects of extracting superior recombinant inbred lines. In general, crosses between the tolerant and susceptible lines showed more variation compared to those involving only the tolerant lines and therefore possessed better potential for further breeding. Lack of apparent association between plant vigour and tolerance to waterlogging also indicated that plant vigour does not play a direct role in determining the tolerance to waterlogging in short-duration pigeonpea

Alexithymia may explain the relationship between autistic traits and eating disorder psychopathology

Background: Autistic people are disproportionately vulnerable to anorexia nervosa and other eating disorders (ED), and within the general population, autistic traits correlate with ED psychopathology. A putative mechanism which may underpin this heightened risk is alexithymia, a difficulty identifying and describing emotional states which is observed in both autism and ED. In two experiments with independent non-clinical samples, we explored whether alexithymia might mediate the heightened risk of eating psychopathology in individuals high in autistic traits. Methods: Our first experiment used the PROCESS macro for SPSS to examine relationships between alexithymia (measured by the Toronto Alexithymia Scale (TAS-20)), autistic traits (autism quotient (AQ)), and eating psychopathology (Eating Attitudes Test (EAT-26)) in 121 participants. Our second experiment (n = 300) replicated and furthered this analysis by examining moderating effects of sex and controlling for anxiety and depression as covariates. We also included an additional performance-based measure of alexithymia, the Levels of Emotional Awareness Scale (LEAS). Results: Study 1 suggested that TAS-20 scores mediated the relationship between heightened autistic traits and eating psychopathology. Replication and further scrutiny of this finding, in study 2, revealed that this mediation effect was partial and specific to the female participants in this sample. The mediation effect appeared to be carried by the difficulty identifying feelings subscale of the TAS-20, even when depression and anxiety were controlled for. LEAS scores, however, were not significantly related to autistic traits or eating psychopathology. Limitations: Cross-sectional data prevents any conclusions around the direction and causality of relationships between alexithymia, autistic traits, and eating psychopathology (alongside depression and anxiety), necessitating longitudinal research. Our non-clinical sample was predominantly Caucasian undergraduate students, so it remains to be seen if these results would extrapolate to clinical and/or autistic samples. Divergence between the TAS-20 and LEAS raises crucial questions regarding the construct validity of these measures. Conclusions: Our findings with respect to autistic traits suggest that alexithymia could partially explain the prevalence of ED in autistic people and may as such be an important consideration in the pathogenesis and treatment of ED in autistic and non-autistic people alike. Further research with clinical samples is critical to explore these ideas. Differences between men and women, furthermore, emphasize the importance of looking for sexspecific as well as generic risk factors in autistic and non-autistic men and women

Risk of adverse outcomes in patients with underlying respiratory conditions admitted to hospital with COVID-19:a national, multicentre prospective cohort study using the ISARIC WHO Clinical Characterisation Protocol UK

Background Studies of patients admitted to hospital with COVID-19 have found varying mortality outcomes associated with underlying respiratory conditions and inhaled corticosteroid use. Using data from a national, multicentre, prospective cohort, we aimed to characterise people with COVID-19 admitted to hospital with underlying respiratory disease, assess the level of care received, measure in-hospital mortality, and examine the effect of inhaled corticosteroid use. Methods We analysed data from the International Severe Acute Respiratory and emerging Infection Consortium (ISARIC) WHO Clinical Characterisation Protocol UK (CCP-UK) study. All patients admitted to hospital with COVID-19 across England, Scotland, and Wales between Jan 17 and Aug 3, 2020, were eligible for inclusion in this analysis. Patients with asthma, chronic pulmonary disease, or both, were identified and stratified by age (<16 years, 16–49 years, and ≥50 years). In-hospital mortality was measured by use of multilevel Cox proportional hazards, adjusting for demographics, comorbidities, and medications (inhaled corticosteroids, short-acting β-agonists [SABAs], and long-acting β-agonists [LABAs]). Patients with asthma who were taking an inhaled corticosteroid plus LABA plus another maintenance asthma medication were considered to have severe asthma. Findings 75 463 patients from 258 participating health-care facilities were included in this analysis: 860 patients younger than 16 years (74 [8·6%] with asthma), 8950 patients aged 16–49 years (1867 [20·9%] with asthma), and 65 653 patients aged 50 years and older (5918 [9·0%] with asthma, 10 266 [15·6%] with chronic pulmonary disease, and 2071 [3·2%] with both asthma and chronic pulmonary disease). Patients with asthma were significantly more likely than those without asthma to receive critical care (patients aged 16–49 years: adjusted odds ratio [OR] 1·20 [95% CI 1·05–1·37]; p=0·0080; patients aged ≥50 years: adjusted OR 1·17 [1·08–1·27]; p<0·0001), and patients aged 50 years and older with chronic pulmonary disease (with or without asthma) were significantly less likely than those without a respiratory condition to receive critical care (adjusted OR 0·66 [0·60–0·72] for those without asthma and 0·74 [0·62–0·87] for those with asthma; p<0·0001 for both). In patients aged 16–49 years, only those with severe asthma had a significant increase in mortality compared to those with no asthma (adjusted hazard ratio [HR] 1·17 [95% CI 0·73–1·86] for those on no asthma therapy, 0·99 [0·61–1·58] for those on SABAs only, 0·94 [0·62–1·43] for those on inhaled corticosteroids only, 1·02 [0·67–1·54] for those on inhaled corticosteroids plus LABAs, and 1·96 [1·25–3·08] for those with severe asthma). Among patients aged 50 years and older, those with chronic pulmonary disease had a significantly increased mortality risk, regardless of inhaled corticosteroid use, compared to patients without an underlying respiratory condition (adjusted HR 1·16 [95% CI 1·12–1·22] for those not on inhaled corticosteroids, and 1·10 [1·04–1·16] for those on inhaled corticosteroids; p<0·0001). Patients aged 50 years and older with severe asthma also had an increased mortality risk compared to those not on asthma therapy (adjusted HR 1·24 [95% CI 1·04–1·49]). In patients aged 50 years and older, inhaled corticosteroid use within 2 weeks of hospital admission was associated with decreased mortality in those with asthma, compared to those without an underlying respiratory condition (adjusted HR 0·86 [95% CI 0·80−0·92]). Interpretation Underlying respiratory conditions are common in patients admitted to hospital with COVID-19. Regardless of the severity of symptoms at admission and comorbidities, patients with asthma were more likely, and those with chronic pulmonary disease less likely, to receive critical care than patients without an underlying respiratory condition. In patients aged 16 years and older, severe asthma was associated with increased mortality compared to non-severe asthma. In patients aged 50 years and older, inhaled corticosteroid use in those with asthma was associated with lower mortality than in patients without an underlying respiratory condition; patients with chronic pulmonary disease had significantly increased mortality compared to those with no underlying respiratory condition, regardless of inhaled corticosteroid use. Our results suggest that the use of inhaled corticosteroids, within 2 weeks of admission, improves survival for patients aged 50 years and older with asthma, but not for those with chronic pulmonary disease