The increasing abundance of human genetic data has shown that the geographical patterns of worldwide genetic diversity are best explained by human expansion out of Africa. This expansion is modelled well by prolonged migration from a single origin in Africa with multiple subsequent serial founding events. We discuss a new simulation model for the serial founder effect out of Africa and compare it with results from previous studies. Unlike previous models, we distinguish colonization events from the continued exchange of people between occupied territories as a result of mating. We conduct a search through parameter space to estimate the range of parameter values that best explain key statistics from published data on worldwide variation in microsatellites. The range of parameters we use is chosen to be compatible with an out-of-Africa migration at 50-60Kyr ago and archaeo-ethno-demographic information. In addition to a colonization rate of 0.09-0.18, for an acceptable fit to the published microsatellite data, incorporation into existing models of exchange between neighbouring populations is essential, but at a very low rate. A linear decay of genetic diversity with geographical distance from the origin of expansion could apply to any species, especially if it moved recently into new geographical niches.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2674957 | PMC |
http://dx.doi.org/10.1098/rspb.2008.0750 | DOI Listing |
Acad Radiol
January 2025
Medical Image Processing Group, 602 Goddard building, 3710 Hamilton Walk, Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104 (M.L., M.A., J.K.U., Y.T., C.W., N.P., S.M., D.A.T.). Electronic address:
Rationale And Objectives: Cardiovascular toxicity is a well-known complication of thoracic radiation therapy (RT), leading to increased morbidity and mortality, but existing techniques to predict cardiovascular toxicity have limitations. Predictive biomarkers of cardiovascular toxicity may help to maximize patient outcomes.
Methods: The machine learning optimal biomarker (OBM) method was employed to predict development of cardiotoxicity (based on serial echocardiographic measurements of left ventricular ejection fraction and longitudinal strain) from computed tomography (CT) images in patients with thoracic malignancy undergoing RT.
A A Pract
January 2025
From the Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Palo Alto, California.
In this case, the electroencephalogram (EEG) was used to guide anesthesia care for a pediatric patient with Alexander's Disease undergoing serial intrathecal injections. Previous procedures using a standard maintenance propofol dose of up to 225 µg/kg/min led to postanesthetic recovery times of over 6 hours, requiring a neurology consult for noncoherence. The EEG assisted in guiding maintenance propofol dosing to 75 µg/kg/min, decreasing postanesthetic wash-off and postanesthesia care unit (PACU) recovery time by 50%.
View Article and Find Full Text PDFActa Neuropathol Commun
January 2025
Department of Neurosurgery, University of California, Los Angeles, CA, USA.
The incidence of brain metastases (BrM) in patients with metastatic melanoma is reported to be 30-50% and constitutes the third most frequent BrM after breast and renal cancers. Treatment strategies including surgical resection, stereotactic radiation, and immunotherapy have improved clinical response rates and overall survival, but the changes that occur in circulating melanoma cells to promote invasion of the brain are not fully understood. To investigate brain tropism, we generated new variants of the B16 mouse melanoma model by serially passaging B16 cells through the brain of immune competent syngeneic C57BL/6 mice.
View Article and Find Full Text PDFAlzheimers Res Ther
January 2025
Alzheimer Center Amsterdam, Department of Neurology, Vrije Universiteit Amsterdam, Amsterdam UMC, Amsterdam, The Netherlands.
Background: Disease-modifying therapies targeting the diverse pathophysiology of Alzheimer's disease (AD), including neuroinflammation, represent potentially important and novel approaches. The glucagon-like peptide-1 receptor agonist semaglutide is approved for the treatment of type 2 diabetes and obesity and has an established safety profile. Semaglutide may have a disease-modifying, neuroprotective effect in AD through multimodal mechanisms including neuroinflammatory, vascular, and other AD-related processes.
View Article and Find Full Text PDFSpinal Cord
January 2025
McKnight Brain Institute, University of Florida, Gainesville, FL, USA.
Study Design: Experimental Animal Study.
Objective: To continue validating an antibody which targets an epitope of neurofilament light chain (NF-L) only available during neurodegeneration and to utilize the antibody to describe the pattern of axonal degeneration 10 days post-unilateral C4 contusion in the rat.
Setting: University of Florida laboratory in Gainesville, USA.
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!