A recent study of a pair of sympatric species of cichlids in Lake Apoyo in Nicaragua is viewed as providing probably one of the most convincing examples of sympatric speciation to date. Here, we describe and study a stochastic, individual-based, explicit genetic model tailored for this cichlid system. Our results show that relatively rapid (<20,000 generations) colonization of a new ecological niche and (sympatric or parapatric) speciation via local adaptation and divergence in habitat and mating preferences are theoretically plausible if: (i) the number of loci underlying the traits controlling local adaptation, and habitat and mating preferences is small; (ii) the strength of selection for local adaptation is intermediate; (iii) the carrying capacity of the population is intermediate; and (iv) the effects of the loci influencing nonrandom mating are strong. We discuss patterns and timescales of ecological speciation identified by our model, and we highlight important parameters and features that need to be studied empirically to provide information that can be used to improve the biological realism and power of mathematical models of ecological speciation.
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http://dx.doi.org/10.1111/j.1365-294X.2007.03305.x | DOI Listing |
Ann Clin Transl Neurol
December 2024
Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
Objectives: To explore the efficacy of ofatumumab in new onset narcolepsy type 1 following SARS-CoV-2 infection.
Methods: We present a 9-year-old girl who experienced new onset narcolepsy type 1 following SARS-CoV-2 infection. Polysomnography (PSG) followed by a daytime multiple sleep latency test (MSLT) was under taken after admission.
JBJS Case Connect
October 2024
Department of Pediatric Orthopaedic Surgery, Hospital for Special Surgery, New York, New York.
Case: A pediatric patient with focal fibrocartilaginous dysplasia (FFCD) developed angular deformity and growth arrest despite standard guided growth management. The patient underwent implant-mediated guided growth for proximal tibia varus deformity which recurred; subsequently, a physeal bar of the medial proximal tibia was diagnosed, which progressed to physeal arrest.
Conclusion: Treatment options for FFCD-associated angular deformity include observation and guided growth.
Neurology
January 2025
Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India; and.
A 16-year-old adolescent girl presented with progressive walking imbalance, uncoordination of her limbs, impaired proprioceptive sensation distal to her wrists and ankles, and sensorineural hearing loss. Her evaluation revealed diffuse cerebellar atrophy, a demyelinating neuropathy, and hypergonadotropic hypogonadism. In this article, we present a systematic approach to a patient with early-onset ataxia, cerebellar atrophy, and demyelinating neuropathy.
View Article and Find Full Text PDFNeurology
January 2025
From the Neurology Department, Unidade Local de Saúde de Coimbra, Portugal.
A 35-year-old woman presented with a progressive 3-year history of personality changes and gait impairment. Neurologic examination revealed bilateral optic atrophy, spastic paraparesis, and impaired vibratory sensation in all limbs, and neuropsychological evaluation identified a frontotemporal cognitive impairment. In this article, we review the differential diagnosis for a young woman with chronic frontotemporal dysfunction, optic atrophy, and dorsolateral myelopathy in a stepwise multidisciplinary approach.
View Article and Find Full Text PDFNeurology
January 2025
Faculty of Medicine, University of Geneva, Switzerland.
Early detection of focal cortical dysplasia (FCD) using brain MRI in young children presenting with drug-resistant epilepsy may facilitate prompt surgical treatment, resulting in better control of seizures and decreased associated cognitive difficulties. Characteristics of FCD described in the literature are predominantly based on MRI findings in a fully myelinated brain; therefore, changes occurring during early brain maturation are not well known. In this case report, we describe distinct MRI features of a FCD visualized best before completion of myelination of the cortex and subcortical white matter.
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