Half Siblings Research Articles

O-219 Donor conception and Commercial Genomics: how are donor conceived people, their parents and donors using direct-to-consumer genetic testing?

Abstract Study question How do donor conceived people, their parents and donors use direct-to-consumer genetic testing (DTCGT)? Summary answer DTCGT is changing how information about donor conception is accessed and managed by parents, donors and donor conceived people. What is known already Following the development and rapid expansion of DTCGT, there have been claims that ‘anonymity is dead’ in relation to donor conception (Darroch & Smith, 2021; Harper et al., 2016). Small-scale studies (Crawshaw, 2018) and media articles have reported that donor conceived adults are often finding out about the circumstances of their conception after using DCTGT. However, there is a gap in the evidence about how donor conceived people already aware of their donor conception, as well as parents through donor conception and donors, are using DTCGT. Study design, size, duration The ConnecteDNA project is an ongoing qualitative research study (March 2021-February 2024). It investigates how people in the UK, involved in donor conception, are impacted by DTCGT and considers the implications for policy and practice. This presentation focusses on phase two of the project: in-depth interviews with parents through donor conception, donors and donor conceived adults who have used, or considered using, DTCGT. Participants/materials, setting, methods So far, six donors, 13 parents through donor conception and 18 donor conceived adults have been interviewed via telephone or video call. Interviews are ongoing until September 2022. Participants were recruited by advertising the project via a range of support groups and organisations for donor conception and/or DTCGT user communities. Main results and the role of chance Our findings show that people involved in UK donor conception are using DCTGT to access and manage information about donor conception. This includes donor conceived people, previously unaware of the circumstances of their conception, discovering they are donor conceived after using DTCGT. We have found that donor conceived people, already aware that they are donor conceived, may also use DTCGT in search of information about ‘donor relatives’ and/or their genetic make-up, including understandings of their ethnicity and health risks. Furthermore, some donors are using DTCGT to make themselves contactable to people conceived via their donation(s), whilst others are traced via relatives who have used DTCGT. Parents through donor conception may use, or consider using DTCGT, to trace people related to their children through donor conception. This may be done when the child is very young, with the intention of finding relatives (particularly half siblings) who they can then grow up with. Others take a more responsive approach, only using DTCGT to support a child’s request or interest in more information. DTCGT is also used to trace genetic relatives alongside, or instead of, ‘official’ routes for accessing information about donor conception, as well as social media and public records. Limitations, reasons for caution Participants in this study are self-selecting and some groups may be under-represented in our sample (e.g. fathers through donor conception). We make no claims regarding the relative prevalence of different views and experiences. However, findings demonstrate the range of ways in which people involved in donor conception are using DTCGT. Wider implications of the findings DTCGT is transforming how people involved in donor conception seek information about genetic relatives. UK law and HFEA policies will require reform to account for this. Professionals who work with people using, or considering, donor conception, should make their clients aware of the potential uses and outcomes of DTCGT. Trial registration number Not applicable

Forensic Feature Exploration and Comprehensive Genetic Insights Into Yugu Ethnic Minority and Northern Han Population via a Novel NGS-Based Marker Set.

The MPS technology has expanded the potential applications of DNA markers and increased the discrimination power of the targeted loci by taking variations in their flanking regions into consideration. Here, a collection of nuclear and extranuclear DNA markers (totally six kinds of nuclear genetic markers and mtDNA hypervariable region variations) were comprehensively and systematically assessed for polymorphism detections, further employed to dissect the population backgrounds in the Yugu ethnic group from Gansu province (Yugu) and Han population from the Inner Mongolia Autonomous Region (NMH) of China. The elevated efficiencies of the marker set in separating full sibling and challenging half sibling determination cases in parentage tests (iiSNPs), as well as predicting ancestry origins of unknown individuals from at least four continental populations (aiSNPs) and providing informative characteristic-related clues for Chinese populations (piSNPs) are highlighted in the present study. To sum up, different sets of DNA markers revealed sufficient effciencies to serve as promising tools in forensic applications. Genetic insights from the perspectives of autosomal DNA, Y chromosomal DNA, and mtDNA variations yielded that the Yugu ethnic group was genetically close related to the Han populations of the northern region. But we admit that more reference populations (like Mongolian, Tibetan, Hui, and Tu) should be incorporated to gain a refined genetic background landscape of the Yugu group in future studies.

The causal effect of education and cognitive performance on risk for suicide attempt: A combined instrumental variable and co-relative approach in a Swedish national cohort

BackgroundThe aim of this study was to clarify the possible causal associations between education phenotypes and non-fatal suicide attempts. In particular, we evaluated the roles of academic achievement (school grades), cognitive performance (IQ), and educational attainment (education level). MethodsBased on longitudinal Swedish registry data, we included 2,335,763 individuals (48.7% female) with available school grades, 1,448,438 men with IQ measures, and 4,352,989 individuals (48.4% female) with available data on education level. We combined two different approaches to aid in causal inference: 1) instrumental variables analysis, using month of birth as an instrument related to education but not suicide attempt, to control for measured and unmeasured confounders, and 2) co-relative analysis, comparing pairs of different genetic relatedness (cousins, half, and full siblings) to control for genetic and environmental influences. ResultsHigh education was associated with reduced risk of suicide attempt. Instrumental variable analysis indicated evidence of a likely causal association between higher school grades and lower risk of suicide attempts (HR = 0.71). Co-relative analyses supported the causality between the three predictors and suicide attempt risk (school grades, HR = 0.80, IQ, HR = 0.83, education level, HR = 0.76). Finally, we examined the specificity of education phenotypes and found that both cognitive (IQ) and non-cognitive (school grades, education level) processes were involved in suicide attempt risk. LimitationsIQ was only available in men, limiting the generalizability of this analysis in women. ConclusionsEfforts to support causal associations in psychiatric research are needed to offer better intervention. Programs improving education during adolescence would decrease suicide attempt risk.

Sociological Accounts of Donor Siblings' Experiences: Their Importance for Self-Identity and New Kinship Relations.

A fundamental part of the adolescent self is formed through interaction with intimates, usually family members whose roles are reasonably well-defined. However, donor siblings—children who share a sperm donor—lack social scripts for interacting with one another, particularly when they are raised in different households. Moreover, they are often challenged to figure out their relationship to newly discovered genetic relatives. This article examines how donor-conceived teens and young adults navigate relationships with their half siblings and form intimate relationships. Drawing on Garfinkel’s concept of indexing, or the use of familiar categories to make sense of new situations, these youth rely upon their personal knowledge of friends and family to figure out what kinds of relationship they can develop with donor siblings. Based on interviews with 62 youth aged 14–28, who had their own social media accounts and who had chosen to establish contact with their donor siblings, the articles discusses the three stages most donor siblings go through—“anticipation”, “first contact”, and “relationship building”—and the way those stages shape individual identity formation. In the course of the analysis, the article also explores whether interaction with donor siblings affected individual’s sense of identity and whether feelings of closeness with donor siblings differ for youth raised as solo children versus those who have siblings with whom they share a household. For those who report feeling close, youth describe how intimacy is sustained and negotiated at a distance. Finally, as much as youth pick and choose intimates from their larger network, the article also argues that their collective identity as related-kin members remains.

Developing genomic selection for dry matter yield in white clover

Genomic selection (GS) integrates DNA marker and trait data to develop a model that enables prediction of trait performance (genomic-estimated breeding values; GEBVs) based on genotype data alone. GS has been shown to improve the efficiency and effectiveness of breeding programmes, especially for complex traits such dry matter yield (DMY). DMY data were generated from a training population of 200 white clover half-sibling (HS) families assessed in multi-location field trials for two years. We generated a GS prediction model after integrating genotyping-by-sequencing marker data from parents of the HS families with the HS DMY data. We then compared two selection strategies: a conventional method where individuals were chosen randomly from the phenotypically top-ranked HS families (HSP); and another where GEBVs were used to select the best individual from the top-ranked HS families (APWFGS). The mean predicted DMY GEBVs of the selected plants, as well as the predicted response to selection, were compared with those of the base population. This study showed that, compared with conventional selection (HSP), incorporating genomic selection (APWGSHS) is predicted to double the increase in DMY and response to selection relative to the base population. Synthetic populations based on these selections have been generated and will be tested in a field trial to determine empirically the impact of genomic selection for a complex trait.

Friend, foe, or forget ‘em?: The quality of LGBTQ adult sibling relationships

AbstractObjectiveThe present study aims to understand how LGBTQ adults characterize the quality of their adult sibling ties, and how the type of sibling relationship (e.g., full, step, half, chosen) informs this characterization.BackgroundAn intragenerational conflict‐solidarity‐ambivalence frame is developed to theorize and empirically examine sibling relationships.MethodsDrawing on an intragenerational conflict‐solidarity‐ambivalence frame, we analyze qualitative in‐depth interview data from 67 LGBTQ adults who identify as having a sibling.ResultsThe quality of sibling ties was characterized in three primary ways: solidary, wherein an adult sibling perceived their sibling bond(s) as high quality due to exchanges of social/emotional/financial/instrumental support and connection, including LGBTQ support; conflictual, wherein the adult sibling tie is painful because a sibling is problematic, is unsupportive of an LGBTQ identity, or because a sibling creates conflict in a relationship with a parent; and tangential, wherein the sibling relationship was never bonded, is distanced, or siblings have their “own” families and are thus deemed inconsequential. Only full siblings were typified as conflictual, while all sibling types were solidary. Full, step, and half siblings only are characterized as tangential. Differences in sibling quality across gender and sexuality are discussed.ImplicationsThis study contributes to the growing body of research on the quality of family ties in adulthood, providing further insight into how a socially marginalized group is supported, harmed, or perhaps unfazed by their sibling relationships.

Variability of some traits of walnuts (Juglans regia L.) in the test of half sib, originating in the Djerdap forest

As part of efforts for protection and restoration of variability of Juglans regia in Djerdap gorge, Serbia, where it grows as autochthonous relict species, the variability of ten measured and nine derived leaf morphometric parameters of half-sib progenies Persian walnut originating from Djerdap gorge was studied in this work. According to the contribution to total expected variance, parameters that were most effected by differences between half-sib progenies are leaf width (LW), side leaflet length (lL) and top leaflet length (20-30%). Using loadings with the first four rotated principal components, describing 90.1% of total variance, all parameters were grouped in four groups, where parameters LW, lL and lt were in the first group, suggesting multicollinearity between them. These parameters had also relatively high loadings with the first canonical variable from canonical discriminant analysis. Only one of them (lt) was selected by forward stepwise discriminant analysis, where model with four selected leaf parameters achieved 26.5% of correct allocation, while model with all studied parameters achieved 62.4% of correct allocation. Half-sib progenies agglomerated in three clusters, where two small clusters originate from trees that were close to sheltered valleys of small tributaries to river Danube, opposite to mother trees of the first cluster progenies, that were exposed to dominant winds.

Application of ITO Method in Determination of Special Half-Sibling Relationship.

To identify whether the relationship between Zhang A, Zhang B, Zhang C and Zhang X is the half-sibling relationship whose mother is sister (hereinafter referred to as the special half-sibling relationship) or the common first cousin relationship and discuss the application of ITO method in discriminating the special kinship. DNA was extracted from blood stain of four identified individuals, PowerPlex® 21 System and AGCU 21+1 STR kit were used to detect autosomal STR genetic markers. Investigator® Argus X-12 QS kit was used to detect the X chromosome STR genetic markers, the special half-sibling index (SHSI) and first cousin index (FCI) and their likelihood ratio (LR) were calculated by ITO method. The LR results of SHSI to FCI, which were calculated based on autosomal STR genotyping and the analysis of X-STR genotyping results suggested that the relationship between Zhang A, Zhang B, Zhang C and Zhang X was inclined to be a special half-sibling relationship. For the identification of special kinship, it is necessary to comprehensively apply various genetic markers according to the case. After the conclusion that shared alleles cannot be excluded from the analysis, ITO method can be further used to establish discriminant assumptions according to the specific case to obtain objective and reliable identification opinions.

Inbreeding status and implications for Amur tigers

AbstractInbreeding more likely occurs in small, isolated and endangered populations, and may influence the sustainable survival of a population. As the Amur tiger Panthera tigris altaica population in China experienced a severe decline in the 1990s, the recovering population may be prone to inbreeding and its potential impacts on population health. However, the inbreeding status has not been evaluated and relationships with health remain poorly understood in wild animals. Based on the genetic samples collected from the main Amur tiger habitats in China, this study analyzed the population inbreeding level, major histocompatibility complex polymorphism, parasitic infections and gut microbial structures and functions, and then explored the influence of inbreeding on these traits. Our results indicated that more than 50% of individual relationships were in cousin or half sibs, and 22.73% of individuals had moderate or high inbreeding coefficients. There was a significant positive correlation between the inbreeding level of an individual and the Toxocara cati parasitic load. Gut microbiota community structure and function were also impacted by inbreeding intensity. In conclusion, results indicate that the Amur tiger population in China has reached a moderate level of inbreeding and that there are direct interactions between inbreeding intensity and parasitic load and gut microbiota. This study thus provides an early warning on the Amur tiger population health and should prompt the construction of national and international ecological corridors and/or the re‐introduction of new individuals to relieve the evident inbreeding pressure.

Pairwise kinship analysis of 17 pedigrees using massively parallel sequencing

With the tremendous development of massively parallel sequencing (MPS) in the last decade, it has been widely applied in basic science, clinical diagnostics, microbial genomics, as well as forensic genetics. MPS has lots of advantages that may facilitate the kinship analysis. In this study, 243 Chinese Han individuals from 17 families were involved and sequenced using the ForenSeq™ DNA Signature Prep Kit (Verogen, Inc., San Diego, USA), which provided the sequence information of 27 autosomal STRs (A-STRs), 7 X chromosomal STRs (X-STRs), 24 Y chromosomal STRs (Y-STRs) and 94 identity-informative SNPs (iSNPs). A total of 275 pairs of parent-child, 123 pairs of full siblings, 1 pair of twins, 1 pair of half siblings, 158 pairs of grandparent-grandchild, 222 pairs of uncle/aunt-nephew/niece and 121 pairs of first cousins, as well as 701 pairs of unrelated individuals were identified. Using both likelihood ratio (LR) and identical by state (IBS) methods, the kinship analysis was conducted among these relative and non-relative pairs based on the A-STRs and SNPs. As a result, the ForenSeq Signature Kit could solve the analysis of parent-child (t1 = −4, t2 = 4), full siblings (t1 = −2, t2 = 2) and most second-degree kinships (t1 = −1, t2 = 1) using the LR method. When the IBS method was applied, 123 full sibling pairs had a higher average IBS value than other kinship groups in this study. And the IBS method could play a role in the testing of parent-child and full siblings.

Prediction ability of genome-wide markers in Pinus taeda L. within and between population is affected by relatedness to the training population and trait genetic architecture.

Genomic prediction has the potential to significantly increase the rate of genetic gain in tree breeding programs. In this study, a clonally replicated population (n = 2063) was used to train a genomic prediction model. The model was validated both within the training population and in a separate population (n = 451). The prediction abilities from random (20% vs 80%) cross validation within the training population were 0.56 and 0.78 for height and stem form, respectively. Removal of all full-sib relatives within the training population resulted in ∼50% reduction in their genomic prediction ability for both traits. The average prediction ability for all 451 individual trees was 0.29 for height and 0.57 for stem form. The degree of genetic linkage (full-sib family, half sib family, unrelated) between the training and validation sets had a strong impact on prediction ability for stem form but not for height. A dominant dwarfing allele, the first to be reported in a conifer species, was discovered via genome-wide association studies on linkage Group 5 that conferred a 0.33-m mean height reduction. However, the QTL was family specific. The rapid decay of linkage disequilibrium, large genome size, and inconsistencies in marker-QTL linkage phase suggest that large, diverse training populations are needed for genomic selection in Pinus taeda L.

Shared genetic and environmental etiology between substance use disorders and suicidal behavior.

Previous studies have demonstrated substantial associations between substance use disorders (SUD) and suicidal behavior. The current study empirically assesses the extent to which shared genetic and/or environmental factors contribute to associations between alcohol use disorders (AUD) or drug use disorders (DUD) and suicidal behavior, including attempts and death. The authors used Swedish national registry data, including medical, pharmacy, criminal, and death registrations, for a large cohort of twins, full siblings, and half siblings (N = 1 314 990) born 1960-1980 and followed through 2017. They conducted twin-sibling modeling of suicide attempt (SA) or suicide death (SD) with AUD and DUD to estimate genetic and environmental correlations between outcomes. Analyses were stratified by sex. Genetic correlations between SA and SUD ranged from rA = 0.60-0.88; corresponding shared environmental correlations were rC = 0.42-0.89 but accounted for little overall variance; and unique environmental correlations were rE = 0.42-0.57. When replacing attempt with SD, genetic and shared environmental correlations with AUD and DUD were comparable (rA = 0.48-0.72, rC = 0.92-1.00), but were attenuated for unique environmental factors (rE = -0.01 to 0.31). These findings indicate that shared genetic and unique environmental factors contribute to comorbidity of suicidal behavior and SUD, in conjunction with previously reported causal associations. Thus, each outcome should be considered an indicator of risk for the others. Opportunities for joint prevention and intervention, while limited by the polygenic nature of these outcomes, may be feasible considering moderate environmental correlations between SA and SUD.

Kin detection cues and sibling relationship quality in adulthood: The role of childhood co-residence duration and maternal perinatal association

Cues facilitating kin detection among children have been suggested to have a profound impact on adult sibling relationships. Using a large and population-based data of younger and middle-aged Finns, we test how childhood co-residence duration and maternal perinatal association (MPA) correlate with contact frequency, emotional closeness and provision of help between adult siblings. Employing sibling fixed-effect regression models we show that duration of co-residence in childhood and MPA are indeed associated with better relationship quality in all three measures. Provided MPA, sibling relationship quality is high independently of co-residence length, but in the absence of MPA, increased co-residence duration is associated with better relationship quality. Co-residence duration is more strongly associated with provision of help between opposite-gender than same-gender sibling dyads. Full siblings report better relationship quality than half siblings do, although the co-residence duration mediates the effect of genetic relatedness in emotional closeness between full and maternal half siblings and in provision of help between full and paternal half siblings. Moreover, MPA serves as a mediator in the case of emotional closeness between full and maternal half siblings. Our results provide solid support for the importance of childhood kin detection cues for sibling relationship quality in adulthood, and how such cues interact with genetic relatedness and gender.

A Semi-Automated SNP-Based Approach for Contaminant Identification in Biparental Polyploid Populations of Tropical Forage Grasses.

Artificial hybridization plays a fundamental role in plant breeding programs since it generates new genotypic combinations that can result in desirable phenotypes. Depending on the species and mode of reproduction, controlled crosses may be challenging, and contaminating individuals can be introduced accidentally. In this context, the identification of such contaminants is important to avoid compromising further selection cycles, as well as genetic and genomic studies. The main objective of this work was to propose an automated multivariate methodology for the detection and classification of putative contaminants, including apomictic clones (ACs), self-fertilized individuals, half-siblings (HSs), and full contaminants (FCs), in biparental polyploid progenies of tropical forage grasses. We established a pipeline to identify contaminants in genotyping-by-sequencing (GBS) data encoded as allele dosages of single nucleotide polymorphism (SNP) markers by integrating principal component analysis (PCA), genotypic analysis (GA) measures based on Mendelian segregation, and clustering analysis (CA). The combination of these methods allowed for the correct identification of all contaminants in all simulated progenies and the detection of putative contaminants in three real progenies of tropical forage grasses, providing an easy and promising methodology for the identification of contaminants in biparental progenies of tetraploid and hexaploid species. The proposed pipeline was made available through the polyCID Shiny app and can be easily coupled with traditional genetic approaches, such as linkage map construction, thereby increasing the efficiency of breeding programs.

Estimation of Genetic Parameters for Body Weight and Some Colour Traits in the Seventh-generation Index Selected Nigeria Heavy Local Chicken Ecotype

Background: This study was conducted to estimate the genetic parameters of body weight and some colour traits in seventh generation (G7) index selected Nigerian Heavy Local Chicken Ecotype (NHLCE) progenies at point of lay to 12 weeks. Methods: 5 sires and 12 hens were used to generate the progenies used for the experiment. Traits measured included weekly body weight, egg colour, beak colour and feather colour. Data collected were subjected to one way analysis of variance in a Paternal half sib analysis using Animal model of SAS (2003). Four weeks body weight measurements, egg colour, beak colour and feather colour for 5 sires ranged from 1.29±0.05 1.54±0.07; 2.55±0.02 to 4.00±0.02; 2.45±0.02 to 4.83±0.02 and 1.73±0.02 to 4.58±0.04 respectively. Result: The new Duncan’s multiple range test shows that sire families are similar (p greater than 0.05) in the body weight and beak colour, but significantly differed (p greater than 0.05) in the egg colour and feather colour. The heritability estimates of mature body weight for week 3 was medium, while estimates of heritability for weekly mature body weight for weeks 1, 2 and 4, egg colour, beak colour and feather colour of NHLCE were low heritability. Low h2 of traits suggest that progeny and pedigree selection could be employed for improvement of the egg colour, beak colour and feather colour of NHLCE. The study showed positive genetic correlations between beak colour and egg colour, negative genetic correlations between beak and feather colour. This means that no decision can be taken in isolation as the selection of one trait will have consequences on other traits.

Identification of markers for functional traits in Murrah buffaloes

Twelve half sib families were created and two functional traits, viz. age at first heat and age at first calving were recorded for 4,851 and 946 daughters belonging to 12 sires. Partial genome scan was carried out using Interval Mapping with different algorithms. The QTLs obtained for each half sib family were further subjected to meta analysis to identify chromosomal regions associated with age at first heat and age at first calving on 8 chromosomes of buffalo. We identified 4 metaQTL regions on chromosomes BBU1q, BBU6, BBU7, BBU8 and BBU10; 3 metaQTL regions on BBU2q; 2 metaQTL regions on BBU9 and one on BBU15 of buffalo. Comparative genomics was used for finding out genes underlying the meta-QTL regions. 1019 genes were found to be underlying the metaQTL regions in buffaloes assuming buffalo-cattle-human synteny. Several of these genes are supposedly important candidate genes for further analysis as several of them revealed functions related to fertility. The QTL markers identified in the present analysis can be used in the breeding programs of buffalo to select the bulls which affect the functional traits and thus reduce the cost of production.

Characterization of stem volume and form tradeoffs in a northern red oak (Quercus rubra) breeding population in early stages of selection

Quercus rubra half sib progenies (N = 93) expressed high levels of variance for both growth and stem form traits in three locations in Indiana, USA at age 11 or 12. Height, diameter, and volume were measured and sweep, branch angle, forking, and branch retention were rated using a (+ / −) system. Families selected for volume showed no unfavorable increases in sweep or branch angle and only a slight increase in branch retention. Northern red oak (Quercus rubra L.) is the most planted hardwood in the central USA. Red oak seeds from sources with improved growth and form are unavailable in the Central Hardwood Region, in part because the absence of agreed methods for stem form evaluation diminishes the effectiveness of selection. To identify red oak families improved for growth and to determine if a simple + / − rating system could identify red oak families with improved form. We evaluated 93 open-pollinated families of 11 or 12-year-old red oak growing in three sites in central Indiana (USA) for height, diameter, volume, and four traits rated as + / − : sweep, branch angle, forking, and branch retention. Family × location effects were significant for all quantitative traits but not for any binary traits; differences among families were significant for all traits at all sites. Heritabilities for most traits were high. Selection of the top 20 families for volume at each site resulted in no change in population means for sweep or branch angle and only a small increase in the retention of large limbs. A + / − rating system to evaluate hardwood form can help breeders deliver improved red oak to landowners when more complex systems are impractical.

On the Genetic and Environmental Relationship Between Suicide Attempt and Death by Suicide.

The authors examined the extent to which the genetic and environmental etiology of suicide attempt and suicide death is shared or unique. The authors used Swedish national registry data for a large cohort of twins, full siblings, and half siblings (N=1,314,990) born between 1960 and 1990 and followed through 2015. They conducted twin-family modeling of suicide attempt and suicide death to estimate heritability for each outcome, along with genetic and environmental correlations between them. They further assessed the relationship between suicide attempt by young people compared with adults. In bivariate models, suicide attempt and death were moderately heritable among both women (attempt: additive genetic variance component [A]=0.52, 95% CI=0.44, 0.56; death: A=0.45, 95% CI=0.39, 0.59) and men (attempt: A=0.41, 95% CI=0.38, 0.49; death: A=0.44, 95% CI=0.43, 0.44). The outcomes were substantially, but incompletely, genetically correlated (women: rA=0.67, 95% CI=0.55, 0.67; men: rA=0.74, 95% CI=0.63, 0.87). Environmental correlations were weaker (women: rE=0.36, 95% CI=0.29, 0.45; men: rE=0.21, 95% CI=0.19, 0.27). Heritability of suicide attempt was stronger among people ages 10-24 (A=0.55-0.62) than among those age 25 and older (A=0.36-0.38), and the genetic correlation between attempt during youth and during adulthood was stronger for women (rA=0.79, 95% CI=0.72, 0.79) than for men (rA=0.39, 95% CI=0.26, 0.47). The genetic and environmental etiologies of suicide attempt and death are partially overlapping, exhibit modest sex differences, and shift across the life course. These differences must be considered when developing prevention efforts and risk prediction algorithms. Where feasible, suicide attempt and death should be considered separately rather than collapsed, including in the context of gene identification efforts.

Strategies for pairwise searches in forensic kinship analysis

Testing kinship between pairs of individuals is central to a wide range of applications. We focus on cases where many tests are done jointly. Typical examples include cases where DNA profiles are available from a burial site, a plane crash or a database of convicted offenders. The task is to determine the relationships between DNA profiles or individuals. Our approach generalises previous methods and implementations in several respects. We model general, possibly inbred, pairwise relationships which is important for non-human applications and in archaeological studies of ancient inbred populations. Furthermore, we do not restrict attention to autosomal markers. Some cases, such as distinguishing between maternal and paternal half siblings, can be solved using X-chromosomal markers. When many tests are done, the risk of errors increases. We address this problem by building on the theory of multiple testing and show how optimal thresholds for tests can be determined. We point out that the likelihood ratios in a blind search may be dependent so multiple testing methods and interpretation need to account for this. In addition, we show how a Bayesian approach can be helpful. Our examples, using simulated and real data, demonstrate the practical importance of the methods and implementation is based on freely available software.

Genetic improvement of palmarosa (Cymbopogon martini var. motia) for herbage yield and essential oil quality through polycross system of breeding

Palmarosa is one of the commercially important essential oil yielding crops of India. Improving the herbage and essential oil yield through appropriate breeding methods is the major objective of this crop. Being a cross pollinated crop, its improvement can be made through mass selection. Fifteen best palmarosa clones are identified from two years of individual plant screening of seven germplasm material for different growth, yield and quality parameters formed the base material for this study. The slips of fifteen selected clones were planted in the polycross nursery at ICAR-DMAPR, Anand, Gujarat. The composite hybrid seeds of palmarosa were collected separately from each clone from the polycross nursery. In the present study, the performance of composite hybrids along with check was evaluated to identify best performing polycross hybrids for herbage and essential oil yield. Two hybrids DCMH 8 and DCMH 10 had more than 22 per cent higher dry herbage yield than the commercial variety Trishna. The polycross hybrid progeny proved to be significantly superior with respect to essential oil content and percentage of essential oil recovery. Among the hybrids DCMH 8 had the highest oil yield (16.08 g/plant), which was 37.79 per cent higher than check variety. Based on the performance of the polycross composite hybrids, top performing five hybrids viz., DCMH 1, DCMH 6, DCMH 8, DCMH 10, and DCMH 14 were selected and advanced to multi-location trials across different centers to identify the best one for release as a commercial composite variety. Key wordsPolycross breeding, half sib, palmarosa, composite hybrids, essential oil yield.