A male-expressed rice embryogenic trigger redirected for asexual propagation through seeds.

The molecular pathways that trigger the initiation of embryogenesis after fertilization in flowering plants, and prevent its occurrence without fertilization, are not well understood1. Here we show in rice (Oryza sativa) that BABY BOOM1 (BBM1), a member of the AP2 family2 of transcription factors that is expressed in sperm cells, has a key role in this process. Ectopic expression of BBM1 in the egg cell is sufficient for parthenogenesis, which indicates that a single wild-type gene can bypass the fertilization checkpoint in the female gamete. Zygotic expression of BBM1 is initially specific to the male allele but is subsequently biparental, and this is consistent with its observed auto-activation. Triple knockout of the genes BBM1, BBM2 and BBM3 causes embryo arrest and abortion, which are fully rescued by male-transmitted BBM1. These findings suggest that the requirement for fertilization in embryogenesis is mediated by male-genome transmission of pluripotency factors. When genome editing to substitute mitosis for meiosis (MiMe)3,4 is combined with the expression of BBM1 in the egg cell, clonal progeny can be obtained that retain genome-wide parental heterozygosity. The synthetic asexual-propagation trait is heritable through multiple generations of clones. Hybrid crops provide increased yields that cannot be maintained by their progeny owing to genetic segregation. This work establishes the feasibility of asexual reproduction in crops, and could enable the maintenance of hybrids clonally through seed propagation5,6.

Parents' perceptions of personal utility of exome sequencing results.

PURPOSE: Clinical genome or exome sequencing (GS/ES) provides a diagnosis for many individuals with suspected genetic disorders, but also yields negative or uncertain results for the majority. This study examines how parents of a child with an undiagnosed condition attribute personal utility to all types of ES results. METHODS: Return of 31 exome sequencing results was observed during clinic sessions, followed by semistructured interviews with parents one month later. Observations and interviews were recorded and transcribed. Data display matrices were used for content analysis and systematic comparisons of parents' perceptions of utility. RESULTS: ES results could not provide all the answers to parents' questions, especially in cases of clinically uninformative results, but parents nonetheless attributed utility to the knowledge gained. Parents across all results categories used the genomic information to rule out possible causes, end or postpone the diagnostic odyssey, and shift focus to treatment and management of symptoms. CONCLUSION: This study suggests that parents value even uninformative ES results while expressing hope for future discoveries. As pediatric genetics moves toward GS/ES as a first-tier test, how parents perceive the personal utility of negative or uncertain results is an important topic for genetic counseling and further research.

Age and perceived risks and benefits of preventive genomic screening.

PURPOSE: As genome sequencing moves from research to clinical practice, sequencing technologies focused on "medically actionable" targets are being promoted for preventive screening despite the dearth of systematic evidence of risks and benefits and of criteria for selection of screening subjects. This study investigates researchers' and research participants' perceptions of these issues within the context of a preventive genomic screening study, GeneScreen. METHODS: We recorded researcher deliberations regarding age eligibility criteria and the risks and benefits of screening, and conducted interviews with 50 GeneScreen participants about their motivations for joining and their perceptions of risks and benefits. RESULTS: Researchers made assumptions about who would want and benefit from screening based on age. After discussion, researchers opted not to have an upper age limit for enrollment. Participants of all ages perceived similar benefits, including prevention, treatment, and cascade testing, and similar risks, such as insurance discrimination and worry. CONCLUSION: While clinical benefits of preventive genomic screening for older adults are debatable, our respondents perceived a range of benefits of screening in both clinical and research settings. Researchers and clinicians should carefully consider decisions about whether to exclude older adults and whether to provide information about benefits and risks across age groups.

"Possibly positive or certainly uncertain?": participants' responses to uncertain diagnostic results from exome sequencing.

PurposeClinical genome sequencing produces uncertain diagnostic results, raising concerns about how to communicate the method's inherent complexities in ways that reduce potential misunderstandings and harm. This study investigates clinicians' communications and patient/participant responses to uncertain diagnostic results arising from a clinical exome sequencing research study, contributing empirical data to the debate surrounding disclosure of uncertain genomic information.MethodsWe investigated the communication and impact of uncertain diagnostic results using ethnographic observations of result disclosures with 21 adults and 11 parents of child patients, followed by two semistructured interviews with these same participants.ResultsParticipants understood their uncertain results in ways that were congruent with clinical geneticists' communications. They followed recommendations for further consultation, although family testing to resolve uncertainty was not always done. Participants were prepared for learning an uncertain result and grasped the key concept that it should not be used to guide health-care or other decisions. They did not express regret for having learned the uncertain result; most regarded it as potentially valuable in the future.ConclusionThis study suggests that uncertain diagnostic results from genome sequencing can be relayed to patients in ways they can understand and consistent with providers' interpretations, without causing undue harm.

Prenatal exome sequencing in anomalous fetuses: new opportunities and challenges.

PurposeWe investigated the diagnostic and clinical performance of exome sequencing in fetuses with sonographic abnormalities with normal karyotype and microarray and, in some cases, normal gene-specific sequencing.MethodsExome sequencing was performed on DNA from 15 anomalous fetuses and from the peripheral blood of their parents. Parents provided consent to be informed of diagnostic results in the fetus, medically actionable findings in the parents, and their identification as carrier couples for significant autosomal recessive conditions. We assessed the perceptions and understanding of exome sequencing using mixed methods in 15 mother-father dyads.ResultsIn seven (47%) of 15 fetuses, exome sequencing provided a diagnosis or possible diagnosis with identification of variants in the following genes: COL1A1, MUSK, KCTD1, RTTN, TMEM67, PIEZO1 and DYNC2H1. One additional case revealed a de novo nonsense mutation in a novel candidate gene (MAP4K4). The perceived likelihood that exome sequencing would explain the results (5.2 on a 10-point scale) was higher than the approximately 30% diagnostic yield discussed in pretest counseling.ConclusionExome sequencing had diagnostic utility in a highly select population of fetuses where a genetic diagnosis was highly suspected. Challenges related to genetics literacy and variant interpretation must be addressed by highly tailored pre- and posttest genetic counseling.

Conservation of the role of INNER NO OUTER in development of unitegmic ovules of the Solanaceae despite a divergence in protein function.

BACKGROUND: The INNER NO OUTER (INO) gene is expressed in the outermost cell layer of the outer integument of bitegmic ovules and is essential for this organ's growth. The role and cross-species functional conservation of INO orthologs were examined in members of the Solanaceae, which have unitegmic ovules. Unitegmy has evolved several times in disparate angiosperm lineages. INO expression has been observed in the outermost cell layers of all examined unitegmic ovules, but the functional role of INO in unitegmic ovules has not previously been evaluated. RESULTS: INO orthologs were unambiguously identified in tobacco and tomato by sequence homology. Expression of the tomato INO gene was limited to the outer cell layer of the single integument indicating that this single integument has properties of the outer integument. Expression occurred only after integument initiation, later than observed in ovules of other examined angiosperms. Virus-induced knock-down of expression of the INO ortholog in tobacco inhibited growth of the outer cell layer of the integument leading to a decrease in both integument extension and curvature of the ovule. The altered ovules closely resemble those of the aberrant testa shape (ats) ino mutant combination in Arabidopsis where we see the effect of the ino mutation on a single fused integument produced by the ats mutation. Despite significant sequence identity and similar expression patterns, the tomato INO coding region was not able to complement the Arabidopsis ino mutant. CONCLUSIONS: The similarity of effects of ino mutations on the unitegmic ovules of tobacco and the fused integuments of the Arabidopsis ats mutant show that: 1) INO orthologs play the same role in promoting integument growth in ovules of tobacco and Arabidopsis; and 2) the unitegmic ovules of tobacco (and hence other solanaceous species) are most likely the result of a congenital fusion of two ancestral integuments. Our results further indicate that INO has a conserved role in growth of the outermost cell layer of integuments. The curvature of solanaceous ovules is driven by unequal growth of the outer layers of the single integument that likely correspond to an ancestral outer integument.

"Not Tied Up Neatly with a Bow": Professionals' Challenging Cases in Informed Consent for Genomic Sequencing.

As the use of genomic technology has expanded in research and clinical settings, issues surrounding informed consent for genome and exome sequencing have surfaced. Despite the importance of informed consent, little is known about the specific challenges that professionals encounter when consenting patients or research participants for genomic sequencing. We interviewed 29 genetic counselors and research coordinators with considerable experience obtaining informed consent for genomic sequencing to understand their experiences and perspectives. As part of this interview, 24 interviewees discussed an informed consent case they found particularly memorable or challenging. We analyzed these case examples to determine the primary issue or challenge represented by each case. Challenges fell into two domains: participant understanding, and facilitating decisions about testing or research participation. Challenges related to participant understanding included varying levels of general and genomic literacy, difficulty managing participant expectations, and contextual factors that impeded participant understanding. Challenges related to facilitating decision-making included complicated family dynamics such as disagreement or coercion, situations in which it was unclear whether sequencing research would be a good use of participant time or resources, and situations in which the professional experienced disagreement or discomfort with participant decisions. The issues highlighted in these case examples are instructive in preparing genetics professionals to obtain informed consent for genomic sequencing.

The nuanced negative: Meanings of a negative diagnostic result in clinical exome sequencing.

Genomic sequencing technology is moving rapidly from the research setting into clinical medicine but significant technological and interpretive challenges remain. Exome sequencing (ES) in its recent clinical application provides a genetic diagnosis in about 25 per cent of cases (Berg 2014). While this diagnostic yield is substantial, it also indicates that in a majority of cases, patients are receiving negative results (i.e. no explanatory genetic variant found) from this technology. There are a number of uncertainties regarding the meaning of a negative result in the current context of ES. A negative result may be due to current technological limitations that hinder detection of disease-causing variants or to gaps in the knowledge base that prohibit accurate interpretation of their pathogenicity; or it may indicate that there is not a genetic etiology for the disorder. In this paper we examine the uncertainties and nuances of the negative result from genome sequencing and how both clinicians and patients make meaning of it as revealed in ethnographic observations of the clinic session where results are returned, and in interviews with patients. We find that clinicians and patients construct the meaning of a negative result in ways that are uncertain, contingent, and multivalent; but invested with optimism, promise, and potentiality.

Experiences with obtaining informed consent for genomic sequencing.

Despite the increased utilization of genome and exome sequencing, little is known about the actual content and process of informed consent for sequencing. We addressed this by interviewing 29 genetic counselors and research coordinators experienced in obtaining informed consent for sequencing in research and clinical settings. Interviews focused on the process and content of informed consent; patients/participants' common questions, concerns and misperceptions; and challenges to obtaining informed consent. Content analysis of transcribed interviews revealed that the main challenges to obtaining consent related to the broad scope and uncertainty of results, and patient/participants' unrealistic expectations about the likely number and utility of results. Interviewees modified their approach to sessions according to contextual issues surrounding the indication for testing, type of patient, and timing of testing. With experience, most interviewees structured sessions to place less emphasis on standard elements in the consent form and technological aspects of sequencing. They instead focused on addressing misperceptions and helping patients/participants develop realistic expectations about the types and implications of possible results, including secondary findings. These findings suggest that informed consent sessions should focus on key issues that may be misunderstood by patients/participants. Future research should address the extent to which various stakeholders agree on key elements of informed consent.

Symptoms of depression and their management among low-income African-American and White mothers in the rural South.

OBJECTIVE: This study examines experiences of depressive symptoms among a group of 32 low-income, African-American and White mothers of young children who resided in rural Eastern North Carolina, USA. DESIGN: Women's experiences of depressive symptoms were elicited through a series of longitudinal ethnographic interviews, including an explanatory models interview specifically designed to elicit their beliefs about the causes, symptomatology and help-seeking behavior and management of depressive symptoms. RESULTS: A content analysis of interview data indicated that most women (11 African-Americans and 15 Whites) reported having depressive symptoms currently or in the past. Both African-American and White women perceived the main causes of these symptoms as being relationship problems with a spouse, a partner, or a family member; lack of finances; and parenting stresses. There were no differences in the depressive symptoms African-American and White women reported, but there were differences in how they managed these symptoms and where they sought help. Most of the African-American women sought no formal treatment (i.e., pharmacotherapy and/or psychotherapy), but instead turned to their religious faith to deal with their feelings. White women were more likely to seek formal treatment. CONCLUSION: These findings provide insights into the ways in which women in one nonurban area in the USA explained and experienced depressive symptoms and demonstrate differences in help-seeking behaviors that can be linked to beliefs about depression and perceptions of societal responses to those who have it, as well as to perceptions of and experiences with the health-care system. Results have implications for the implementation of education, intervention, and treatment programs in more culturally sensitive ways.

The Arabidopsis INNER NO OUTER (INO) gene acts exclusively and quantitatively in regulation of ovule outer integument development.

The INNER NO OUTER (INO) gene is essential for formation of the outer integument of ovules in Arabidopsis thaliana. Initially described lesions in INO were missense mutations resulting in aberrant mRNA splicing. To determine the null mutant phenotype, we generated frameshift mutations and found, in confirmation of results on another recently identified frameshift mutation, that such mutants have a phenotype identical to the most severe splicing mutant (ino-1), with effects specific to outer integument development. We show that the altered protein of an ino mRNA splicing mutant with a less severe phenotype (ino-4) does not have INO activity, and the mutant is partial because it produces a small amount of correctly spliced INO mRNA. Screening for suppressors of ino-4 in a fast neutron-mutagenized population identified a translocated duplication of the ino-4 gene, leading to an increase in the amount of this mRNA. The increased expression led to a decrease in the severity of the mutant effects, indicating that the amount of INO activity quantitatively regulates outer integument growth. The results further confirm that the role of INO in Arabidopsis development is specific to the outer integument of ovules where it quantitatively affects the growth of this structure.

Caregiver opinions about fragile X population screening.

PURPOSE: We sought to determine caregiver perceptions about population screening for fragile X and to examine factors potentially associated with support for screening. METHODS: We asked 1,099 caregivers of a child with fragile X syndrome or a fragile X carrier to rate whether free, voluntary screening should be offered preconception, prenatally, neonatally, or when problems occur. Caregivers chose a preferred time for screening, reported whether screening would affect parent-child bonding, indicated preferences for carrier detection, and gave reasons for their choices. RESULTS: Caregivers endorsed all forms of screening, but prenatal screening was less strongly endorsed than preconception or postnatal screening. Most (79%) preferred preconception carrier testing, allowing more options when making reproductive decisions. Most thought that screening should also disclose carrier status and believed a positive screen would not negatively affect parent-child bonding. Maternal education, caregiver depression, family impact, and severity of disability were not associated with screening opinions, but parents who only had carrier children were less likely to endorse prenatal screening. CONCLUSION: Caregivers of children with fragile X widely endorse screening. However, because different parents will make different choices, screening may need to be offered at multiple times with careful consideration of consent and informed decision-making.

Enacting genetic responsibility: experiences of mothers who carry the fragile X gene.

A woman who carries the gene for fragile X syndrome (FXS) has a 50 per cent chance per pregnancy of passing the gene to her sons and daughters. In this paper we analyse interview data from mothers who are carriers of the FX gene, and who have at least one child with FXS, to examine how their understandings and enactments of reproductive options, obligations, and responsibilities support an expanded notion of genetic responsibility. Accounts of 108 women from across the United States show that the majority of mothers chose not to have another biological child once they learned their carrier status. They discussed genetic responsibility and reproductive agency in terms of an obligation not to risk having another child who carried the gene, although their accounts reflected the tensions that arose from managing oneself as a genetically at-risk actor. Another 22 mothers either purposely became pregnant or continued an unplanned pregnancy after finding out their carrier status. These mothers' accounts reflect an expanded version of genetic responsibility that incorporates ideas and values beyond managing risk in what it means to act responsibly in light of genetic knowledge.

Functional conservation of the grapevine candidate gene INNER NO OUTER for ovule development and seed formation.

Seedlessness represents a highly appreciated trait in table grapes. Based on an interesting case of seedless fruit production described in the crop species Annona squamosa, we focused on the Vitis vinifera INNER NO OUTER (INO) gene as a candidate. This gene encodes a transcription factor belonging to the YABBY family involved in the determination of abaxial identity in several organs. In Arabidopsis thaliana, this gene was shown to be essential for the formation and asymmetric growth of the ovule outer integument and its mutation leads to a phenotypic defect of ovules and failure in seed formation. In this study, we identified in silico the V. vinifera orthologue and investigated its phylogenetic relationship to INO genes from other species and its expression in different organs in seeded and seedless varieties. Applying cross-species complementation, we have tested its functionality in the Arabidopsis ino-1 mutant. We show that the V. vinifera INO successfully rescues the ovule outer integument growth and seeds set and also partially complements the outer integument asymmetric growth in the Arabidopsis mutant, differently from orthologues from other species. These data demonstrate that VviINO retains similar activity and protein targets in grapevine as in Arabidopsis. Potential implications for grapevine breeding are discussed.

Roles of polarity determinants in ovule development.

Ovules are the female reproductive structures that develop into seeds. Angiosperm ovules include one, or more commonly two, integuments that cover the nucellus and female gametophyte. Mutations in the Arabidopsis KANADI (KAN) and YABBY polarity genes result in amorphous or arrested integument growth, suggesting that polarity determinants play key roles in ovule development. We show that the class III homeodomain leucine zipper (HD-ZIPIII) genes CORONA (CNA), PHABULOSA (PHB) and PHAVOLUTA (PHV) are expressed adaxially in the inner integument during ovule development, independent of ABERRANT TESTA SHAPE (ATS, also known as KANADI4) activity. Loss of function of these genes leads to aberrant integument growth. Additionally, over-expression of PHB or PHV in ovules is not sufficient to repress ATS expression, and can produce phenotypes similar to those of the HD-ZIPIII loss-of-function lines. The absence of evidence of mutual negative regulation by KAN and HD-ZIPIII transcription factors is in contrast to known mechanisms in leaves. Loss of HD-ZIPIII activity can partially compensate for loss of ATS activity in the ats cna phb phv quadruple mutant, showing that CNA/PHB/PHV act in concert with ATS to control integument morphogenesis. In a parallel pathway, ATS acts with REVOLUTA (REV) to restrict expression of INNER NO OUTER (INO) and outer integument growth. Based on these expression and genetic studies, we propose a model in which a balance between the relative levels of adaxial/abaxial activities, rather than maintenance of boundaries of expression domains, is necessary to support laminar growth of the two integuments.

Expression-based discovery of candidate ovule development regulators through transcriptional profiling of ovule mutants.

BACKGROUND: Arabidopsis ovules comprise four morphologically distinct parts: the nucellus, which contains the embryo sac, two integuments that become the seed coat, and the funiculus that anchors the ovule within the carpel. Analysis of developmental mutants has shown that ovule morphogenesis relies on tightly regulated genetic interactions that can serve as a model for developmental regulation. Redundancy, pleiotropic effects and subtle phenotypes may preclude identification of mutants affecting some processes in screens for phenotypic changes. Expression-based gene discovery can be used access such obscured genes. RESULTS: Affymetrix microarrays were used for expression-based gene discovery to identify sets of genes expressed in either or both integuments. The genes were identified by comparison of pistil mRNA from wild type with mRNA from two mutants; inner no outer (ino, which lacks the outer integument), and aintegumenta (ant, which lacks both integuments). Pools of pistils representing early and late stages of ovule development were evaluated and data from the three genotypes were used to designate genes that were predominantly expressed in the integuments using pair-wise and cluster analyses. Approximately two hundred genes were found to have a high probability of preferential expression in these structures, and the predictive nature of the expression classes was confirmed with reverse transcriptase polymerase chain reaction and in situ hybridization. CONCLUSION: The results showed that it was possible to use a mutant, ant, with broad effects on plant phenotype to identify genes expressed specifically in ovules, when coupled with predictions from known gene expression patterns, or in combination with a more specific mutant, ino. Robust microarray averaging (RMA) analysis of array data provided the most reliable comparisons, especially for weakly expressed genes. The studies yielded an over-abundance of transcriptional regulators in the identified genes, and these form a set of candidate genes for evaluation of roles in ovule development using reverse genetics.

Supporting family adaptation to presymptomatic and "untreatable" conditions in an era of expanded newborn screening.

OBJECTIVE: As technology advances, newborn screening will be possible for conditions not screened today. With an expansion of screening, strategies will be needed to support family adaptation to unexpected and possibly uncertain genetic information provided shortly after birth. METHOD: Although candidate conditions for expanded newborn screening will typically be associated with increased morbidity or mortality, for most there is no proven medical treatment that must be implemented quickly. Many will have clinical features that gradually emerge and for which the severity of impact is not predictable. Parents will seek guidance on information, support, and treatment possibilities. This article summarizes issues evoked by expanded newborn screening and suggests strategies for supporting families of identified children. RESULTS: We propose four components necessary to support family adaptation to pre-symptomatic and "untreatable" conditions in an era of expanded newborn screening: (1) accurate and understandable information; (2) formal and informal support; (3) active surveillance; and (4) general and targeted interventions. We argue that no condition is "untreatable" and that a well-designed program of prevention and support has the potential to maximize benefit and minimize harm. CONCLUSIONS: Pediatric psychologists can play important roles in an era of expanded newborn screening by helping families understand genetic information, make informed decisions about genetic testing, and cope with the potential psychosocial consequences of genetic information.

How parents search, interpret, and evaluate genetic information obtained from the internet.

This study describes how parents of a child referred for genetic services searched the Internet for information, summarizes how they interpreted and evaluated the information they obtained, and identifies barriers that they encountered. Audio-taped interviews were conducted with 100 ethnically diverse families referred to a pediatric genetics clinic. After transcription, coded text was entered into a software program (QSR N6) for searching and data retrieval. Matrices were created to systematically categorize and compare families' Internet use. Eighty-three percent of families obtained Internet information about the diagnosis, the clinic visit, and/or treatment and services. Those not conducting searches lacked access, Internet experience, or a diagnostic term and had lower incomes and less education, regardless of ethnicity. Families sought information in preparation for the clinic visit but barriers to obtaining and interpreting relevant information were common. Parents' Internet searching experiences illustrate common barriers to obtaining and understanding genetic information. Identifying them can help genetic counselors facilitate parents' searches for relevant information.

Development and evolution of the unique ovules of flowering plants.

Ovules are the precursors to seeds and as such are critical to plant propagation and food production. Mutant studies have led to the identification of numerous genes regulating ovule development. Genes encoding transcription factors have been shown to direct ovule spacing, ovule identity and integument formation. Particular co-regulators have now been associated with activities of some of these transcription factors, and other protein families including cell surface receptors have been shown to regulate ovule development. Hormone levels and transport, especially of auxin, have also been shown to play critical roles in ovule emergence and morphogenesis and to interact with the transcriptional regulators. Ovule diversification has been studied using orthologs of regulatory genes in divergent angiosperm groups. Combining modern genetic evidence with expanding knowledge of the fossil record illuminates the possible origin of the unique bitegmic ovules of angiosperms.