Humans are curious to understand the causes of traits that distinguish us from other animals and that distinguish vastly different species from one another. We also have a proclivity for simple stories and sometimes tend toward seeking and accepting simple genetic explanations for large evolutionary shifts, even to a single gene. Here, I reveal how a biased expectation of mechanistic simplicity threads through the long history of evolutionary and developmental genetics.
View Article and Find Full Text PDFUnderstanding the management of asymptomatic bacteriuria (ASB) is important given the prevalence of the condition, associated risks in certain patient populations, and the risks associated with inappropriate antibiotic administration. Generally, screening and treatment is only recommended in pregnant women and in those undergoing urologic procedures that will violate the urothelium. Knowing the appropriate time to screen and treat ASB is critical for managing high-risk patients and preventing the growth of antibiotic resistance.
View Article and Find Full Text PDFTails used as inertial appendages induce body rotations of animals and robots-a phenomenon that is governed largely by the ratio of the body and tail moments of inertia. However, vertebrate tails have more degrees of freedom (e.g.
View Article and Find Full Text PDFVertebrate animals that run or jump across sparsely vegetated habitats, such as horses and jerboas, have reduced the number of distal limb bones, and many have lost most or all distal limb muscle. We previously showed that nascent muscles are present in the jerboa hindfoot at birth and that these myofibers are rapidly and completely lost soon after by a process that shares features with pathological skeletal muscle atrophy. Here, we apply an intra- and interspecies differential RNA-Seq approach, comparing jerboa and mouse muscles, to identify gene expression differences associated with the initiation and progression of jerboa hindfoot muscle loss.
View Article and Find Full Text PDFHind limbs undergo dramatic changes in loading conditions during the transition from quadrupedal to bipedal locomotion. For example, the most early diverging bipedal jerboas (Rodentia: Dipodidae) are some of the smallest mammals in the world, with body masses that range between 2-4 g. The larger jerboa species exhibit developmental and evolutionary fusion of the central three metatarsals into a single cannon bone.
View Article and Find Full Text PDFGenetic elements that are inherited at super-Mendelian frequencies could be used in a 'gene drive' to spread an allele to high prevalence in a population with the goal of eliminating invasive species or disease vectors. We recently demonstrated that the gene conversion mechanism underlying a CRISPR-Cas9-mediated gene drive is feasible in mice. Although substantial technical hurdles remain, overcoming these could lead to strategies that might decrease the spread of rodent-borne Lyme disease or eliminate invasive populations of mice and rats that devastate island ecology.
View Article and Find Full Text PDFHighly efficient gene conversion systems have the potential to facilitate the study of complex genetic traits using laboratory mice and, if implemented as a "gene drive," to limit loss of biodiversity and disease transmission caused by wild rodent populations. We previously showed that such a system of gene conversion from heterozygous to homozygous after a sequence targeted CRISPR/Cas9 double-strand DNA break (DSB) is feasible in the female mouse germline. In the male germline, however, all DSBs were instead repaired by end joining (EJ) mechanisms to form an "insertion/deletion" (indel) mutation.
View Article and Find Full Text PDFDespite the great diversity of vertebrate limb proportion and our deep understanding of the genetic mechanisms that drive skeletal elongation, little is known about how individual bones reach different lengths in any species. Here, we directly compare the transcriptomes of homologous growth cartilages of the mouse (Mus musculus) and bipedal jerboa (Jaculus jaculus), the latter of which has "mouse-like" arms but extremely long metatarsals of the feet. Intersecting gene-expression differences in metatarsals and forearms of the two species revealed that about 10% of orthologous genes are associated with the disproportionately rapid elongation of neonatal jerboa feet.
View Article and Find Full Text PDFNaturalists leading up to the early 20th century were captivated by the diversity of limb form and function and described its development in a variety of species. The advent of discoveries in genetics followed by molecular biology led to focused efforts in few 'model' species, namely mouse and chicken, to understand conserved mechanisms of limb axis specification and development of the musculoskeletal system. 'Non-traditional' species largely fell by the wayside until their recent resurgence into the spotlight with advances in next-generation sequencing technologies (NGS).
View Article and Find Full Text PDFThe development and evolution of multicellular body plans is complex. Many distinct organs and body parts must be reproduced at each generation, and those that are traceable over long time scales are considered homologous. Among the most pressing and least understood phenomena in evolutionary biology is the mode by which new homologs, or "novelties" are introduced to the body plan and whether the developmental changes associated with such evolution deserve special treatment.
View Article and Find Full Text PDFHaematopoietic stem and progenitor cells (HSPCs) have been the focus of developmental and regenerative studies, yet our understanding of the signalling events regulating their specification remains incomplete. We demonstrate that supt16h, a component of the Facilitates chromatin transcription (FACT) complex, is required for HSPC formation. Zebrafish supt16h mutants express reduced levels of Notch-signalling components, genes essential for HSPC development, due to abrogated transcription.
View Article and Find Full Text PDFGrowth plate and articular cartilage constitute a single anatomical entity early in development but later separate into two distinct structures by the secondary ossification center (SOC). The reason for such separation remains unknown. We found that evolutionarily SOC appears in animals conquering the land - amniotes.
View Article and Find Full Text PDFThe management of small, non-obstructing renal stones in adults with recurrent lower urinary tract infections remains unclear. Whereas for larger or obstructing stones the decision to intervene becomes clearer, for stones smaller than 5 to 6 mm the decision to intervene requires consideration of multiple factors. This review describes these factors, including history, imaging, laboratory studies, as well as a comprehensive review of the literature.
View Article and Find Full Text PDFAn Amendment to this paper has been published and can be accessed via a link at the top of the paper.
View Article and Find Full Text PDFDependence on the 26S proteasome is an Achilles' heel for triple-negative breast cancer (TNBC) and multiple myeloma (MM). The therapeutic proteasome inhibitor, bortezomib, successfully targets MM but often leads to drug-resistant disease relapse and fails in breast cancer. Here we show that a 26S proteasome-regulating kinase, DYRK2, is a therapeutic target for both MM and TNBC.
View Article and Find Full Text PDFIn many vertebrate animals that run or leap, the metatarsals and/or metacarpals of the distal limb are fused into a single larger element, likely to resist fracture due to high ground-reaction forces during locomotion. Although metapodial fusion evolved independently in modern birds, ungulates, and jerboas, the developmental basis has only been explored in chickens, which diverged from the mammalian lineage approximately 300 million years ago. Here, we use a bipedal rodent, the lesser Egyptian jerboa (Jaculus jaculus), to understand the cellular processes of metatarsal fusion in a mammal, and we revisit the developing chicken to assess similarities and differences in the localization of osteoblast and osteoclast activities.
View Article and Find Full Text PDFMany species that run or leap across sparsely vegetated habitats, including horses and deer, evolved the severe reduction or complete loss of foot muscles as skeletal elements elongated and digits were lost, and yet the developmental mechanisms remain unknown. Here, we report the natural loss of foot muscles in the bipedal jerboa, . Although adults have no muscles in their feet, newborn animals have muscles that rapidly disappear soon after birth.
View Article and Find Full Text PDFAims: Recommendations for the management of women with suspected uncomplicated lower urinary tract infections (UTIs) include presumptive antibiotics with or without obtaining a urine culture (UCx). However, with increasing antibiotic resistance, efforts to decrease antibiotic usage are vital. Therefore, the objective of this study was to determine if the presumptive treatment of women with suspected uncomplicated UTIs is contributing to unnecessary antibiotic usage.
View Article and Find Full Text PDFIntegr Comp Biol
November 2019
The variety of limb skeletal proportions enables a remarkable diversity of behaviors that include powered flight in bats and flipper-propelled swimming in whales using extremes of a range of homologous limb architectures. Even within human limbs, bone lengths span more than an order of magnitude from the short finger and toe bones to the long arm and leg bones. Yet all of this diversity arises from embryonic skeletal elements that are each a very similar size at formation.
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