We explored a 13-year genetic survey of the major histocompatibility complex (MHC) and neutral loci of the Soay sheep population of St Kilda to test the existence and causes of balancing selection at the MHC. The sheep population experiences demographic fluctuations, partly driven by the nematode Teladorsagia circumcincta. The spatial differentiation detected at the MHC was comparable to that at neutral loci between 1988 and 1996, but significantly lower between 1996 and 2000. The rate of temporal genetic differentiation was higher at the MHC, but within the Eastern heft only. These comparisons of spatial and temporal divergence at MHC and non-MHC loci provide strong evidence of balancing selection at the MHC, acting through spatial and temporal heterogeneity in selection pressure. This heterogeneity could be due to fluctuations in the selection imposed by parasites, either directly, because the prevalence in T. circumcincta varies in space and time, or indirectly, because the fitness costs of infection may vary with resource availability.

Download full-text PDF

Source
http://dx.doi.org/10.1038/sj.hdy.6800735DOI Listing

Publication Analysis

Top Keywords

balancing selection
12
spatial temporal
12
genetic survey
8
fluctuations selection
8
neutral loci
8
sheep population
8
selection mhc
8
mhc
7
selection
6
long-term genetic
4

Similar Publications

Optical techniques, such as functional near-infrared spectroscopy (fNIRS), contain high potential for the development of non-invasive wearable systems for evaluating cerebral vascular condition in aging, due to their portability and ability to monitor real-time changes in cerebral hemodynamics. In this study, thirty-six healthy adults were measured by single channel fNIRS to explore differences between two age groups using machine learning (ML). The subjects, measured during functional magnetic resonance imaging (fMRI) at Oulu University Hospital, were divided into young (age ≤ 32) and elderly (age ≥ 57) groups.

View Article and Find Full Text PDF

Purpose: Pituitary adenomas, despite their histologically benign nature, can severely impact patients' quality of life due to hormone hypersecretion. Invasion of the medial wall of the cavernous sinus (MWCS) by these tumors complicates surgical outcomes, lowering biochemical remission rates and increasing recurrence. This study aims to share our institutional experience with the selective resection of the MWCS in endoscopic pituitary surgery.

View Article and Find Full Text PDF

Patient-centred care and technical challenges during polytrauma imaging - Experiences from radiography students.

Radiography (Lond)

January 2025

Department of Radiography, School of Allied Health Sciences, Faculty of Health Sciences and Veterinary Medicine, University of Namibia, P.O Box 13301, Windhoek, Namibia. Electronic address:

Introduction: Patient-centred care (PCC) is essential in radiography for polytrauma patients emphasising empathy, clear communication, and patient well-being. Polytrauma patients require tailored imaging approaches, often involving multiple modalities. Managing and handling these patients during imaging are key components of radiography training to develop the necessary competencies.

View Article and Find Full Text PDF

AGA Clinical Practice Guideline on the Prevention and Treatment of Hepatitis B Virus Reactivation in At-Risk Individuals.

Gastroenterology

February 2025

Section of Gastroenterology and Hepatology, Veterans Affairs Northeast Ohio Health Care System, Cleveland, Ohio; Division of Gastroenterology and Hepatology, Case Western Reserve University, Cleveland, Ohio.

Background & Aims: Hepatitis B reactivation (HBVr) can occur due to a variety of immune-modulating exposures, including multiple drug classes and disease states. Antiviral prophylaxis can be effective in mitigating the risk of HBVr. In select cases, clinical monitoring without antiviral prophylaxis is sufficient for managing the risk of HBVr.

View Article and Find Full Text PDF

Background: The benefit of mechanical circulatory support (MCS) with Impella (Abiomed, Inc, Danvers, MA) for patients undergoing non-emergent, high-risk percutaneous coronary intervention (HR-PCI) is unclear and currently the subject of a large randomized clinical trial (RCT), PROTECT IV. While contemporary registry data from PROTECT III demonstrated improvement of outcomes with Impella when compared with historical data (PROTECT II), there is lack of direct comparison to the HR-PCI cohort that did not receive Impella support.

Methods: We retrospectively identified patients from our institution meeting PROTECT III inclusion criteria (left ventricular ejection fraction [LVEF] <35% with unprotected left main or last remaining vessel or LVEF <30% undergoing multivessel PCI), and compared this group (NonIMP) to the published outcomes data from the PROTECT III registry (IMP).

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!