Maintaining diversity in structured populations.

PNAS Nexus

Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA.

Published: August 2025


Category Ranking

98%

Total Visits

921

Avg Visit Duration

2 minutes

Citations

20

Article Abstract

We examine population structures for their ability to maintain diversity in neutral evolution. We use the general framework of evolutionary graph theory and consider birth-death (bd) and death-birth (db) updating. The population is of size . Initially all individuals represent different types. The basic question is: what is the time until one type takes over the population? This time is known as consensus time in computer science and as total coalescent time in evolutionary biology. For the complete graph, it is known that is quadratic in for db and bd. For the cycle, we prove that is cubic in for db and bd. For the star, we prove that is cubic for bd and quasilinear ( ) for db. For the double star, we show that is quartic for bd. We derive upper and lower bounds for all undirected graphs for bd and db. We also show the Pareto front of graphs (of size ) that maintain diversity the longest for bd and db. Further, we show that some graphs that quickly homogenize can maintain high levels of diversity longer than graphs that slowly homogenize. For directed graphs, we give simple contracting star-like structures that have superexponential time scales for maintaining diversity.

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC12363668PMC
http://dx.doi.org/10.1093/pnasnexus/pgaf252DOI Listing

Publication Analysis

Top Keywords

maintaining diversity
8
maintain diversity
8
prove cubic
8
time
5
graphs
5
diversity structured
4
structured populations
4
populations examine
4
examine population
4
population structures
4

Similar Publications

Background: The neonatal period is critical for oral microbiome establishment, but temporal patterns in preterm newborns remain unclear. This study examined longitudinal microbiome changes in full-term and preterm newborns and assessed perinatal and clinical influences.

Methods: Oral swabs were collected from 98 newborns (23 full-term, 75 preterm).

View Article and Find Full Text PDF

Hypocretin: a promising target for the regulation of homeostasis.

Front Neurosci

August 2025

Beijing Life Science Academy, Beijing, China.

Hypocretin, also known as orexin, is a hypothalamic neuropeptide that regulates essential physiological processes including arousal, energy metabolism, feeding behavior, and emotional states. Through widespread projections and two G-protein-coupled receptors-HCRT-1R and HCRT-2R-the hypocretin system exerts diverse modulatory effects across the central nervous system. The role of hypocretin in maintaining wakefulness is well established, particularly in narcolepsy type 1 (NT1), where loss of hypocretin neurons leads to excessive daytime sleepiness and cataplexy.

View Article and Find Full Text PDF

OpenML is an open-source platform that democratizes machine-learning evaluation by enabling anyone to share datasets in uniform standards, define precise machine-learning tasks, and automatically share detailed workflows and model evaluations. More than just a platform, OpenML fosters a collaborative ecosystem where scientists create new tools, launch initiatives, and establish standards to advance machine learning. Over the past decade, OpenML has inspired over 1,500 publications across diverse fields, from scientists releasing new datasets and benchmarking new models to educators teaching reproducible science.

View Article and Find Full Text PDF

Background: Paediatric patients who underwent surgery for mitral regurgitation (MR) have a high risk of recurrence or death; however, no prediction tool has been developed to risk-stratify this challenging subpopulation.

Methods: In this multicentre cohort study, paediatric patients undergoing surgery for congenital MR in Shanghai Children's Medical Center in January 1st, 2009-December 31st, 2022 were included for analysis while those had a combination with infective endocarditis, anomalous left coronary artery from the pulmonary artery, rheumatic valvular disease, connective tissue disease, or single ventricle were excluded. A Cox regression model predictive of the primary outcome (a composite of mortality or mitral valve [MV] re-operation) was derived and converted to a point-based risk score.

View Article and Find Full Text PDF

Background And Aim: Indonesia's indigenous Kacang goat population is in decline, posing a threat to food security and genetic diversity. maturation and cryopreservation techniques are key strategies for genetic conservation. However, heat shock stress during cryopreservation can compromise oocyte viability.

View Article and Find Full Text PDF