Gregor Mendel developed the principles of segregation and independent assortment in the mid-1800s based on his detailed analysis of several traits in pea plants. Those principles, now called Mendel\'s laws, in fact, explain the behavior of genes and alleles during meiosis and are now understood to underlie \"Mendelian inheritance\" of a wide range of traits and diseases across organisms. When asked to give examples of inheritance that do NOT follow Mendel\'s laws, in other words, examples of non-Mendelian inheritance, students sometimes list incomplete dominance, codominance, multiple alleles, sex-linked traits, and multigene traits and cite as their sources the Khan Academy, Wikipedia, and other online sites. Against this background, the goals of this Perspective are to (1) explain to students, healthcare workers, and other stakeholders why the examples above, in fact, display Mendelian inheritance, as they obey Mendel\'s laws of segregation and independent assortment, even though they do not produce classic Mendelian phenotypic ratios and (2) urge individuals with an intimate knowledge of genetic principles to monitor the accuracy of learning resources and work with us and those resources to correct information that is misleading.

Endometriosis is a complex disease that affects 10-15% of women of reproductive age. Familial studies show that relatives of affected patients have a higher risk of developing the disease, implicating a genetic role for this disorder. Little is known about the impact of germline genomic copy number variant (CNV) polymorphisms on the heredity of the disease. In this study, we describe a rare CNV identified in two sisters with familial endometriosis, which contain genes that may increase the susceptibility and progression of this disease. We investigated the presence of CNVs from the endometrium and blood of the sisters with endometriosis and normal endometrium of five women as controls without the disease using array-CGH through the Agilent 2x400K platform. We excluded common CNVs that were present in the database of genomic variation. We identified, in both sisters, a rare CNV gain affecting 113kb at band 3q12.2 involving two candidate genes: ADGRG7 and TFG. The CNV gain was validated by qPCR. ADGRG7 is located at 3q12.2 and encodes a G protein-coupled receptor influencing the NF-kappaβ pathway. TFG participates in chromosomal translocations associated with hematologic tumor and soft tissue sarcomas, and is also involved in the NF-kappa B pathway. The CNV gain in this family provides a new candidate genetic marker for future familial endometriosis studies. Additional longitudinal studies of affected families must confirm any associations between this rare CNV gain and genes involved in the NF-kappaβ pathway in predisposition to endometriosis.

Heritable gene silencing has been proposed to rely on DNA methylation, histone modifications, and/or non-coding RNAs in different organisms. Here we demonstrate that multiple RNA-mediated mechanisms with distinct and easily detectable molecular signatures can underlie heritable silencing of the same open-reading frame in the nematode C. elegans. Using two-gene operons, we reveal three cases of gene-selective silencing that provide support for the transmission of heritable epigenetic changes through different mechanisms of RNA silencing independent of changes in chromatin that would affect all genes of an operon equally. Different heritable epigenetic states of a gene were associated with distinct populations of stabilized mRNA fragments with untemplated poly-UG (pUG) tails, which are known intermediates of RNA silencing. These \'pUG signatures\' provide a way to distinguish the multiple mechanisms that can drive heritable RNA silencing of a single gene.

Interacting molecules create regulatory architectures that can persist despite turnover of molecules. Although epigenetic changes occur within the context of such architectures, there is limited understanding of how they can influence the heritability of changes. Here, I develop criteria for the heritability of regulatory architectures and use quantitative simulations of interacting regulators parsed as entities, their sensors, and the sensed properties to analyze how architectures influence heritable epigenetic changes. Information contained in regulatory architectures grows rapidly with the number of interacting molecules and its transmission requires positive feedback loops. While these architectures can recover after many epigenetic perturbations, some resulting changes can become permanently heritable. Architectures that are otherwise unstable can become heritable through periodic interactions with external regulators, which suggests that mortal somatic lineages with cells that reproducibly interact with the immortal germ lineage could make a wider variety of architectures heritable. Differential inhibition of the positive feedback loops that transmit regulatory architectures across generations can explain the gene-specific differences in heritable RNA silencing observed in the nematode Caenorhabditis elegans. More broadly, these results provide a foundation for analyzing the inheritance of epigenetic changes within the context of the regulatory architectures implemented using diverse molecules in different living systems.

In recent years, the prevalence of myopia has gradually increased, and it has become a significant global public health problem in the 21st century, posing a serious challenge to human eye health. Currently, it is confirmed that the development of myopia is attributed to the combined action of genes and environmental factors. Thus, elucidating the risk factors and pathogenesis of myopia is of great significance for the prevention and control of myopia. To elucidate the impact of gene-environment interaction on myopia, we used the Pubmed database to search for literature related to myopia. Search terms are as follows: myopia, genes, environmental factors, gene-environment interaction, and treatment. This paper reviews the effects of gene and environmental interaction on myopia.

BACKGROUND: Neurofibromatosis type I (NF1) is a genetic disorder characterized by the tumor\'s development in nerve tissue. Complications of NF1 can include pigmented lesions, skin neurofibromas, and heart problems such as cardiomyopathy. In this study, we performed whole-exome sequencing (WES) on an Iranian patient with NF1 to identify the genetic cause of the disease.
METHODS: Following clinical assessment, WES was used to identify genetic variants in a family with a son suffering from NF1. No symptomatic manifestations were observed in other family members. In the studied family, in silico and segregation analysis were applied to survey candidate variants.
RESULTS: Clinical manifestations were consistent with arrhythmogenic cardiomyopathy (ACM). WES detected a likely pathogenic heterozygous missense variant, c.3277G > A:p.Val1093Met, in the NF1 gene, confirmed by PCR and Sanger sequencing. The patient\'s parents and brother had a normal sequence at this locus.
CONCLUSIONS: Although there is no cure for NF1, genetic tests, such as WES, can detect at-risk asymptomatic family members. Furthermore, cardiac evaluation could also help these patients before heart disease development.

BACKGROUND: Bipolar disorder (BD) and obsessive-compulsive disorder (OCD) comorbidity is an emerging condition in psychiatry, with relevant nosological, clinical, and therapeutic implications.
METHODS: We updated our previous systematic review on epidemiology and standard diagnostic validators (including phenomenology, course of illness, heredity, biological markers, and treatment response) of BD-OCD. Relevant papers published until (and including) 15 October 2023 were identified by searching the electronic databases MEDLINE, Embase, PsychINFO, and Cochrane Library, according to the PRISMA statement (PROSPERO registration number, CRD42021267685).
RESULTS: We identified 38 new articles, which added to the previous 64 and raised the total to 102. The lifetime comorbidity prevalence ranged from 0.26 to 27.8% for BD and from 0.3 to 53.3% for OCD. The onset of the two disorders appears to be often overlapping, although the appearance of the primary disorder may influence the outcome. Compared to a single diagnosis, BD-OCD exhibited a distinct pattern of OC symptoms typically following an episodic course, occurring in up to 75% of cases (vs. 3%). Notably, these OC symptoms tended to worsen during depressive episodes (78%) and improve during manic or hypomanic episodes (64%). Similarly, a BD course appears to be chronic in individuals with BD-OCD in comparison to patients without. Additionally, individuals with BD-OCD comorbidity experienced more depressive episodes (mean of 8.9 ± 4.2) compared to those without comorbidity (mean of 4.1 ± 2.7).
CONCLUSIONS: We found a greater likelihood of antidepressant-induced manic/hypomanic episodes (60% vs. 4.1%), and mood stabilizers with antipsychotic add-ons emerging as a preferred treatment. In line with our previous work, BD-OCD comorbidity encompasses a condition of greater nosological and clinical complexity than individual disorders.

This essay argues that scrofula was one of several disorders, including gout, rickets, and venereal disease, that were \'rebranded\' as hereditary in response to broader cultural changes that took place during the Restoration and eighteenth century in England. While the purposes of scrofula\'s recategorisation were more political than medical, they resulted in this heretofore relatively obscure childhood ailment assuming a new prominence within both medical and popular discourses of the period. Scrofula became both emblem and proof of the links between sexual promiscuity, financial profligacy, and physiological degeneration, its symbolic status reinforced by the legal and moral language used to model processes of hereditary transmission. By likening the inheritance of scrofula to the inheritance of original sin-or, more commonly, to the inheritance of a \'docked entail\' or damaged estate-eighteenth-century writers and artists not only made this non-inherited ailment into a sign of catastrophic hereditary decline; they also paved the way for scrofula to be identified as a disease of aristocratic vice, even though its association with crowded, unsanitary living conditions likely made it more common among the poor. By the same token, financial models of disease inheritance facilitated a bias toward paternal transmission, with scrofula often portrayed as passing, like a title or an estate, from father to son rather than from mother to daughter.

The selection of honeybee strains resistant to the ectoparasitic mite Varroa destructor is generally considered as one of the most sustainable ways of coping with this major bee parasite. Thus, breeding efforts increasingly focus on resistance parameters in addition to common beekeeping traits like honey yield and gentleness. In every breeding effort, the success strongly depends on the quantifiability and heritability of the traits accounted. To find the most suitable traits among the manifold variants to assess Varroa resistance, it is necessary to evaluate how easily a trait can be measured (i.e., testing effort) in relation to the underlying heritability (i.e., expected transfer to the following generation). Various possible selection traits are described as beneficial for colony survival in the presence of Varroa destructor and therefore are measured in breeding stocks around the globe. Two of them in particular, suppressed mite reproduction (SMR, sensu lato any reproductive failure of mother mites) and recapping of already sealed brood cells have recently gained increasing attention among the breeders because they closely resemble resistance mechanisms of some Varroa-surviving honeybee populations. However, it was still unknown whether the genetic background of the trait is sufficient for targeted selection. We therefore investigated the heritabilities and genetic correlations for SMR and REC, distinguishing between recapping of infested cells (RECinf) and all cells (RECall), on an extensive dataset of Buckfast and Carniolan stock in Germany. With an accessible h² of 0.18 and 0.44 for SMR and an accessible h² of 0.44 and 0.40 for RECinf, both traits turned out to be very promising for further selection in the Buckfast and Carnica breeding population, respectively.

Recently, we described the alteration of six miRNAs in the serum of autistic children, their fathers, mothers, siblings, and in the sperm of autistic mouse models. Studies in model organisms suggest that noncoding RNAs participate in transcriptional modulation pathways. Using mice, approaches to alter the amount of RNA in fertilized eggs enable in vivo intervention at an early stage of development. Noncoding RNAs are very numerous in spermatozoa. Our study addresses a fundamental question: can the transfer of RNA content from sperm to eggs result in changes in phenotypic traits, such as autism? To explore this, we used sperm RNA from a normal father but with autistic children to create mouse models for autism. Here, we induced, in a single step by microinjecting sperm RNA into fertilized mouse eggs, a transcriptional alteration with the transformation in adults of glial cells into cells affected by astrogliosis and microgliosis developing deficiency disorders of the \'autism-like\' type in mice born following these manipulations. Human sperm RNA alters gene expression in mice, and validates the possibility of non-Mendelian inheritance in autism.