In budding yeast, at least 10 proteins are required for formation of the double-strand breaks (DSBs) that initiate meiotic recombination. Spo11 is the enzyme responsible for cleaving DNA and is found in a complex that also contains Ski8, Rec102, and Rec104. The Mre11/Rad50/Xrs2 complex is required for both DSB formation and DSB processing. In this article we investigate the functions of the remaining three proteins-Mer2, Mei4, and Rec114-with particular emphasis on Mer2. The Mer2 protein is present in vegetative cells, but it increases in abundance and becomes phosphorylated specifically during meiotic prophase. Mer2 localizes to distinct foci on meiotic chromosomes, with foci maximally abundant prior to the formation of synaptonemal complex. If DSB formation is blocked (e.g., by a spo11 mutation), dephosphorylation of Mer2 and its dissociation from chromosomes are delayed. We have also found that the Mei4 and Rec114 proteins localize to foci on chromosomes and these foci partially colocalize with each other and with Mer2. Furthermore, the three proteins co-immunoprecipitate. Mer2 does not show significant colocalization with Mre11 or Rec102 and Mer2 does not co-immunoprecipitate with Rec102. We propose that Mer2, Mei4, and Rec114 form a distinct complex required for DSB formation.

Providers and patients encounter challenges related to the management of Variants of Unknown Significance (VUS). A VUS introduces new counseling dilemmas for the understanding and psychosocial impact of uncertain genetic test results. This descriptive study uses Mishel's theory of uncertainty in illness to explore the experience of individuals who have received a VUS as part of the genetic testing process. Semi-structured interviews were conducted with 27 adult individuals who received a VUS for Lynch syndrome mismatch repair genes between 2002 and 2013. The interviews were transcribed and analyzed. Most individuals recalled their result and perceived various types of uncertainty associated with their VUS. Half of the participants appraised their variant as a danger and implemented coping strategies to reduce the threat of developing cancer. Mobilizing strategies to reduce their risk included vigilant cancer surveillance, information seeking and notifying relatives. The majority of participants were unaware of the possibility of a VUS before receiving their result and expected reclassification over time. These results provide insight into the ways healthcare providers can support patients who receive VUS for Lynch syndrome. Findings also provide direction for future work that can further explicate the impact of receiving a VUS.

Exome sequencing is being offered for children with undiagnosed conditions to identify a primary (causative) variant. Parental preferences for learning secondary (incidental) variants are largely unexplored. Our objective was to characterize values and beliefs that shape parents’ preferences for learning their children’s sequencing results. We conducted semi-structured interviews with 25 parents of 13 minor probands with a variety of rare genetic conditions. Parents were asked to discuss their preferences to receive four types of results from exome sequencing. Many parents preferred to receive all types of results. Parents had the most positive attitudes toward learning about variants that predispose to disorders treatable or preventable in childhood. They had reservations about learning about predispositions for untreatable adult-onset conditions and carrier status for recessive conditions. Parents described their success in coping with their child’s condition as evidence for an ability to manage any additional negative health information. They felt responsible for learning about secondary variants, desiring a gain in control over their child’s health. Our findings suggest that investigators should incorporate parents’ perceptions of the value in receiving secondary variant information about their children when designing studies employing exome sequencing.

During meiotic prophase, homologous chromosomes engage in a complex series of interactions that ensure their proper segregation at meiosis I. A central player in these interactions is the synaptonemal complex (SC), a proteinaceous structure elaborated along the lengths of paired homologs. In mutants that fail to make SC, crossing over is decreased, and chromosomes frequently fail to recombine; consequently, many meiotic products are inviable because of aneuploidy. Here, we have investigated the role of the small ubiquitin-like protein modifier (SUMO) in SC formation during meiosis in budding yeast. We show that SUMO localizes specifically to synapsed regions of meiotic chromosomes and that this localization depends on Zip1, a major building block of the SC. A non-null allele of the UBC9 gene, which encodes the SUMO-conjugating enzyme, impairs Zip1 polymerization along chromosomes. The Ubc9 protein localizes to meiotic chromosomes, coincident with SUMO staining. In the zip1 mutant, SUMO localizes to discrete foci on chromosomes. These foci coincide with axial associations, where proteins involved in synapsis initiation are located. Our data suggest a model in which SUMO modification of chromosomal proteins promotes polymerization of Zip1 along chromosomes. The ubc9 mutant phenotype provides the first evidence for a cause-and-effect relationship between sumoylation and synapsis.

Gnathostome vertebrates have multiple members of the Dlx family of transcription factors that are expressed during the development of several tissues considered to be vertebrate synapomorphies, including the forebrain, cranial neural crest, placodes, and pharyngeal arches. The Dlx gene family thus presents an ideal system in which to examine the relationship between gene duplication and morphological innovation during vertebrate evolution. Toward this end, we have cloned Dlx genes from the lamprey Petromyzon marinus, an agnathan vertebrate that occupies a critical phylogenetic position between cephalochordates and gnathostomes. We have identified four Dlx genes in P. marinus, whose orthology with gnathostome Dlx genes provides a model for how this gene family evolved in the vertebrate lineage. Differential expression of these lamprey Dlx genes in the forebrain, cranial neural crest, pharyngeal arches, and sensory placodes of lamprey embryos provides insight into the developmental evolution of these structures as well as a model of regulatory evolution after Dlx gene duplication events.

Genetic testing and spending on that testing have grown rapidly since the mapping of the human genome in 2003. However, it is not widely known how many tests there are, how they are used, and how they are paid for. Little evidence from large data sets about their use has emerged. We shed light on the issue of genetic testing by providing an overview of the testing landscape. We examined test availability and spending for the full spectrum of genetic tests, using unique data sources on test availability and commercial payer spending for privately insured populations, focusing particularly on tests measuring multiple genes in the period 2014–17. We found that there were approximately 75,000 genetic tests on the market, with about ten new tests entering the market daily. Prenatal tests accounted for the highest percentage of spending on genetic tests, and spending on hereditary cancer tests accounted for the second-highest. Our results provide insights for those interested in assessing genetic testing markets, test usage, and health policy implications, including current debates over the most appropriate regulatory and payer coverage mechanisms.

PurposeThis study investigated how genome sequencing results affect health behaviors, affect, and communication.MethodsWe report on 29 participants who received a sequence result in the ClinSeq® study, a cohort of well-educated, post-reproductive volunteers. A mixed methods design was used to explore respondents’ use, communication, and perceived utility of results.ResultsMost participants (72%) shared their result with at least one health care provider, and 31% reported changes to their health care. Participants scored high on the Positive Experiences subscale and low on the Distress subscale of a modified version of the Multidimensional Impact of Cancer Risk Assessment (MICRA). The majority (93%) shared their result with at least one family member. Participant’s described deriving personal utility from their results.ConclusionsThis paper is the first to describe research participants’ reactions to actionable sequencing results. Our findings suggest clinical and personal benefit from receiving sequencing results, both of which may contribute to improved health for the recipients. Given the participants’ largely positive or neutral affective responses and disclosure of their results to physicians and relatives, health care providers should redirect concern from the potential for distress and attend to motivating patients to follow their medical recommendations.

Telephone genetic counseling (TC) for hereditary breast/ovarian cancer risk has been associated with positive outcomes in high risk women. However, little is known about how patients perceive TC. As part of a randomized trial of TC versus usual care (UC; in-person genetic counseling), we compared high risk women’s perceptions of: (1) overall satisfaction with genetic counseling; (2) convenience; (3) attentiveness during the session; (4) counselor effectiveness in providing support; and (5) counselor ability to recognize emotional responses during the session. Among the 554 participants (TC, N=272; UC, N=282), delivery mode was not associated with self-reported satisfaction. However, TC participants found counseling significantly more convenient than UC participants (OR = 4.78, 95% CI = 3.32, 6.89) while also perceiving lower levels of support (OR=0.56, 95% CI=0.40–0.80) and emotional recognition (OR = 0.53, 95% CI = 0.37–0.76). In exploratory analyses, we found that non-Hispanic white participants reported higher counselor support in UC than in TC (69.4% vs. 52.8%; OR = 3.06, 95% CI = 1.39–6.74), while minority women perceived less support in UC vs. TC (58.3% vs. 38.7%; OR = 0.80, 95% CI = 0.39–1.65). We discuss potential research and practice implications of these findings which may further improve the effectiveness and utilization of TC.